Bioengineering of one dimensional hierarchical Cu7S4 hollow nanotubes for non-enzymatic glucose sensing applications

Herein, a novel and facile eco-friendly green chemistry approach has been devised at room temperature for synthesis of 1D hierarchical Cu7S4 hollow nanotubes on Cu substrate via volatile organosulfur compounds from Allium sativum L for non-enzymatic glucose detection. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and X-ray spectroscopy (XPS) were employed to characterize the surface morphology, structural phase, compositional, and chemical states of the obtained samples, respectively. The SEM results confirm the formation of 1D hierarchical Cu7S4 hollow nanotubes. The XRD patterns are indexed to orthogonal anilite Cu7S4 crystal planes and the EDX spectra clearly reveal the presence of Cu and S elements. XPS spectra confirms peaks of Cu 2p and S 1s core levels, which are typical characteristics of Cu(i) and S(ii), respectively. The Brunauer-Emmett-Teller (BET) specific surface area for obtained Cu7S4 hollow nanotubes is 2.07 m2 g-1 with a pore size distribution of 27.90 nm. Using Cu7S4 hollow nanotubes, the detection of non-enzymatic glucose was conducted over a dynamic range of concentrations from 0.5 to 100 μmol L-1 and reveals a high sensitivity of 1058.33 μA mM-1cm-2 and a limit of detection (LOD) of 0.127 μmol L-1. The obtained results indicated that Cu7S4 hollow nanotubes are promising candidates for non-enzymatic glucose detection.

Phosphorus incorporation accelerates ammonia electrosynthesis over a mesoporous Au film

In this work, a phosphorus-doped mesoporous Au alloy film is grown on Ni foam (mAuP/NF) via a replacement reaction using diblock copolymers and NaH₂PO₂ as pore-forming agents and a phosphorus dopant, respectively. Due to the phosphorus doping and well-developed mesoporous structure, the obtained mAuP/NF possesses superior NH₃ yield (36.52 µg h^-1 mg^-1_cat.) and faradaic efficiency (20.32%) for ammonia electrosynthesis in neutral conditions, superior to mAu/NF.

Emerging interstitial/substitutional modification of Pd-based nanomaterials with nonmetallic elements for electrocatalytic applications

Palladium (Pd)-based nanomaterials have been identified as potential candidates for various types of electrocatalytic reaction, but most of them typically exhibit unsatisfactory performances. Recently, extensive theoretical and experimental studies have demonstrated that the interstitial/substitutional modification of Pd-based nanomaterials with nonmetallic atoms (H, B, C, N, P, S) has a significant impact on their electronic structure and thus leads to the rapid development of one kind of promising catalyst for various electrochemical reactions. Considering the remarkable progress in this area, we highlight the most recent progress regarding the innovative synthesis and advanced characterization methods of nonmetallic atom-doped Pd-based nanomaterials and provide insights into their electrochemical applications. What's more, the unique structure- and component-dependent electrochemical performance and the underlying mechanisms are also discussed. Furthermore, a brief conclusion about the recent progress achieved in this field as well as future perspectives and challenges are provided.

Phosphorus modulation of a mesoporous rhodium film for enhanced nitrogen electroreduction

Electrochemical reduction of nitrogen to ammonia has received considerable attention for sustainable nitrogen fixation, but the sluggish kinetics results in unsatisfactory activity and efficiency. Designing electrocatalytic active centers for nitrogen adsorption and activation is highly desired. Herein, we present an electrodeposition method for the synthesis of a phosphorus-doped mesoporous rhodium film on nickel foam for the electrochemical synthesis of ammonia. Due to the unique combination of components and structure, the obtained catalyst not only shows excellent catalytic performance (NH₃ yield: 32.57 μg h^-1 mg^-1_cat.; faradaic efficiency: 40.86%), but also exhibits almost no decrease in activity after the durability test. This research work can provide a facile synthesis strategy for non-metal-doped porous metal based catalysts, which would be promising for the electrochemical synthesis of ammonia.

Rapid Synthesis of Large-Size Fe2O3 Nanoparticle Decorated NiO Nanosheets via Electrochemical Exfoliation for Enhanced Oxygen Evolution Electrocatalysis

A novel nonprecious Fe₂O₃ nanoparticle decorated NiO nanosheet (Fe₂O₃ NPs@NiO NSs) composite has been obtained by a rapid one-pot electrochemical exfoliation method and can be used as an efficient oxygen evolution reaction (OER) catalyst. In the nanocomposite, the Fe₂O₃ NPs are uniformly anchored on the ultrathin graphene-like NiO nanosheets. At the same time, we also studied the influence of the Fe/Ni molar ratio on the morphology and catalytic activity. The Fe₂O₃ NPs@NiO NSs nanocomposite possessed a high BET surface area (194.1 m² g^-1), which is very conducive to the charge/mass transfer of electrolyte ions and O₂. Owing to the unique two-dimensional (2D) heterostructures and rational Fe content, the as-prepared Fe₂O₃ NPs@NiO NSs show high catalytic performance, a low overpotential at 10 mA cm^-2 (221 mV), a small Tafel slope (53.4 mV dec^-1), and 2000 cycle and 20 h long-term durability. The introduction of Fe₂O₃ NPs is beneficial to accelerating charge transport, increasing the electrochemically active surface area (ECSA), and thus improving the release of oxygen bubbles from the electrode surface.

B-Doped PdRu nanopillar assemblies for enhanced formic acid oxidation electrocatalysis

Adjusting the morphology and composition of Pd-based materials is a promising strategy to improve their performance for the electrocatalytic formic acid oxidation reaction (FAOR). In this work, we report the preparation of B-doped PdRu nanopillar assemblies (B-PdRu NPAs) by a two-step method using NaBH4 as the boron dopant. On combining the hyper-branched structure and the multi-component synergistic effect, B-PdRu NPAs achieve a high mass activity of 1.09 mA μg-1Pd for the FAOR and retain 73.19% of the initial activity after 500 cycles, which is superior to undoped counterparts. The proposed synthesis strategy provides a simple method for the synthesis of metal-nonmetal nanomaterials with desired composition and design structure for electrocatalytic fields.

Three-dimensional Pd-Ag-S porous nanosponges for electrocatalytic nitrogen reduction to ammonia

Electrochemical nitrogen reduction reaction (NRR) provides a facile and sustainable route to synthesize ammonia. The preparation of efficient and high-performance catalysts is one of the most important issues in large-scale applications of the electrochemical synthesis of ammonia. Herein, we have devised a simple method to fabricate three-dimensional palladium-silver-sulphur porous nanosponges (Pd-Ag-S PNSs) under room temperature. The porous network can provide more active sites and accessible channels for the reaction species. The incorporation of sulfur reduces the energy barrier of NRR and promotes the nitrogen hydrogenation to ammonia. Intrinsically, the Pd-Ag-S PNSs demonstrates a superior NRR performance with an NH3 yield of 9.73 μg h-1 mg-1cat. and a faradaic efficiency of 18.41% at -0.2 V, superior to those of the undoped Pd-Ag PNSs. The design of the three-dimensional metallic nanosponges with the doping of nonmetallic elements is a highly valuable strategy for NRR and other electrocatalytic reactions.

Synthesis and characterization of size controlled alloy nanoparticles

Bimetallic and multimetallic alloy nanoparticles are emerging as a class of critical nanomaterials in electronic, optical and magnetic fields due to their unique physic-chemical properties. In particular, precise control of the nanoparticle size can endow them with broad versatility and high selectivity. This chapter reviews some tremendous achievements in the development of size controlled bimetallic and multimetallic alloy nanoparticles, with special emphasis on general preparation methods, characterization methodologies and instrumentation techniques. Some key factors and future perspectives on the development of size-controlled bimetallic and multimetallic alloy nanoparticles are also discussed.

Facile dual tuning of PtPdP nanoparticles by metal-nonmetal co-incorporation and dendritic engineering for enhanced formic acid oxidation electrocatalysis

Tuning the compositions and morphologies of catalysts is very important for the design of efficient formic acid oxidation reaction (FAOR) electrocatalysts. Herein, unique PtPdP dendritic nanoparticles (PtPdP DNs) with uniform size and open-pore structure are fabricated by a facile method, in which the Pd and P elements are simultaneously incorporated into Pt DNs. The prepared PtPdP DNs show enhanced catalytic activity and stability for FAOR. The improved electrocatalytic activity toward FAOR for the PtPdP DNs is mainly attributed to the synergic enhancement effect of the structural and compositional advantages, which jointly promote the electrocatalytic kinetics and thus enhance the electrocatalytic performance.

Highly branched and defect-rich PdP nanosheets for ethanol oxidation electrocatalysis

Highly branched, defect-rich, and ultrathin PdP alloy nanosheets with enhanced electrocatalytic ethanol oxidation reaction (EOR) performance.

Synthesis, growth mechanisms, and applications of palladium-based nanowires and other one-dimensional nanostructures

Palladium-based nanostructures have attracted the attention of researchers due to their useful catalytic properties and unique ability to form hydrides, which finds application in hydrogen storage and hydrogen detection. Palladium-based nanowires have some inherent advantages over other Pd nanomaterials, combining high surface-to-volume ratio with good thermal and electron transport properties, and exposing high-index crystal facets that can have enhanced catalytic activity. Over the past two decades, both synthesis methods and applications of 1D palladium nanostructures have advanced greatly. In this review, we start by discussing different types of 1D palladium nanostructures before moving on to the different synthesis approaches that can produce them. Next, we discuss factors including kinetic vs. thermodynamic control of growth, oxidative etching, and surface passivation that affect palladium nanowire synthesis. We also review efforts to gain insight into growth mechanisms using different characterization tools. We discuss the effects of concentration of capping agents, reducing agents, metal halides, pH, and sacrificial oxidation on the growth of Pd-based nanowires in solution, from shape control, to yield, to aspect ratio. Various applications of palladium and palladium alloy nanowires are then discussed, including electrocatalysis, hydrogen storage, and sensing of hydrogen and other chemicals. We conclude with a summary and some perspectives on future research directions for this category of nanomaterials.

Sonochemical synthesis of high-performance Pd@CuNWs/MWCNTs-CH electrocatalyst by galvanic replacement toward ethanol oxidation in alkaline media

In this paper, a fast and effective method for the palladium (Pd) wire nanostructures synthesis with the great surface area through galvanic replacement reaction utilizing copper nanowires (CuNWS) as a template by the assistance of ultrasound under room temperature condition is proposed. A multifunctional catalyst with the mentioned nanostructure, Pd@CuNWs, and multi walled carbon nanotubes (MWCNTs) and chitosan (CH) as a binder was fabricated. To investigate the morphology and bulk composition of the prepared catalyst, Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Powder Diffraction (XRD), and Inductively Coupled Plasma atomic Emission Spectroscopy (ICP-AES) were utilized. Various electrochemical techniques including chronoamperometry and cyclic voltammetry were employed for the electrocatalytic activity of ethanol electrooxidation and durability in basic solution. Electrochemical catalytic activity and durability evaluation results proved that the as-synthesized Pd@CuNWs/MWCNTs-CH has a super electrocatalytic activity compared to Pd/MWCNTs and Pd/C electrocatalysts for ethanol electrooxidation. Pd@CuNWs/MWCNTs-CH catalyst demonstrated substantially enhanced performance and long-term stability for ethanol electrooxidation in the basic solution in comparison to Pd/MWCNTs and commercial Pd/C demonstrated the potential in utilizing Pd@CuNWs/MWCNTs-CH as an efficient catalyst for ethanol oxidation. Additionally, thermodynamic and kinetic evaluations revealed that the Pd@CuNWs/MWCNTs-CH catalyst has lower activation energy compared to Pd/MWCNTs and Pd/C which leads to a lower energy barrier and an excellent charge transfer rate towards ethanol oxidation. Noticeably, the Pd@CuNWs/MWCNTs-CH presented excellent catalytic activities with high peak current density which was 9.5 times more than Pd/C, and more negative onset potential in comparison to Pd/C is acquired for ethanol electrooxidation denoting synergistic effect between CuNWs/MWCNs-CH and Pd. The Pd@CuNWs/MWCNTs-CH can be considered as a valid candidate among available electrocatalysts in direct ethanol fuel cells (DEFCs).

Preparation and Catalytic Performance of Metal-Rich Pd Phosphides for the Solvent-Free Selective Hydrogenation of Chloronitrobenzene

A facile synthesis method of palladium phosphide supported on the activated carbon was developed. The effects of Pd precursors for phosphatization, phosphatization temperature, and the ratio of hypophosphite/Pd on the generation of palladium phosphide were investigated, and a generation mechanism of the Pd3P crystal structure is proposed. The results demonstrate that only PdO, rather than Pd or PdCl2, can transform into Pd phosphide without damage to the activated carbon. The penetration of P into the Pd particle can dramatically improve the dispersion of Pd species particles on the activated carbon. The generation of Pd phosphide greatly depends on the phosphatization temperature and the ratio of hypophosphite/Pd. An intact Pd3P crystal structure was obtained when the ratio of hypophosphite/Pd reached 32 and the phosphatization temperature was above 400 °C. The Pd3P supported on the activated carbon exhibited superior catalytic performance in terms of the hydrogenation of halonitrobenzenes to haloanilines because it had few L acids and B acids sites and could not generate deficient-electron active hydrogen atoms as electrophiles.

Chemical Design of Palladium-Based Nanoarchitectures for Catalytic Applications

Palladium (Pd) plays an important role in numerous catalytic reactions, such as methanol and ethanol oxidation, oxygen reduction, hydrogenation, coupling reactions, and carbon monoxide oxidation. Creating Pd-based nanoarchitectures with increased active surface sites, higher density of low-coordinated atoms, and maximized surface coverage for the reactants is important. To address the limitations of pure Pd, various Pd-based nanoarchitectures, including alloys, intermetallics, and supported Pd nanomaterials, have been fabricated by combining Pd with other elements with similar or higher catalytic activity for many catalytic reactions. Herein, recent advances in the preparation of Pd-based nanoarchitectures through solution-phase chemical reduction and electrochemical deposition methods are summarized. Finally, the trend and future outlook in the development of Pd nanocatalysts toward practical catalytic applications are discussed.

Ir-Alloyed Ultrathin Ternary PdIrCu Nanosheet-Constructed Flower with Greatly Enhanced Catalytic Performance toward Formic Acid Electrooxidation

Ternary metal-element alloys have been reported as efficient electrocatalysts toward various electrochemical reactions, but a unique three-dimensional (3D) Ir-alloyed ternary nanosheet-composed flower (NCF) structure has not been explored yet. Herein, an innovated 1.8 nm Ir-alloyed ultrathin ternary PdIrCu NCF structure is synthesized via one-pot solvothermal reduction without using any surfactant. The as-prepared PdIrCu/C NCF catalyst remarkably improves the stability than commercial Pd/C toward formic acid electrooxidation while resulting in significantly increased mass activity. The improvement of electrocatalytic properties depends on the introduction of Ir and Cu atoms, which greatly prevented poisoning from CO while modifying the electronic structure of Pd for increased reaction active sites and accelerated charge-transfer rate as well as facilitated mass transport by ultrathin NCF 3D structure. Therefore, this catalyst possesses a promising application prospect in electrochemical energy storage/conversion systems.

Discovery of Hexagonal Structured Pd-B Nanocrystals

We report on hexagonal close-packed (hcp) palladium (Pd)-boron (B) nanocrystals (NCs) by heavy B doping into face-centered cubic (fcc) Pd NCs. Scanning transmission electron microscopy-electron energy loss spectroscopy and synchrotron powder X-ray diffraction measurements demonstrated that the B atoms are homogeneously distributed inside the hcp Pd lattice. The large paramagnetic susceptibility of Pd is significantly suppressed in Pd-B NCs in good agreement with the reduction of density of states at Fermi energy suggested by X-ray absorption near-edge structure and theoretical calculations.

Mechanism of palladium(ii) biosorption by Providencia vermicola

Palladium uptake process, multi-scale visualization and functional groups of Providencia vermicola biomass in palladium biosorption were analyzed for the first time.

Facile synthesis of Pd-decorated Pt/Ru networks with highly improved activity for methanol electrooxidation in alkaline media

Electrocatalytic activity toward methanol oxidation is greatly enhanced after partial replacement of Ru with Pd in Pt/Ru/Pd networks.

The green synthesis of ultrafine palladium–phosphorus alloyed nanoparticles anchored on polydopamine functionalized graphene used as an excellent electrocatalyst for ethanol oxidation

A new catalyst, consisting of ultrafine Pd–P alloyed nanoparticles (NPs) anchored on polydopamine functionalized graphene (Pd–P/PDA-GS), was fabricated by a green, facile and surfactant free method for ethanol electrocatalytic oxidation reaction (EOR).

A phosphorus–carbon framework over activated carbon supported palladium nanoparticles for the chemoselective hydrogenation of para-chloronitrobenzene

A novel Pd–P–C framework structure was fabricated. Pd with electron-rich properties exhibits superior selectivity up to 99.9% for the hydrogenation of p-CNB to p-CAN.

Fabrication of Pd/P nanoparticle networks with high activity for methanol oxidation

The as-prepared Pd/P nanoparticle networks efficiently exhibit electrocatalytic activity and stability for methanol oxidation.

A porous ternary PtPdCu alloy with a spherical network structure for electrocatalytic methanol oxidation

A porous ternary alloy Pt₅PdCu₅ was prepared, which exhibits a unique spherical network structure with a high specific surface area of 86.9 m² g⁻¹ and enhanced electrocatalytic activity towards methanol oxidation.

Facile synthesis of Pd/PDDA-GN/PMo11Co composite and its enhanced catalytic performance for formic acid oxidation

The PMo₁₁Co into the composite Pd/PDDA-GN/PMo₁₁Co contributes to converting intermediate species CO into CO₂ for formic acid oxidation.

Electrically conducting palladium selenide (Pd4Se, Pd17Se15, Pd7Se4) phases: synthesis and activity towards hydrogen evolution reaction

Electrically conducting, continuous films of different phases of palladium selenides are synthesized by the thermolysis of single source molecular precursors.

Novel Pd-catalyzed electroless Au deposition method using a sulfite solution

A novel method is reported for the electroless deposition of Au using nanoscale Pd catalysts in a sulfite solution. A uniform and high quality Au film was generated.

A highly active Pd–P nanoparticle electrocatalyst for enhanced formic acid oxidation synthesized via stepwise electroless deposition

A highly active Pd–P nanoparticle electrocatalyst for formic acid oxidation was synthesized using NaH₂PO₂ as the reducing agent.

Green synthesis of PdCu supported on graphene/polyoxometalate LBL films for high-performance formic acid oxidation

PdCu alloy nanaoparticles (with sizes of ca. 4.5 nm) have been synthesized by a one-step electrochemical process on composite films constructed from functionalized graphene (GN) and H₃PMo₁₂O₄₀ (PMo₁₂) by LBL assembly.

A facilely synthesized highly active Pd nanoparticle electrocatalyst for electroless deposition process

Pd nanoparticles chemically synthesized by respective reducing agents were evaluated in the hypophosphite oxidation reaction for initiating electroless Ni deposition.

Synthesis of dendritic Pt–Ni–P alloy nanoparticles with enhanced electrocatalytic properties

Dendritic Pt–Ni–P nanoparticles were synthesizedviaa wet-chemical route, exhibiting a higher electrocatalytic activity than dendritic Pt–Ni nanoparticles and commercial Pt/C.

Room-temperature synthesis with inert bubble templates to produce “clean” PdCoP alloy nanoparticle networks for enhanced hydrazine electro-oxidation

PdCoP alloy nanoparticle networks prepared using inert bubbles as template exhibited high activity for hydrazine oxidation.

Amorphous PtNiP particle networks of different particle sizes for the electro-oxidation of hydrazine

Amorphous PtNiP particle networks with different particle sizes prepared via the reaction temperature control method showed high catalytic activity for hydrazine oxidation compared to the Pt and PtNi catalysts due to its porous, amorphous structure.

Gas–liquid interface-mediated room-temperature synthesis of “clean” PdNiP alloy nanoparticle networks with high catalytic activity for ethanol oxidation

PdNiP alloy nanoparticle networks prepared via a gas–liquid interface reaction had markedly high activity and durability for ethanol oxidation.