Construction of In2S3@NH2-MIL-68(In)@In2S3 Sandwich Homologous Heterojunction for Efficient CO2 Photoreduction

Carbon Dioxide Capture and Conversion Using Metal-Organic Framework (MOF) Materials: A Comprehensive Review

The escalating threat of anthropogenic climate change has spurred an urgent quest for innovative CO2 capture and utilization (CCU) technologies. Metal-organic frameworks (MOFs) have emerged as prominent candidates in CO2 capture and conversion due to their large specific surface area, well-defined porous structure, and tunable chemical properties. This review unveils the latest advancements in MOF-based materials specifically designed for superior CO2 adsorption, precise separation, advanced photocatalytic and electrocatalytic CO2 reduction, progressive CO2 hydrogenation, and dual functionalities. We explore the strategies that enhance MOF efficiency and examine the challenges of and opportunities afforded by transitioning from laboratory research to industrial application. Looking ahead, this review offers a visionary perspective on harnessing MOFs for the sustainable capture and conversion of CO2.

Rational Design of MIL-68(In) Derived Multiple Sulfides with Well Confined Quantum Dots and the Promoted Photocatalytic Hydrogen Generation

Quantum dots (QDs) of metal sulfides were proven to be excellent cocatalysts in visible-light-driven photocatalytic reactions. Metal organic frameworks (MOFs) possess a 3D porous channel that effectively confines small QDs and preserves their high catalytic activity by preventing their aggregation. In order to precisely construct the ternary metal sulfides of ZnS/ZnIn2S4/In2S3 with well-maintained Zn-AgInS2 (ZAIS) QDs, an in situ sulfurization combining a subsequent Zn(II)-exchange strategy was employed in this work. First, the ZAIS QDs were incorporated into MIL-68(In), which were then used as the precursors to precisely construct the ternary metal sulfides of ZnS/ZnIn2S4/In2S3 with well maintained ZAIS QDs through an in situ sulfurization combining subsequent Zn(II)-exchange strategy. When the optimized nanocomposites (QDs@M-t-Zn, where t is the sulfurization time) were applied in visible light-induced photocatalytic hydrogen generation, the resulting QDs@M-24h-Zn showed a significantly improved hydrogen evolution rate of 448.96 μmol g-1 h-1, which values are clearly higher than those of MIL-68(In), QDs@MIL-68(In), and M-24h-Zn without the presence of ZAIS QDs. To elucidate the increased photocatalytic mechanism, the optical patterns and the batch electrochemical investigations were combined. It has been discovered that the matching band potentials and the close contact heterojunction enhance interface charge transfer, which in turn encourages photocatalytic hydrogen production. This study demonstrates the well-thought-out design of the uniform confinement architecture inherited from MOF QD-assisted multinary metal sulfides photocatalysts.

Rich oxygen vacancies in confined heterostructured TiO2@In2S3 hybrid for boosting solar-driven CO2 reduction

Solar energy driving CO2 reduction is a potential strategy that not only mitigates the greenhouse effect caused by high CO2 level in atmosphere, but also yields carbon chemicals/fuels at the same time. Herein, a facile way to design the heterogeneous TiO2@In2S3 hollow structures possessing robust light harvesting in both ultraviolet and visible regions is proposed and exhibits a higher generation rate of 25.35 and 1.24 μmol·g-1·h-1 for photocatalytic CO2 reduction to CO and CH4, respectively. The excellent photocatalytic catalytic performance comes from i) the confined heterostructured TiO2@In2S3 possesses a suitable band structure and a broadband-light absorbing capacity for CO2 photoreduction, ii) the rich interfaces between nanosized TiO2 and In2S3 on the shell can significantly reduce the diffusion length of carriers and enhance the utilization efficiency of photogenerated electron-hole pairs, and iii) enriched surface oxygen vacancies can provide more active sites for CO2 adsorption.

Engineering highly dispersed AgI nanoparticles on hierarchical In2S3 hollow nanotube to construct Z-scheme heterojunction for efficient photodegradation of insecticide imidacloprid

Increasing the exposure of active sites and improving the intrinsic activity are necessary considerations for designing a highly efficient photocatalyst. Herein, an In2S3/AgI stable Z-scheme heterojunction with highly dispersed AgI nanoparticles (NPs) is synthesized by the mild self-templated and in-situ ion exchange strategy. Impressively, the optimized In2S3/AgI-300 Z-scheme heterojunction exhibits superior photodegradation activity (0.020 min-1) for the decomposition of insecticide imidacloprid (IMD), which is extremely higher than that of pure In2S3 (0.002 min-1) and AgI (0.013 min-1). Importantly, the three-dimensional excitation-emission matrix (3D EEMs) fluorescence spectra, high-resolution mass spectrometry (HRMS), the photoelectrochemical tests, radical trapping experiment, and electron spin resonance (ESR) technique are performed to clarify the possible degradation pathway and mechanism of IMD by the In2S3/AgI-300 composite. The enhanced photocatalytic performance is attributed to the highly dispersed AgI NPs on hierarchical In2S3 hollow nanotube and the construction of In2S3/AgI Z-scheme heterojunction, which can not only increase active site exposure, but also improve its intrinsic activity, facilitating rapid charge transfer rate and excellent electron-hole pairs separation efficiency. Meanwhile, the practical application potential of the In2S3/AgI-300 composite is systematically investigated. This study opens a new insight for designing catalysts with high photocatalytic performance through a convenient approach.

Urchin-like band-matched Fe2O3@In2S3 hybrid as an efficient photocatalyst for CO2 reduction

Herein, an urchin-like Fe₂O₃@In₂S₃ hybrid composite is designed and synthesized using a facile process. The composite efficiently harvests light in both the ultraviolet and visible regions, and the unique hierarchical structure provides several advantages for photocatalytic applications: (i) a suitable band-matching structure and broadband-light absorbing capacity enable the reduction of CO₂ into hydrocarbon, (ii) the extensive network of interfacial contact between nano-sized Fe₂O₃ and In₂S₃ significantly increases the separation of charge carriers and enhances the utilization of photogenerated electron-hole pairs, and (iii) an abundance of surface oxygen vacancies provide numerous active sites for CO₂ molecule adsorption. The optimized Fe₂O₃@In₂S₃ composite generated CO from the photocatalytic reduction of CO₂ at a rate of 42.83 μmol·g^-1·h^-1, and no signs of deactivation were observed during continued testing for 32 h under 300 W Xe lamp irradiation.

The Advanced Synthesis of MOFs-Based Materials in Photocatalytic HER in Recent Three Years

Since the advent of metal–organic frameworks (MOFs), researchers have paid extensive attention to MOFs due to their determined structural composition, controllable pore size, and diverse physical and chemical properties. Photocatalysis, as a significant application of MOFs catalysts, has developed rapidly in recent years and become a research hotspot continuously. Various methods and approaches to construct and modify MOFs and their derivatives can not only affect the structure and morphology, but also largely determine their properties. Herein, we summarize the advanced synthesis of MOFs-based materials in the field of the photocatalytic decomposition of water to produce hydrogen in the recent three years. The main contents include the overview of the novel synthesis strategies in four aspects: internal modification and structure optimization of MOFs materials, MOFs/semiconductor composites, MOFs/COFs-based hybrids, and MOFs-derived materials. In addition, the problems and challenges faced in this direction and the future development goals were also discussed. We hope this review will help deepen the reader’s understanding and promote continued high-quality development in this field.

Recent Progress of Metal Sulfide Photocatalysts for Solar Energy Conversion

Artificial photosynthetic solar-to-chemical cycles enable an entire environment to operate in a more complex, yet effective, way to perform natural photosynthesis. However, such artificial systems suffer from a lack of well-established photocatalysts with the ability to harvest the solar spectrum and rich catalytic active-site density. Benefiting from extensive experimental and theoretical investigations, this bottleneck may be overcome by devising a photocatalytic platform based on metal sulfides with predominant electronic, physical, and chemical properties. These tunable properties can endow them with abundant active sites, favorable light utilization, and expedited charge transportation for solar-to-chemical conversion. Here, it is described how some vital lessons extracted from previous investigations are employed to promote the further development of metal sulfides for artificial photosynthesis, including water splitting, CO₂ reduction, N₂ reduction, and pollutant removal. Their functions, properties, synthetic strategies, emerging issues, design principles, and intrinsic functional mechanisms for photocatalytic redox reactions are discussed in detail. Finally, the associated challenges and prospects for the utilization of metal sulfides are highlighted and future development trends in photocatalysis are envisioned.

The state of the art review on photocatalytic Cr(VI) reduction over MOFs-based photocatalysts: From batch experiment to continuous operation

This state of the art review presented the photocatalytic reduction from highly toxic Cr(VI) to lowly toxic Cr(III) with metal-organic frameworks (MOFs) and their composites. The construction of composites facilitated the transportation of the photo-induced charges to enhance the Cr(VI) reduction, in which the corresponding mechanisms were clarified by both experimental tests and DFT calculations. The immobilized MOFs onto some substrates accomplished continuous operations toward Cr(VI) reduction even under real solar light. As well, the environmental applications of the Cr(VI) reduction were analyzed, in which the influence factors toward the Cr(VI) reduction were clarified. This review reported that a big breakthrough was achieved from the batch experiment to the continuous operation for Cr(VI) reduction, in which MOFs demonstrated a bright prospective in the field of photocatalytic Cr(VI) reduction.

An in situ derived MOF@In2S3 heterojunction stabilizes Co(II)-salicylaldimine for efficient photocatalytic formic acid dehydrogenation

We report here the hierarchical construction of a molecular Co(II)-salicylaldimine catalyst and an in situ derived In₂S₃ semiconductor in a MOF@In₂S₃ heterojunction through sequentially controllable in situ etching and post-synthetic modification for photocatalytic hydrogen production from formic acid. The enhanced catalyst stability and facilitated charge carrier mobility between the In₂S₃ photosensitizers and Co catalyst realize a superior H₂ production rate of 18 746 μmol g^-1 h^-1 (selectivity > 99.9%) with a turnover number (TON) of up to 6146 in 24 h (apparent quantum efficiency of 3.8% at 420 nm), indicating a 165-fold enhancement over that of the pristine MOF. This work highlights a powerful strategy for synergistic Earth-abundant metal-based MOF photocatalysis in promoting H₂ production from FA.

Rationally constructed ZnCdS-HDCs@In2S3-HNRs double-hollow heterojunction with promoted light capture capability for photoelectrochemical biosensing

The construction of novel heterojunction is regarded as an operative scheme to promote the transport of photogenerated carriers and reduce electron-hole pair recombination to enhance the photoelectrochemical (PEC) performances. Herein, ZnCdS hollow dodecahedral nanocages (ZnCdS-HDCs) and In₂S₃ hollow nanorods (In₂S₃-HNRs), which were derived from two different of metal-organic frameworks (MOFs) by solvothermal sulfidation method and were constructed an original double-hollow heterostructure ZnCdS-HDCs@In₂S₃-HNRs. The intrinsic mechanism of In₂S₃-HNRs benefiting from unique morphology to boost the photochemical properties under visible light irradiation was illustrated. Meanwhile, the mechanism of the novel type II heterojunction with staggered matching levels was revealed, which could effectively restrict electron-hole pair reassociation separation, and accelerated charge separation and transfer. Therefore, based on the excellent PEC performance of ZnCdS- HDCs@In₂S₃-HNRs double-hollow heterostructure, a signal-off PEC biosensor platform without labeled was constructed for the detection of CA15-3, which manifested acceptable specificity, reproducibility and stability. Additionally, the expected PEC biosensors showed a linear response range from 1.0 × 10^-5 to 10 U·mL^-1 in addition to an ultralow detection limit of 3.78 × 10^-6 U·mL^-1. This study innovatively constructed and prepared a new double-hollow heterojunction material with superior PEC nature for the application of PEC biosensing, which exhibits a broad application prospect.

Fire retardant, UV and blue light double-blocking super clear Carboxymethylated cellulose bioplastics enabled by metal organic framework

It is still a challenge to realize super clear cellulose-based film materials with different functional combinations. This study presents a novel concept of fabricating flame-retardant, mechanically strong, UV and blue light double-blocking carboxymethylated cellulose-based nanocomposite bioplastics enabled by nano-metal organic framework (MIL-125(Ti)-NH₂). Carboxymethylated cellulose gel with porous structure acts as nanoreactor and carboxyl groups as reactive sites to facilitate the growth and anchorage of nano-MIL-125(Ti)-NH₂. Super clear bioplastics were obtained through hot-pressing. The results show that the neat carboxymethylated cellulose bioplastic possesses high transmittance (94.1% at 600 nm) and low haze (2.0% at 600 nm). The incorporation of nano-MIL-125(Ti)-NH₂ enabled nanocomposite bioplastics to obtain UV and blue light double-shielding capability meanwhile retaining high transmittance (79-92.8%) and low haze (2.6-7.2%). Moreover, the incorporation of nano-MIL-125(Ti)-NH₂ was found to significantly improve the mechanical strength and decrease the flammability of nanocomposite bioplastics. This facile strategy would direct nanocomposite bioplastics toward diversified applications.

MOFs-Derived Fusiform In2 O3 Mesoporous Nanorods Anchored with Ultrafine CdZnS Nanoparticles for Boosting Visible-Light Photocatalytic Hydrogen Evolution

The development of efficient visible-light-driven photocatalysts is one of the critically important issues for solar hydrogen production. Herein, high-efficiency visible-light-driven In₂ O₃ /CdZnS hybrid photocatalysts are explored by a facile oil-bath method, in which ultrafine CdZnS nanoparticles are anchored on NH₂ -MIL-68-derived fusiform In₂ O₃ mesoporous nanorods. It is disclosed that the as-prepared In₂ O₃ /CdZnS hybrid photocatalysts exhibit enhanced visible-light harvesting, improves charges transfer and separation as well as abundant active sites. Correspondingly, their visible-light-driven H₂ production rate is significantly enhanced for more than 185 times to that of pristine In₂ O₃ nanorods, and superior to most of In₂ O₃ -based photocatalysts ever reported, representing their promising applications in advanced photocatalysts.