Electronic Oxide-Support Strong Interactions in the Graphdiyne-Supported Cuprous Oxide Nanocluster Catalyst

Auxiliary Ligand-Coordinated Nanoconfined Hydrophobic Microenvironments in Nickel(II)-Acetylide Framework for Enhanced CO2 Photoreduction

Metal-acetylide frameworks (MAFs), featuring metal-bis(acetylide) linkages (─C≡C─M─C≡C─), are emerging as a new class of 2D nanomaterials with promise in catalysis. Here, we report a new 2D NiII-acetylide framework, TPA-Ni(PR3)2-GYs, that incorporates the NiII(PR3)2 moiety [R = CH3 (Me), CH2CH3 (Et), and CH2CH2CH2CH3 (Bu)] into tris(4-ethynylphenyl)amine-based graphdiyne framework (TPA-GDY). As a result, TPA-Ni(PBu3)2-GY exhibits an exceptional photocatalytic CO2 reduction activity of 3807 µmol g-1 h-1 and a high selectivity of 99.4% for CO production upon visible light irradiation. Mechanistic investigations reveal a strong orbital matching effect between the d orbitals of NiII and the p orbitals of the alkynyl C atoms in organic ligands, which not only accelerates the transfer and separation of photogenerated charge carriers but also reduces the reaction potential barrier for the formation of *COOH intermediates. Furthermore, the high hydrophobicity of the auxiliary coordinated ligands (trialkylphosphines) to Ni center, particularly tributylphosphine, creates a nanoconfined space that enhances both the accessibility of CO2 and the utilization of NiII catalytic active sites while inhibiting hydrogen evolution. This study highlights the benefit of modulating the microenvironment around the coordinated metal center to enhance the performance of catalysts with direct metal-acetylide bonding.

Multidimensional Co-Design and Performance-Mechanism Study of Novel Graphdiyne Composites with Microwave Absorbing Structures

Graphdiyne (GDY), an emerging member in the carbon material family, possesses abundant chemical bonds, extended conjugated systems, and superior charge carrier mobility, establishing it as a promising novel microwave absorption material. Capitalizing on these attributes, in this work, a flower-like GDY@Cu2O composite with a unique nanowall structure is prepared by a one-step microemulsion method. Remarkably, temperature-mediated enhancement of electron transport coupled with induced multipolarization synergistically boosts the microwave absorption performance. The optimal specimen (GDY@Cu2O-700) achieves an effective absorption bandwidth (EAB) of 6.1 GHz at 2.2 mm matched thickness, with a minimum reflection loss of -49.9 dB@17.7 GHz. Furthermore, a metamaterial is designed at the millimeter scale using GDY@Cu2O-700 as the microwave absorbing functional component. Following optimization via 3D electromagnetic simulation software, this metamaterial demonstrates an ultra-broad EAB spanning 34.1 GHz in the range of 2-40 GHz. This pioneering study delineates the electromagnetic wave absorption characteristics of GDY-based microspheres with GDY as the primary constituent and provides a valuable reference for designing innovative wave-absorbing materials.

Interfacial Atom Rearrangement Drives Potential-Adaptive Electrocatalytic Olefin Hydrogenation

Dynamic rearrangement of metal atoms at heterointerfaces by chemical bond conversion drives high efficiency electrocatalytic processes, which is a new concept in the field of electrocatalysis and a new discovery to directly improve catalytic activity. It is of great significance to explore transformative catalytic systems that directly control the interfacial structure and function of atomic composition. As an emerging 2D carbon allotrope featuring unique sp-sp2 co-hybridization, graphdiyne (GDY) offers unprecedented advantages for heterointerface engineering. In particular, the uneven surface charge distribution of GDY, high distribution of active sites and customizable electronic structures provide unprecedented opportunities for the development of a new generation of catalytic systems. Here, we report a new idea to directly control the cooperative growth and drive metal atomic rearrangement on the interface of GDY/NiPd/GDY. The results of atomic-resolution electron microscopy characterization revealed two unique interfacial phenomena: i) GDY-induced massive dislocation formation within NiPd nanoalloys and ii) rearrangement of surface metal atoms from (111) to (200) facets. Detailed spectroscopic analysis further demonstrated the composition-dependent evolution of elemental valence states and stoichiometric ratios. This atomic-level restructuring establishes a charge-redistribution network featuring non-integer charge transfer, which improves the overall conductivity and intrinsic activity. What is even more encouraging is that this electrocatalytic olefin hydrogenation is carried out in an aqueous solution. The GDY/NiPd/GDY heterostructure achieves exceptional activity (turnover frequency: 6.8 s-1), stability (>5 cycles), and chemo-selectivity (-100%), which is superior to traditional catalysts.

Electroreduction of acetonitrile to ethylamine by thin carbon-coated copper catalysts with rich active interphases

Thin carbon-coated copper catalysts facilitate the electroreduction of acetonitrile to ethylamine, in which a faradaic selectivity of 98% and a partial current density of 117 mA cm-2 towards ethylamine at -0.8 VRHE can be achieved. The carbon shells benefit the formation of rich active interfaces and suppress copper agglomeration.

Inverse Oxide/Alloy-Structured Nanozymes with NIR-Triggered Enzymatic Cascade Regulation of ROS Homeostasis for Efficient Wound Healing

The precise spatiotemporal control of reactive oxygen species (ROS) generation and scavenging remains pivotal for infected wound healing. However, conventional nanozymes fail to adaptively regulate ROS dynamics across inflammatory and proliferative phases. A near-infrared (NIR)-activated inverse oxide/alloy-structured nanozyme (Co7Fe3/ZnO@C) is developed, featuring enzymatic cascade activities to tune ROS homeostasis through synergistic chemodynamic (CDT), photodynamic (PDT), and photothermal (PTT) therapies. The nanozyme orchestrates a self-regulated cascade: peroxidase (POD)-like activity initially generates bactericidal hydroxyl radicals in acidic wounds, while subsequent NIR triggers hot electron transfer from Co7Fe3 to ZnO, facilitating synchronized superoxide dismutase (SOD)-like, catalase (CAT)-like and hydroxyl radical antioxidant capacity (HORAC) activities to scavenge residual ROS. This cascaded network dynamically balances ROS production (POD) and scavenging (NIR-driven SOD/CAT/HORAC), eradicating bacteria while resolving inflammation. In vitro/vivo studies have shown that the proposed method for maintaining ROS homeostasis can markedly enhance the rate of wound healing by the regulation of the inflammatory environment within the injured tissue and the facilitation of rapid re-epithelialization. This work provides an intelligent nanozyme platform that simulates the function of natural enzymes and constructs a cascade reaction strategy to balance the antibacterial and anti-inflammatory demands in the wound microenvironment.

The electroreduction-free stripping analysis of copper (II) ions and the voltammetric detection of nonylphenol and tetracycline based on graphdiyne/carbon nanotubes

The heavy metal ions (HMI) and π-electronical pollutants are two main types of environmental water contaminants, thus designing a universal sensor for their detection is considerable important. Meanwhile, graphdiyne (GDY) as a star material exhibits many unique advantages, especially superior adsorption and self-reducing property to HMI as well as great affinity to π-electron targets. Herein, by low-cost utilizing carbon nanotubes (CNTs) as the template dedicated to improve the conductivity and dispersibility of GDY, a multifunctional nanohybrid GDY/CNTs was prepared and then revealed successfully as a universal electrochemical sensing material for the HMI and π-electronical pollutants by adopting three models: (a) based on the in-situ adsorption and self-reduction capabilities of GDY towards HMI, an innovative electroreduction-free stripping voltammetry (FSV) sensing strategy was proposed for HMI detection via adopting Cu2+ as a representative, which can effectively avoid the electroreduction process compared with the common anodic stripping voltammetry method; (b) by selecting nonylphenol (NP) and tetracycline (TC) as two representative targets, the sensing performances of GDY/CNTs for the π-electronical pollutants were also confirmed. After optimizing the related experimental parameters, the as-prepared GDY/CNTs exhibits superior analytical performances (the obtained detection limits for Cu2+, NP and TC are respectively 1.6 nM, 6.67 nM and 1.67 nM coupled with the linearities of 0.005-10.0 μM, 0.02-25.0 μM and 0.005-6.0 μM) owing to the synergistic advantages of GDY and CNTs. This work revealed the as-prepared GDY/CNTs nanohybrids can be utilized as a robust universal sensing material for HMI and pollutants consisting of π-electrons, and especially the proposed FSV sensing strategy is very promising, exhibiting great potential applications.

Tailoring asymmetric RuCu dual-atom electrocatalyst toward ammonia synthesis from nitrate

Atomically dispersed Ru-Cu dual-atom catalysts (DACs) with asymmetric coordination are critical for sustainable ammonia production via electrochemical nitrate reduction (NO3RR), but their rational synthesis remains challenging. Here, we report a pulsed discharge strategy that injects a microsecond pulse current into ruthenium (Ru) and copper (Cu) precursors supported by nitrogen-doped graphene aerogels (NGA). The atomically dispersed Ru and Cu dual atoms anchor onto nanopore defects of NGA (RuCu DAs/NGA) through explosive decomposition of the metal salt nanocrystals. The catalyst achieves 95.7% Faraday efficiency and 3.1 mg h-1 cm-2 NH3 yield at -0.4 V vs. RHE. In situ studies reveal an asymmetric RuN2-CuN3 active-site dynamic evolution during NO3RR. Density functional theory calculations demonstrate that asymmetric RuN2CuN3/C structure synergistically optimizes intermediate adsorption and reduces energy barriers of key steps. The pulsed discharge enables ultrafast synthesis of various DACs (e.g., PtCu, AgCu, PdCu, FeCu, CoCu, NiCu) with tailored coordination environments, offering a general-purpose strategy for the precise preparation of atomically dispersed dual-atom catalysts, which are traditionally challenging to synthesize.

Graphdiyne and its heteroatom-doped derivatives for Li-ion/metal batteries

Graphdiyne (GDY), which is composed of benzene rings and acetylene linkage units, is a new allotrope of carbon material. In particular, the large triangular pores of GDY, with a diameter of 5.4 Å, theoretically predict a higher lithium embedding density than traditional graphite anodes, making it a promising candidate for energy storage materials in lithium-ion (Li-ion) batteries. GDY is primarily synthesized via a cross-coupling reaction of hexaethynylbenzene (HEB). Under similar preparation conditions, the cross-coupling reaction of aryne precursors, other than HEB, yields many GDY heteroatom-doped derivatives. This introduces numerous heteroatomic defects as well as electrochemically active sites, potentially enhancing electrochemical performance. Recent advancements have focused on utilizing GDY and its heteroatom-doped derivatives as electrode materials or composite materials in Li-ion/metal batteries. This review systematically summarizes the strategies developed for GDY and its heteroatom-doped derivatives. Notably, recent research on the effects of morphology and chemical/electronic structure on performance, particularly new conceptual mechanisms in Li-ion/metal batteries, including self-expanding Li-ion transport channels and a capture/pore filling-intercalation hybrid mechanism, is briefly described. The results presented herein highlight the significant potential of GDY and its heteroatom-doped derivatives for energy storage applications and inspire further development.

A Highly Conjugated Nickel(II)-Acetylide Framework for Efficient Photocatalytic Carbon Dioxide Reduction

The incorporation of transition-metal single atoms as molecular functional entities into the skeleton of graphdiyne (GDY) to construct novel two-dimensional (2D) metal-acetylide frameworks, known as metalated graphynes (MGYs), is a promising strategy for developing efficient catalysts, which can combine the tunable charge transfer of GDY frameworks, the catalytic activity of metal and the precise distribution of single metallic centers. Herein, four highly conjugated MGY photocatalysts based on NiII, PdII, PtII, and HgII were synthesized for the first time using the 'bottom-up' strategy through the use of M-C bonds (-C≡C-M-C≡C-). Remarkably, the NiII-based graphyne (TEPY-Ni-GY) exhibited the highest CO generation rate of 18.3 mmol g-1 h-1 and a selectivity of 98.8 %. This superior performance is attributed to the synergistic effects of pyrenyl and -C≡C-Ni(PBu3)2-C≡C- moieties. The pyrenyl block functions as an intramolecular π-conjugation channel, facilitating kinetically favorable electron transfer, while the -C≡C-Ni(PBu3)2-C≡C- moiety serves as the catalytic site that enhances CO2 adsorption and activation, thereby suppressing competitive hydrogen evolution. This study provides a new perspective on MGY-based photocatalysts for developing highly active and low-cost catalysts for CO2 reduction.

sp Carbon Disrupting Axial Symmetry of Local Electric Field for Biomimetic Construction of Three-Dimensional Geometric and Electronic Structure in Nanozyme for Sensing and Microplastic Degradation

The catalytic efficiency of natural enzymes depends on the precise electronic interactions between active centers and cofactors within a three-dimensional (3D) structure. Single-atom nanozymes (SAzymes) attempt to mimic this structure by modifying metal active sites with molecular ligands. However, SAzymes struggle to match the catalytic efficiency of natural enzymes due to constraints in active site proximity, quantity, and the inability to simulate electron transfer processes driven by internal electronic structures of natural enzymes. This study introduces a universal spatial engineering strategy in which molecular ligands are replaced with graphdiyne (GDY) to induce d-π orbital hybridization with copper nanoparticles (Cu NPs), leading to an asymmetric electron-rich distribution along the longitudinal axis that mimics the local electric field of natural laccase. Moreover, multiple sp bonds within GDY scaffold effectively anchor Cu NPs, facilitating the construction of 3D geometric structure similar to that of natural laccase. An enzymatic activity of 82.53 U mg-1 is achieved, 4.72 times higher than that of natural laccase. By reconstructing both 3D structures and local electric fields of natural enzymes through d-π orbital hybridization, this approach enhances electron interactions between cofactors, active centers, and substrates, and offers a versatile framework for biomimetic design of nanozymes.

Transient pulsed discharge preparation of graphene aerogel supports asymmetric Cu cluster catalysts promote CO2 electroreduction

Designing asymmetrical structures is an effective strategy to optimize metallic catalysts for electrochemical carbon dioxide reduction reactions. Herein, we demonstrate a transient pulsed discharge method for instantaneously constructing graphene-aerogel supports asymmetric copper nanocluster catalysts. This process induces the convergence of copper atoms decomposed by copper chloride onto graphene originating from the intense current pulse and high temperature. The catalysts exhibit asymmetrical atomic and electronic structures due to lattice distortion and oxygen doping of copper clusters. In carbon dioxide reduction reaction, the selectivity and activity for ethanol production are enhanced by the asymmetric structure and abundance of active sites on catalysts, achieving a Faradaic efficiency of 75.3% for ethanol and 90.5% for multicarbon products at -1.1 V vs. reversible hydrogen electrode. Moreover, the strong interactions between copper nanoclusters and graphene-aerogel support confer notable long-term stability. We elucidate the key reaction intermediates and mechanisms on Cu4O-Cu/C2O1 moieties through in situ testing and density functional theory calculations. This study provides an innovative approach to balancing activity and stability in asymmetric-structure catalysts for energy conversion.

In-situ activation of biomimetic single-site bioorthogonal nanozyme for tumor-specific combination therapy

Copper-catalyzed click chemistry offers creative strategies for activation of therapeutics without disrupting biological processes. Despite tremendous efforts, current copper catalysts face fundamental challenges in achieving high efficiency, atom economy, and tissue-specific selectivity. Herein, we develop a facile "mix-and-match synthetic strategy" to fabricate a biomimetic single-site copper-bipyridine-based cerium metal-organic framework (Cu/Ce-MOF@M) for efficient and tumor cell-specific bioorthogonal catalysis. This elegant methodology achieves isolated single-Cu-site within the MOF architecture, resulting in exceptionally high catalytic performance. Cu/Ce-MOF@M favors a 32.1-fold higher catalytic activity than the widely used MOF-supported copper nanoparticles at single-particle level, as first evidenced by single-molecule fluorescence microscopy. Furthermore, with cancer cell-membrane camouflage, Cu/Ce-MOF@M demonstrates preferential tropism for its parent cells. Simultaneously, the single-site CuII species within Cu/Ce-MOF@M are reduced by upregulated glutathione in cancerous cells to CuI for catalyzing the click reaction, enabling homotypic cancer cell-activated in situ drug synthesis. Additionally, Cu/Ce-MOF@M exhibits oxidase and peroxidase mimicking activities, further enhancing catalytic cancer therapy. This study guides the reasonable design of highly active heterogeneous transition-metal catalysts for targeted bioorthogonal reactions.

Applications of metal nanoclusters supported on the two-dimensional material graphene in electrocatalytic carbon dioxide reduction

Metal nanoclusters (MNCs) have been demonstrated to exhibit superior catalytic performance compared to single nanoparticles. This is attributed to their quantized electronic structure, unique geometrical stacking and abundant active sites. While the exposed metal atoms can markedly enhance the efficiency of catalysis, unfortunately, MNCs are susceptible to agglomeration, which impairs their catalytic activity and stability. Graphene is a two-dimensional material consisting of a single atomic layer formed by the hybridization of the s and p orbitals of carbon atoms. It exhibits stable physical and chemical properties and has an easily controllable structure, making it an ideal carrier for MNCs. When metal nanoclusters (MNCs) are loaded on a graphene substrate, the MNCs can form a stable binding site on the graphene substrate. Furthermore, the construction of a defective structure on the graphene substrate enables the formation of robust interactions between the metal atoms of the MNCs and the substrate, facilitating the rapid establishment of electron conduction pathways and markedly enhancing the electrocatalytic performance. This paper presents a review of the applications of metal nanoclusters supported on graphene skeletons in the field of the electrocatalytic CO2 reduction reaction (CO2RR). Firstly, we briefly introduce the reaction mechanism of the CO2RR, then we systematically discuss the synthesis strategies, properties and applications of metal nanoclusters in electrocatalytic carbon dioxide reduction from both experimental and theoretical perspectives, and lastly, we discuss the opportunities and challenges of metal nanocluster catalysts supported on carbon materials.

0D/2D heterojunction constructed by Ag2S quantum dots anchored on graphdiyne (g-CnH2n-2) nanosheets for wide spectrum photocatalytic H2 evolution

Precisely crafting heterojunctions for efficient charge separation is a major obstacle in the realm of photocatalytic hydrogen evolution. A 0D/2D heterojunction was successfully fabricated by anchoring Ag2S quantum dots (Ag2S QDs) onto graphdiyne (GDY) nanosheets (Ag2S QDs/GDY) using a straightforward physical mixing technique. This unique structure allows for excellent contact between GDY and Ag2S QDs, thereby enhancing the rate of charge transfer. The light absorption capabilities of Ag2S QDs/GDY extend up to 1200 nm, enabling strong absorption of light, including infrared. Through DFT calculations and in-situ XPS analysis, it was demonstrated that incorporating Ag2S QDs onto GDY effectively modulates the electronic structure, promotes an internal electric field, and facilitates directional electron transfer. This directed electron transfer enhances the utilization of electrons by GDY and Ag2S QDs, with the added benefit of Ag2S QDs serving as electron reservoirs for efficient photocatalytic hydrogen evolution. A 7 %Ag2S QDs/GDY composite exhibited impressive efficiency and stable performance in photocatalytic hydrogen evolution (2418 μmol g-1 h-1), which is much higher than that of GDY and Ag2S QDs. This study conclusively demonstrates that the 0D/2D heterojunction formed by GDY and Ag2S QDs can establish high-quality contact and efficient charge transfer, ultimately enhancing photocatalytic performance.

Electron Delocalization Disentangles Activity-Selectivity Trade-Off of Transition Metal Phosphide Catalysts in Oxidative Desulfurization

Breaking the activity-selectivity trade-off has been a long-standing challenge in catalysis. Here, we proposed a nanoheterostructure engineering strategy to overcome the trade-off in metal phosphide catalysts for the oxidative desulfurization (ODS) of fuels. Experimental and theoretical results demonstrated that electron delocalization was the key driver to simultaneously achieve high activity and high selectivity for the molybdenum phosphide (MoP)/tungsten phosphide (WP) nanoheterostructure catalyst. The electron delocalization not only promoted the catalytic pathway transition from predominant radicals to singlet oxygens in H2O2 activation but also simultaneously optimized the adsorption of reactants and intermediates on Mo and W sites. The presence of such dual-enhanced active sites ideally compensated for the loss of activity due to the nonradical catalytic pathway, consequently disentangling the activity-selectivity trade-off. The resulting catalyst (MoWP2/C) unprecedentedly achieved 100% removal of thiophenic compounds from real diesel at an initial concentration of 2676 ppm of sulfur with a high turnover frequency (TOF) of 105.4 h-1 and a minimal O/S ratio of 4. This work provides fundamental insight into the structure-activity-selectivity relationships of heterogeneous catalysts and may inspire the development of high-performance catalysts for ODS and other catalytic fields.

Optimization of Carbon-Defect Engineering to Boost Catalytic Ozonation Efficiency of Single Fe─N4 Coordination Motif

Carbon-defect engineering in single-atom metal-nitrogen-carbon (M─N─C) catalysts by straightforward and robust strategy, enhancing their catalytic activity for volatile organic compounds, and uncovering the carbon vacancy-catalytic activity relationship are meaningful but challenging. In this study, an iron-nitrogen-carbon (Fe─N─C) catalyst is intentionally designed through a carbon-thermal-diffusion strategy, exposing extensively the carbon-defective Fe─N4 sites within a micro-mesoporous carbon matrix. The optimization of Fe─N4 sites results in exceptional catalytic ozonation efficiency, surpassing that of intact Fe─N4 sites and commercial MnO2 by 10 and 312 times, respectively. Theoretical calculations and experimental data demonstrated that carbon-defect engineering induces selective cleavage of C─N bond neighboring the Fe─N4 motif. This induces an increase in non-uniform charges and Fermi density, leading to elevated energy levels at the center of Fe d-band. Compared to the intact atomic configuration, carbon-defective Fe─N4 site is more activated to strengthen the interaction with O3 and weaken the O─O bond, thereby reducing the barriers for highly active surface atomic oxygen (*O/*OO), ultimately achieving efficient oxidation of CH3SH and its intermediates. This research not only offers a viable approach to enhance the catalytic ozonation activity of M─N─C but also advances the fundamental comprehension of how periphery carbon environment influences the characteristics and efficacy of M─N4 sites.

Interfacial Electronic Interaction in Amorphous-Crystalline CeOx-Sn Heterostructures for Optimizing CO2 to Formate Conversion

Formate, a crucial chemical raw material, holds significant promise for industrial applications in the context of CO2 electroreduction reaction (CO2RR). Despite its potential, challenges, such as poor selectivity and low formation rate at high current densities persist, primarily due to the competing hydrogen evolution reaction (HER) and high energy barriers associated with *OCHO intermediate generation. Herein, one-step chemical co-reduction strategy is employed to construct an amorphous-crystalline CeOx-Sn heterostructure, demonstrating remarkable catalytic performance in converting CO2 to formate. The optimized CeOx-Sn heterostructures reach a current density of 265.1 mA cm-2 and a formate Faraday efficiency of 95% at -1.07 V versus RHE. Especially, CeOx-Sn achieves a formate current density of 444.4 mA cm-2 and a formate production rate of 9211.8 µmol h-1 cm-2 at -1.67 V versus RHE, surpassing most previously reported materials. Experimental results, coupled with （density functional theory）DFT calculations confirm that robust interface interaction between CeOx and Sn active center induces electron transfer from crystalline Sn site to amorphous CeOx, some Ce4+of CeOx get electrons and convert to unsaturated Ce3+, optimizing the electronic structure of active Sn. This amorphous-crystalline heterostructure promotes electron transfer during CO2RR, reducing the energy barrier formed by *OCHO intermediates, and thus achieving efficient reduction of CO2 to formate.

Red Carbon Mediated Formation of Cu2O Clusters Dispersed on the Oxocarbon Framework by Fehling's Route and their Use for the Nitrate Electroreduction in Acidic Conditions

The oligomers of carbon suboxide, known as red carbon, exhibit a highly conjugated structure and semiconducting properties. Upon mild heat treatment, it transforms into a carbonaceous framework rich in oxygen surface terminations, called oxocarbon. In this study, the abundant oxygen functionalities are harnessed as anchors to create oxocarbon-supported nanohybrid electrocatalysts. Starting with single atomic Cu (II) strongly coordinated to oxygen atoms on red carbon, the Fehling reaction leads to the formation of Cu2O clusters. Simultaneously, a covalent oxocarbon framework emerges via cross-linking, providing robust support for Cu2O clusters. Notably, the oxocarbon support effectively stabilizes Cu2O clusters of very small size, ensuring their high durability in acidic conditions and the presence of ammonia. The synthesized material exhibits a superior electrocatalytic activity for nitrate reduction under acidic electrolyte conditions, with a high yield rate of ammonium (NH4 +) at 3.31 mmol h-1 mgcat -1 and a Faradaic efficiency of 92.5% at a potential of -0.4 V (vs RHE).

Copper Dispersed Covalent Organic Framework for Azide-Alkyne Cycloaddition and Fast Synthesis of Rufinamide in Water

A crystalline porous bipyridine-based Bpy-COF with a high BET surface area (1864 m2 g-1) and uniform mesopore (4.0 nm) is successfully synthesized from 1,3,5-tris-(4'-formyl-biphenyl-4-yl)triazine and 5,5'-diamino-2,2'-bipyridine via a solvothermal method. After Cu(I)-loading, the resultant Cu(I)-Bpy-COF remained the ordered porous structure with evenly distributed Cu(I) ions at a single-atom level. Using Cu(I)-Bpy-COF as a heterogeneous catalyst, high conversions for cycloaddition reactions are achieved within a short time (40 min) at 25 °C in water medium. Moreover, Cu(I)-Bpy-COF proves to be applicable for aromatic and aliphatic azides and alkynes bearing various substituents such as ester, hydroxyl, amido, pyridyl, thienyl, bulky triphenylamine, fluorine, and trifluoromethyl groups. The high conversions remain almost constant after five cycles. Additionally, the antiepileptic drug (rufinamide) is successfully prepared by a simple one-step reaction using Cu(I)-Bpy-COF, proving its practical feasibility for pharmaceutical synthesis.

Biphase Pd Nanosheets with Atomic-Hybrid RhOx/Pd Amorphous Skins Disentangle the Activity-Stability Trade-Off in Oxygen Reduction Reaction

The activity-stability trade-off relationship of oxygen reduction reaction (ORR) is a tricky issue that strikes the electrocatalyst population and hinders the widespread application of fuel cells. Here neoteric biphase Pd nanosheets that are structured with ultrathin two-dimensional crystalline Pd inner cores and ≈1 nm thin atomic-hybrid RhOx/Pd amorphous skins, named c/a-Pd@PdRh NSs, for disentangling this trade-off dilemma for alkaline ORR are developed. The superthin amorphous skins significantly amplify the quantity of flexibly low-coordinated atoms for electrocatalysis. An in situ selected oxidation of the top-surface Rh dopants creates atomically hybrid RhOx/Pd disorder surfaces. Detailed energy spectra and theoretical simulation confirm that these RhOx/Pd interfaces can arouse a surface charge redistribution, causing significant electron deficiency and lowered d-band center for surface Pd. Meanwhile, anticorrosive Rh/RhOx species can thermodynamically passivate the neighboring Pd atoms from oxidative dissolution. Thanks to these amplified interfacial effects, the biphase c/a-Pd@PdRh NSs simultaneously exhibit a superhigh ORR activity (5.92 A mg-1, 22.8 times that of Pt/C) and an outstanding long-lasting stability after 100k cycles of accelerated durability test, showcasing unprecedented electrocatalysts for breaking the activity-stability trade-off relationship of ORR. This work paves a bran-new strategy for designing high-performance electrocatalysts through creating modulated amorphous skins on low-dimensional nanomaterials.

Interfacial Bonding Induced Charge Transfer in Two-Dimensional Amorphous MoO3-x/Graphdiyne Oxide Non-Van der Waals Heterostructures for Dominant SERS Enhancement

Two-dimensional semiconductor-based nanomaterials have shown to be an effective substrate for Surface-enhanced Raman Scattering (SERS) spectroscopy. However, the enhancement factor (EF) tends to be relatively weak compared to that of noble metals and does not allow for trace detection of molecules. In this work, we report the successful preparation of two-dimensional (2D) amorphous non-van der Waals heterostructures MoO3-x/GDYO nanomaterials using supercritical CO2. Due to the synergistic effect of the localized surface plasmon resonance (LSPR) effect and the charge transfer effect, it exhibits excellent SERS performance in the detection of methylene blue (MB) molecules, with a detection limit as low as 10-14 M while the enhancement factor (EF) can reach an impressive 2.55×1011. More importantly, the chemical bond bridging at the MoO3-x/GDYO heterostructures interface can accelerate the electron transfer between the interfaces, and the large number of defective surface structures on the heterostructures surface facilitates the chemisorption of MB molecules. And the charge recombination lifetime can be proved by a ~1.7-fold increase during their interfacial electron-transfer process for MoO3-x/GDYO@MB mixture, achieving highly sensitive SERS detection.

Theoretical Prediction Leads to Synthesize GDY Supported InOx Quantum Dots for CO2 Reduction

The preparation of formic acid by direct reduction of carbon dioxide is an important basis for the future chemical industry and is of great significance. Due to the serious shortage of highly active and selective electrocatalysts leading to the development of direct reduction of carbon dioxide is limited. Herein the target catalysts with high CO2RR activity and selectivity were identified by integrating DFT calculations and high-throughput screening and by using graphdiyne (GDY) supported metal oxides quantum dots (QDs) as the ideal model. It is theoretically predicted that GDY supported indium oxide QDs (i.e., InOx/GDY) is a new heterostructure electrocatalyst candidate with optimal CO2RR performance. The interfacial electronic strong interactions effectively regulate the surface charge distribution of QDs and affect the adsorption/desorption behavior of HCOO* intermediate during CO2RR to achieve highly efficient CO2 conversion. Based on the predicted composition and structure, we synthesized the advanced catalytic system, and demonstrates superior CO2-to-HCOOH conversion performance. The study presents an effective strategy for rational design of highly efficient heterostructure electrocatalysts to promote green chemical production.

Efficient CO2 Electroreduction to Multicarbon Products at CuSiO3/CuO Derived Interfaces in Ordered Pores

Electrochemical CO2 conversion to value-added multicarbon (C2+) chemicals holds promise for reducing CO2 emissions and advancing carbon neutrality. However, achieving both high conversion rate and selectivity remains challenging due to the limited active sites on catalysts for carbon-carbon (C─C) coupling. Herein, porous CuO is coated with amorphous CuSiO3 (p-CuSiO3/CuO) to maximize the active interface sites, enabling efficient CO2 reduction to C2+ products. Significantly, the p-CuSiO3/CuO catalyst exhibits impressive C2+ Faradaic efficiency (FE) of 77.8% in an H-cell at -1.2 V versus reversible hydrogen electrode in 0.1 M KHCO3 and remarkable C2H4 and C2+ FEs of 82% and 91.7% in a flow cell at a current density of 400 mA cm-2 in 1 M KOH. In situ characterizations and theoretical calculations reveal that the active interfaces facilitate CO2 activation and lower the formation energy of the key intermediate *OCCOH, thus promoting CO2 conversion to C2+. This work provides a rational design for steering the active sites toward C2+ products.

Fabrication of Zn-Air Battery with High Output Capacity Under Ultra-Large Current

Zn-air battery (ZAB) is advocated as a more viable option in the new-energy technology. However, the limited-output capacity at a high current density impedes the driving range in power batteries substantially. Here, a novel heterojunction-based graphdiyne (GDY) and Ag29Cu7 alloy quantum dots (Ag29Cu7 QDs/GDY) for constructing a high-performance aqueous ZAB are fabricated. The as-fabricated ZAB achieves discharge at up to 100 mA cm-2 (the highest value ever reported) along with a remarkable output specific capacity of 786.2 mAh g-1 Zn, which is mainly benefitted from the binary-synergistic effect toward a stable triple-phase interface for air electrode induced by the Ag29Cu7 QDs and GDY in harsh base, together with the decreasing reaction energy barrier and polarization. The results outperform the superior reports discharging at low current and will bring breakthrough progress toward the practical applications of ZAB on large power supply facilities.

Spatially and Temporally Resolved Dynamic Response of Co-Based Composite Interface during the Oxygen Evolution Reaction

Interfacial interaction dictates the overall catalytic performance and catalytic behavior rules of the composite catalyst. However, understanding of interfacial active sites at the microscopic scale is still limited. Importantly, identifying the dynamic action mechanism of the "real" active site at the interface necessitates nanoscale, high spatial-time-resolved complementary-operando techniques. In this work, a Co3O4 homojunction with a well-defined interface effect is developed as a model system to explore the spatial-correlation dynamic response of the interface toward oxygen evolution reaction. Quasi in situ scanning transmission electron microscopy-electron energy-loss spectroscopy with high spatial resolution visually confirms the size characteristics of the interface effect in the spatial dimension, showing that the activation of active sites originates from strong interfacial electron interactions at a scale of 3 nm. Multiple time-resolved operando spectroscopy techniques explicitly capture dynamic changes in the adsorption behavior for key reaction intermediates. Combined with density functional theory calculations, we reveal that the dynamic adjustment of multiple adsorption configurations of intermediates by highly activated active sites at the interface facilitates the O-O coupling and *OOH deprotonation processes. The dual dynamic regulation mechanism accelerates the kinetics of oxygen evolution and serves as a pivotal factor in promoting the oxygen evolution activity of the composite structure. The resulting composite catalyst (Co-B@Co3O4/Co3O4 NSs) exhibits an approximately 70-fold turnover frequency and 20-fold mass activity than the monomer structure (Co3O4 NSs) and leads to significant activity (η10 ∼257 mV). The visual complementary analysis of multimodal operando/in situ techniques provides us with a powerful platform to advance our fundamental understanding of interfacial structure-activity relationships in composite structured catalysts.

Boosting Electrocatalytic Ammonia Synthesis via Synergistic Effect of Iron-Based Single Atoms and Clusters

Electrocatalytic reduction of nitrate to ammonia (NO3RR) is gaining attention for low carbon emissions and environmental protection. However, low ammonia production rate and poor selectivity have remained major challenges in this multi-proton coupling process. Herein, we report a facile strategy toward a novel Fe-based hybrid structure composed of Fe single atoms and Fe3C atomic clusters that demonstrates outstanding performance for synergistic electrocatalytic NO3RR. By operando synchrotron Fourier transform infrared spectroscopy and theoretical computation, we clarify that Fe single atoms serve as the active site for NO3RR, while Fe3C clusters facilitate H2O dissociation to provide protons (*H) for continued hydrogenation reactions. As a result, the Fe-based electrocatalyst exhibits ammonia Faradaic efficiency of nearly 100%, with a corresponding production rate of 24768 μg h-1 cm-2 at -0.4 V vs RHE, exceeding most reported metal-based catalysts. This research provides valuable guidance toward multi-step reactions.

Precise Interstitial Built-In Electric Field Tuning for Hydrogen Evolution Electrocatalysis

The built-in electric field (BEF) has become an effective means of adjusting the electronic structure and hydrogen spillover to influence the adsorption of intermediates. However, the previously reported BEF cannot be tuned continuously and precisely. Herein, a series of nanocatalysts with interstitial BEF were successfully synthesized, and the effect of precisely tuned interstitial BEF on the intermediate's adsorption and hydrogen spillover was systematically investigated using changing the insertion of interstitial B. Three catalysts with different BEF strengths were obtained by changing the interstitial content (B0.22-Cu/NC, B0.30-Cu/NC, B0.41-Cu/NC), and it was demonstrated that B0.30-Cu/NC gave the best catalytic performance for hydrogen evolution reactions (HERs). The turnover frequency (TOF) value is shown to reach 0.36 s-1 at just -0.1 V vs. RHE, which is about 3 times that of Cu (0.12 s-1). For the HER, it is one of the best Cu-based catalysts reported to date (Table S3). Besides, when the catalyst was applied to the cathode of the PEM water electrolyzer, B0.30-Cu/NC exhibited long-time stability at a water-splitting current density of 500 mA cm-2. Density functional theory and in situ Raman spectroscopy suggest that a suitable interstitial BEF can not only optimize the intermediate's adsorption but also promote hydrogen spillover.

Electronic Phosphide-Support Interactions in Carbon-Supported Molybdenum Phosphide Catalysts Derived from Metal-Organic Frameworks

Interfacial interaction in carbon-supported catalysts can offer geometric, electronic, and compositional effects that can be utilized to regulate catalytically active sites, while this is far from being systematically investigated in carbon-supported phosphide catalysts. Here, we proposed a novel concept of electronic phosphide-support interaction (EPSI), which was confirmed by using molybdenum phosphide (MoP) supported on nitrogen-phosphorus codoped carbon (NPC) as a model catalyst (MoP@NPC). Such a strong EPSI could not only stabilize MoP in a low-oxidation state under environmental conditions but also regulate its electronic structure, leading to reduced dissociation energy of the oxygen-containing intermediates and enhancing the catalytic activity for oxidative desulfurization. The removal of dibenzothiophene over the MoP@NPC was as high as 100% with a turnover frequency (TOF) value of 0.0027 s-1, which was 33 times higher than that of MoP without EPSI. This work will open new avenues for the development of high-performance supported phosphide catalysts.

A Low-Strain Cathode by sp-Carbon Induced Conversion in Multi-Level Structure of Graphdiyne

A multi-level architecture formed alternatively by the conformal graphdiyne (GDY) and CuS is well engineered for Li-free cathode. Such a proof-of-concept architecture efficiently integrates the advantages of GDY and produces new functional heterojunctions (sp-C-S-Cu hybridization bond). The layer-by-layer 2D confinement effect successfully avoids structural collapse, the selective transport inhibits the shuttling of active components, and the interfacial sp-C-S-Cu hybridization bond significantly regulates the phase conversion reaction. Such new sp-C-S-Cu hybridization of GDY greatly improves the reaction dynamics and reversibility, and the cathode delivers an energy density of 934 Wh kg-1 and an unattenuated lifespan of 3000 cycles at 1 C. Our results indicate that the GDY-based interface strategy will greatly promote the efficient utilization of the conversion-type cathodes.

Two-Dimensional Carbon Graphdiyne: Advances in Fundamental and Application Research

Graphdiyne (GDY), a rising star of carbon allotropes, features a two-dimensional all-carbon network with the cohybridization of sp and sp² carbon atoms and represents a trend and research direction in the development of carbon materials. The sp/sp²-hybridized structure of GDY endows it with numerous advantages and advancements in controlled growth, assembly, and performance tuning, and many studies have shown that GDY has been a key material for innovation and development in the fields of catalysis, energy, photoelectric conversion, mode conversion and transformation of electronic devices, detectors, life sciences, etc. In the past ten years, the fundamental scientific issues related to GDY have been understood, showing differences from traditional carbon materials in controlled growth, chemical and physical properties and mechanisms, and attracting extensive attention from many scientists. GDY has gradually developed into one of the frontiers of chemistry and materials science, and has entered the rapid development period, producing large numbers of fundamental and applied research achievements in the fundamental and applied research of carbon materials. For the exploration of frontier scientific concepts and phenomena in carbon science research, there is great potential to promote progress in the fields of energy, catalysis, intelligent information, optoelectronics, and life sciences. In this review, the growth, self-assembly method, aggregation structure, chemical modification, and doping of GDY are shown, and the theoretical calculation and simulation and fundamental properties of GDY are also fully introduced. In particular, the applications of GDY and its formed aggregates in catalysis, energy storage, photoelectronic, biomedicine, environmental science, life science, detectors, and material separation are introduced.