Hydrogen Production Activity Research Articles

Construction of Cu2MoS4/ZnO Heterostructures and Mechanism of Photocatalytic Hydrogen Production.

Constructing wide and narrow band gap heterogeneous semiconductors is a method to improve the activity of photocatalysts. In this paper, CMS/ZnO heterojunctions were prepared by solvothermal loading of ZnO particles on the surface of Cu2MoS4 nanosheets. The photocatalytic H2 precipitation rate is about 545 μmol·g-1·h-1, which is 6.8 times that of Cu2MoS4 and 3 times that of ZnO without any cocatalyst. After etching modification of CMS, the photocatalytic hydrogen production efficiency of the ECMS/ZnO heterojunction is further improved. Its hydrogen production efficiency reaches about 1115 μmol·g-1·h-1, which is 9 times that of ECMS and 6 times that of ZnO. The reasons are mainly attributed to the following two factors: (1) the formation of the ECMS/ZnO type-II-type heterojunction facilitates the effective separation of photogenerated electrons and holes; (2) the band structure of Cu2MoS4 was optimized by etching modification, which made the ECMS/ZnO heterojunction have lower interfacial charge transfer resistance and improved the photocatalytic hydrogen production activity of the heterojunction.

Effect of Calcination-Induced Oxidation on the Photocatalytic H2 Production Performance of Cubic Cu2O/CuO Composite Photocatalysts

This study explores the H2 production performance of CuO/Cu2O with different morphology (nanocubes) synthesized by different methods using different sacrificial reagent (lactic acid), compared with the other three reported CuO/Cu2O photocatalysts used for H2 production. A cubic Cu2O photocatalyst was prepared using a hydrothermal method. It was then calcined at a certain temperature to form a cubic Cu2O/CuO composite photocatalyst. XRD, TEM, and XPS spectra confirmed the successful synthesis of cubic Cu2O/CuO composite photocatalysts by calcination-induced oxidation at a certain temperature. As the calcination temperature increases, the crystal phase of the photocatalyst changes from Cu2O to Cu2O/CuO and then to CuO. The effects of calcination-induced oxidation on morphology, light absorption, the separation of photoexcited carriers, and the H2 production activity of photocatalysts were studied. EPR spectra were monitored to analyze the oxygen vacancies in different samples. Mott–Schottky and Tauc plots were utilized to establish the band structure of the composite photocatalyst. Cu2O/CuO is a type II photocatalyst with a heterogeneous structure that helps to improve electron–hole separation efficiency. The H2 production efficiency of Cu2O/CuO composite photocatalyst reaches 11,888 μmol h−1g−1, 1.6 times that of Cu2O. The formation of the Cu2O/CuO heterojunction leads to enhanced light absorption, charge separation, and hydrogen production activity.

Manipulating Trimetal Catalytic Activities for Efficient Urea Electrooxidation-Coupled Hydrogen Production at Ampere-Level Current Densities.

Replacing the oxygen evolution reaction (OER) with the urea oxidation reaction (UOR) in conjunction with the hydrogen evolution reaction (HER) offers a feasible and environmentally friendly approach for handling urea-rich wastewater and generating energy-saving hydrogen. However, the deactivation and detachment of active sites in powder electrocatalysts reported hitherto present significant challenges to achieving high efficiency and sustainability in energy-saving hydrogen production. Herein, a self-supported bimetallic nickel manganese metal-organic framework (NiMn-MOF) nanosheet and its derived heterostructure composed of NiMn-MOF decorated with ultrafine Pt nanocrystals (PtNC/NiMn-MOF) are rationally designed. By leveraging the synergistic effect of Mn and Ni, along with the strong electronic interaction between NiMn-MOF and PtNC at the interface, the optimized catalysts (NiMn-MOF and PtNC/NiMn-MOF) exhibit substantially reduced potentials of 1.459 and -0.129 V to reach 1000 mA cm-2 during the UOR and HER. Theoretical calculations confirm that Mn-doping and the heterointerface between NiMn-MOF and Pt nanocrystals regulate the d-band center of the catalyst, which in turn enhances electron transfer and facilitates charge redistribution. This manipulation optimizes the adsorption/desorption energies of the reactants and intermediates in both the HER and UOR, thereby significantly reducing the energy barrier of the rate-determining step (RDS) and enhancing the electrocatalytic performance. Furthermore, the urea degradation rates of PtNC/NiMn-MOF (96.1%) and NiMn-MOF (90.3%) are significantly higher than those of Ni-MOF and the most reported advanced catalysts. This work provides valuable insights for designing catalysts applicable to urea-rich wastewater treatment and energy-saving hydrogen production.

Electrode Selection and Catalyst Evaluation in Hydrogen Production from Alkaline Water Electrolysis: A Review

Generating hydrogen, through alkaline water electrolysis shows promise as an energy source. This review delves into the significance of choosing the electrodes and evaluating catalysts to enhance the efficiency and performance of hydrogen production. It summarizes the activation energy and losses linked to reactions in alkaline electrolysis emphasizing the necessity for electrode materials and catalysts. The review also touches upon challenges such as electricity consumption and platinum group metal based electro catalysts proposing various electrode materials and catalysts with superior activity and selectivity for hydrogen production. Additionally, it discusses electrolysis cell designs that facilitate separating by-products from hydrogen gas. The study reveals that with low over potentials of 70, 318, and 361 mV at 10, 500, and 1000 mA cm−2, respectively, NiOx/NF exhibits strong alkaline hydrogen evolution activity, resulting in great performance in alkaline HER. Moreover, it outlines advancements in alkaline water electrolysis technology focusing on enhanced efficiency and reduced operating costs associated with electricity consumption. Overall this review underscores the role of selecting electrodes and evaluating catalysts in optimizing hydrogen production from alkaline water electrolysis.

Low-valence platinum single atoms in sulfur-containing covalent organic frameworks for photocatalytic hydrogen evolution

This study focuses on optimizing catalytic activity in photocatalytic hydrogen evolution reaction by precisely designing and modulating the electronic structure of metal single atoms. The catalyst, denoted as PtSA@S-TFPT, integrates low-valence platinum single atoms into sulfur-containing covalent organic frameworks. The robust asymmetric four-coordination between sulfur and platinum within the framework enables a high platinum loading of 12.1 wt%, resulting in efficient photocatalytic hydrogen production activity of 11.4 mmol g−1 h−1 and stable performance under visible light. These outcomes are attributed to a reduced hydrogen desorption barrier and enhanced photogenerated charge separation, as indicated by density functional theory calculations and dynamic carrier analysis. This work challenges traditional notions and opens an avenue for developing low-valence metal single atom-loaded covalent organic framework catalysts to advance photocatalytic hydrogen evolution.

Hydrogen Production by Photoreforming of Organic Waste Using Cd-ZnS Solid Solution Photocatalyst via MOF Precursor

Currently, global energy consumption continues to increase, but the depletion of energy resources due to the decrease in the amount of fossil fuels that can be mined and carbon dioxide emissions due to the use of fossil fuels are becoming an issue. Under these circumstances, hydrogen has been attracted a great deal of attention as a next-generation energy source for moving away from fossil fuels. Hydrogen is eco-friendly energy that does not emit carbon dioxide during combustion. However, most of the current hydrogen production methods are obtained by reforming fossil fuels, which releases carbon dioxide. Therefore, it is desirable to establish eco-friendly hydrogen production technology that does not use fossil fuels and does not emit carbon dioxide.Photocatalyst is an eco-friendly hydrogen production technology that does not emit carbon dioxide during hydrogen production. Since the Honda-Fujishima effect announced in 1972, there have been many studies on hydrogen generation by water splitting using photocatalysts. Among them, hydrogen production by photoreforming of organic waste [1] in artificial photosynthesis using photocatalysts allows the use of waste, which has been increasing in recent years, as a resource. In addition, the use of waste reduces the environmental burden caused by landfill or incineration. Furthermore, cost reduction can be achieved because sacrificial reagents used in general photocatalytic hydrogen production are not required.There have been reports of the use of sulfide photocatalysts in the hydrogen production by photoreforming of organic wastes. For example, CdS quantum dots [1] and CdS/SiC composite photocatalysts [2]. We are also aiming to improve the hydrogen production activity using sulfide photocatalysts. Among them, Cu and In-doped zinc sulfide (ZnS) photocatalysts prepared using a metal organic framework (MOF) as a precursor have been reported to have higher hydrogen production activity and higher crystallinity than those of the conventional solvothermal synthesis [3]. However, ZnS is not visible-light responsive, and thus cannot utilize most of the solar energy. Therefore, we will design a photocatalyst that has higher hydrogen production activity by combining a photocatalyst that is responsive to visible light and can form MOFs.In this study, the preparation of cadmium sulfide (CdS) and ZnS solid solution photocatalysts via cadmium (Cd) and zinc (Zn) MOF precursors is used to improve the hydrogen production activity. We designed a photocatalyst that can maintain visible light responsivity by having it create a solid solution with visible light responsive CdS as opposed to ZnS, which does not have visible light responsivity. In addition, MOF was introduced as a precursor to improve the hydrogen production activity by reducing the number of defects, which are the recombination centers of electrons and holes, by improving the crystallinity.The MOF precursor was prepared by an existing method and the solid solution photocatalyst was obtained by solvothermal synthesis by mixing it with a sulfide source. The solid solution photocatalyst was then used to measure hydrogen production under artificial sunlight. The measurement was performed using gas chromatography to check the change in hydrogen production over time. The results showed that the amount of hydrogen production was significantly higher than that of the CdS photocatalyst. The XRD measurements of the fabricated solid solution photocatalyst also showed a shift in the peaks. Furthermore, differences in the hydrogen production activity and the shift ratio of the XRD peaks were confirmed depending on the type of MOF used as a precursor.References： [1] David W. Wakerley, Moritz F. Kuehnel, et al, NATURE ENERGY, 2017, 2, 17021. [2] H. Nagakawa, M. Nagata, ACS Appl. Mater. Interfaces, 2021, 13, 47511–47519. [3] H. Nagakawa, M. Nagata, Adv. Mater. Interface, 2022, 9, 2101581. Figure 1

Electrochemical Activities of Mesoporous Pt Particles/MWCNT/ITO Electrodes for Hydrogen Generation and Glycerol Oxidation

Hydrogen produced via water electrolysis has attracted attention as a next-generation secondary energy source because of its high mass energy density and its ability to be produced by low greenhouse gas emissions during water electrolysis. In contrast to hydrogen generation at the cathode in water electrolysis, oxygen production at the anode via water electrolysis, requires a high overpotential. In this study, glycerol oxidation, which produces fine chemicals, was used to reduce the overpotential of the anode reaction. Platinum is a highly active catalyst for both hydrogen production and glycerol oxidation; however, it is not suitable for large-scale operations because of its high cost. To reduce the amount of platinum used, mesoporous platinum was electrochemically deposited on multiwalled carbon nanotube (MWCNT) film electrodes,to prepare electrodes with excellent conductivity and a large Pt surface area. The three-dimensional structure of the porous composite thin-film influences the mass transfer of products associated with hydrogen production and glycerol oxidation. Furthermore, the morphology of mesoporous Pt can nfluence electrohemical activities for these reactions by changing the surface structure of platinum. In this study, we investigated the effects of potential and the amount of electricity applied during mesoporous Pt deposition, resulting in different Pt morphologies, on the electrochemical activities for hydrogen production and glycerol oxidation at thin-film electrodes. MWCNTs were deposited on the ITO substrate via electrophoresis using sodium dodecyl benzene sulfonate (SDBS) as a surfactant. Subsequently, Pt particles were deposited on the MWCNT film electrodes via chronoamperometry in a solution containing Pt ion and Brij58. The Pt particles were deposited until the amount of electric charges reached 100 mC, 300 mC, 500 mC, and 800 mC by applying different potentials to the MWCNT film electrode, i.e., -0.1 V, -0.3 V, -0.5 V, or -0.7 V. Subsequently, micelles of Brij58 embedded in the Pt particles were removed by immersing the electrodes in ethanol to prepare mesoporous Pt/MWCNT electrodes with pore sizes in Pt particles of 5-10 nm. To evaluate the electrochemical performance of the as-prepared electrodes for hydrogen production and glycerol oxidation, cyclic voltammetry (CV) and polarization curve measurements were performed in a 0.1 M glycerol solution containing 0.1 M NaOH. All electrochemical measurements were carried out using a three-electrode cell with an as-prepared electrode as the working electrode, Ag/AgCl (saturated KCl) as the reference electrode, and platinum wire as the counter electrode.As shown in Fig. 1 and 2, one main oxidation peak was observed in cyclic voltammograms measured in the glycerol solution for all mesoporous Pt particles/MWCNT electrodes at around 0.3 V, and additional oxidation peak was observed at nobler potential than the main peak when the amount of electric charge during platinum deposition was 300 mC and more for electrodes prepared at -0.1 V. These peaks are due to the oxidation current related to glycerol, as both of them were not observed in the 0.1 M NaOH solution. By increasing the electrical charges for Pt deposition, the oxidation peak potential at around 0.3 V was observed to shift to baser potential (Fig.1), which suggest better electrochemical activity. Comparing the voltammograms of electrodes prepared at different deposition potentials, the oxidation peak potential is the smallest for the electrode prepared at -0.3 V, and the oxidation peak current at around 0.3 V appeared to be larger when applying potential of -0.5 and -0.7 V (Fig.2). These changes both in the potential and current of the peak are partially due to the effect of the additional oxidation peak observed at nobler potential than the main peak, which was observed to shift to a baser potential by changing the deposition potential from -0.1 V to -0.7 V. The exchange current density calculated from the polarization curve was 4.64 mA/㎠ for hydrogen production and 9.12 mA/㎠ for glycerol oxidation for the Pt/MWCNT electrodes prepared at -0.5V with 300mC, showing the best electrochemical activity in both reactions among all the prepared-electrodes. The influence of the thin-film morphology is also discussed in this presentation. Figure 1

Modulating the Band Structure of Two-Dimensional Black Phosphorus via Electronic Effects of Organic Functional Groups for Enhanced Hydrogen Production Activity.

Electronic effects of organic functional groups play a fundamental role in determining the rate and/or direction of organic chemical reactions. The implementation of this concept in selective organic catalysis is achieved by tuning the electronic effects of organic functional groups to alter the corresponding reactivity. However, this approach has hardly been applied to modulate the band structure of inorganic materials. Here, we show that modulating the electronic band structure of two-dimensional black phosphorus (BP) is possible via the electronic effects of organic functional groups covalently modified on its surface. Organic functional group can either donate or withdraw charge density from BP surface, which will alter the bonding/anti-binding orbitals occupancy and thus shift the band-edge positions of functionalized BP downward/upward. Therefore, the valence-band maxima and the conduction-band minima of functionalized BP can be continuously tuned by changing the binding group with different Hammett parameters. Finally, unexpectedly high hydrogen evolution reaction rates under visible light are achieved using functionalized BP heterojunctions as photocatalysts. This work underscores the significant role of electronic effects in chemically controlling BP's band structure, offering greater flexibility and affordability beyond physical method limits.

Modulating the band structure of two‐dimensional black phosphorus via electronic effects of organic functional groups for enhanced hydrogen production activity

Electronic effects of organic functional groups play a fundamental role in determining the rate and/or direction of organic chemical reactions. The implementation of this concept in selective organic catalysis is achieved by tuning the electronic effects of organic functional groups to alter the corresponding reactivity. However, this approach has hardly been applied to modulate the band structure of inorganic materials. Here, we show that modulating the electronic band structure of two‐dimensional black phosphorus (BP) is possible via the electronic effects of organic functional groups covalently modified on its surface. Organic functional group can either donate or withdraw charge density from BP surface, which will alter the bonding/anti‐binding orbitals occupancy and thus shift the band‐edge positions of functionalized BP downward/upward. Therefore, the valence‐band maxima and the conduction‐band minima of functionalized BP can be continuously tuned by changing the binding group with different Hammett parameters. Finally, unexpectedly high hydrogen evolution reaction rates under visible light are achieved using functionalized BP heterojunctions as photocatalysts. This work underscores the significant role of electronic effects in chemically controlling BP’s band structure, offering greater flexibility and affordability beyond physical method limits.

Unveiling the potential of Au cocatalysts to induce SPR charges on CuO/CdS system for sunlight driven hydrogen production†

Atmospheric pollution and increasing costs of the fossil fuels have compelled researchers to explore the alternative sources. Objective of current project is to discover catalysts that can drive water splitting reaction with sunlight. To the purpose, visible light active catalysts i.e., CdS, CuO/CdS, and Au@CuO/CdS have been synthesized and evaluated for hydrogen generation activities. Gold cocatalysts have been employed to enhance the surface stability and catalytic efficiencies. Whereas, CuO/CdS heterojunction have been synthesized to improve charge separation ability. The optical characteristics, structural properties, and morphology of catalysts have been evaluated by UV–Vis/DRS, XRD, Raman, BET, SEM, AFM, PL and FTIR techniques. Chemical compositions, photocurrent or charge transfer have been verified with XPS, EDX and EIS results. Catalytic reactions were performed in photoreactor (150 mL/Pyrex), whereas hydrogen production activities were predicted via online GC-TCD (Shimadzu-2010/Japan). Results depict that catalyst with 0.8 % of Au on CuO/CdS exhibit relatively higher activity (i.e., 32.13 mmol g−1 h−1) than the other catalysts of the series. Higher activities were attributed to the presence of Au cocatalysts. It has been predicted that existence of gold develops Schottky junctions that progressively rectify the surface charges (i.e., movement of electrons). Additionally, gold induces the SPR charges and enhances activity of electrons. Schottky junctions formed by Au cocatalysts on CuO/CdS system restrict the charge recombination i.e., back reactions. In this study, various factors like temperature, pH, light intensity and dose of catalysts have been assessed and discussed. On the basis of activities, it has been concluded that work reported herein hold promise to replace the conventional catalysts used for hydrogen energy technologies.

From waste to resource: Hydrogen generation and antimicrobial activity of Ag-based photocatalysts recovered from biomedical waste

Electrocardiogram (ECG) disposable electrodes contain a substantial amount of silver (Ag), which can be extracted and recycled. Most current methods for recovering Ag from waste are expensive and environmentally harmful. This study investigated a sustainable chemical process for extracting Ag from discarded medical electrodes using a simple Cu(II) solution under moderately acidic conditions. Using response surface methodology (RSM) based on a three-level, full-factorial design, the optimized extraction conditions were determined as pH = 4.78, T = 80°C, [Cu(II)]₀ = 8.0 × 10⁻³ M, and [NaCl]₀ = 3.72 M. Under these conditions, a process efficiency approaching 100 % was achieved. Moreover, the recovery of metallic silver exceeded 85 %, even when using real matrices. (i.e., discarded ECG electrodes). As a result, the Ag-containing leachate solutions were utilized to synthesize silver-based materials with varying Ag content. These materials demonstrated (i) excellent photocatalytic activity for hydrogen production in aqueous solutions containing organic compounds and (ii) significant antipathogenic properties. In summary, effective Ag/TiO₂ photocatalytic materials with high efficiency for hydrogen production and antimicrobial activity were successfully prepared through a novel, sustainable, and cost-effective chemical recovery process of silver from discarded ECG electrodes.

A novel highly efficient co-catalyst for enhancement of photocatalytic hydrogen production activity and stability of Cd0.5Zn0.5S: Silicotungstic acid nanoparticles embedded with NiOx clusters

Development of an efficient and stable photocatalyst is crucial for the practical implementation of photocatalytic hydrogen production technology on a large scale. Consequently, the exploration of efficient co-catalysts has consistently been a focal point in the field of photocatalytic hydrogen production. Here, a highly efficient co-catalyst was developed using NiOx clusters and silicotungstic acid nanoparticles to enhance the photocatalytic activity and stability of Cd0.5Zn0.5S nanoplates for H2 evolution. Subsequently, the photocatalytic behavior and mechanism of the as-prepared Cd0.5Zn0.5S-based photocatalyst were investigated. The results demonstrate that the as-prepared Cd0.5Zn0.5S-based photocatalyst exhibits high photocatalytic activity for H2 generation, achieving a top H2 evolution rate of 1.51 mmol g−1 h−1. Moreover, the silicotungstic acid nanoparticles embedded with NiOx clusters are an excellent co-catalyst for Cd0.5Zn0.5S. Under bright irradiation (142.4 mW cm−2), the photocatalytic activity of Cd0.5Zn0.5S nanoplates is boosted by 11.8-fold, while this enhancement increases up to 104-fold under mild light irradiation (71.8 mW cm−2). Furthermore, the stability of Cd0.5Zn0.5S nanoplates is significantly improved with this co-catalyst, retaining 96.7 % of its initial photocatalytic activity after five cycles of use. These findings will serve as a valuable reference for the design and preparation of efficient Cd0.5Zn0.5S-based photocatalysts in future.

P3HT/g-C3N4 composite fiber membranes for high-performance photocatalytic hydrogen evolution

As a superstar semiconducting polymer, poly(3-hexylthiophene) (P3HT) demonstrates high efficiency in carrier transport ability and wide absorption range. However, pristine P3HT exhibits minimal photocatalytic activity as a result of its short carrier transport distance and fast electron-hole recombination. Here, we strategically fabricated P3HT/g-C3N4 composites on polymethyl methacrylate (PMMA) fiber (PTCN) via electrospinning and the physicochemical properties were fully investigated. Raman spectroscopy, ultraviolet–visible (UV–Vis) absorption spectra and X-ray photoelectron spectroscopy (XPS) results demonstrated a well-defined p-n heterojunctions can be formed between P3HT and g-C3N4 molecules through π-π interaction and extended conjugated length of P3HT could be achieved by tuning the ratios of P3HT relative to g-C3N4. The presence of the heterojunctions facilitates the effective disconnection of the electron-hole pairs, resulting in a significantly enhanced photocatalytic hydrogen evolution rate of 7327 μ mol/(h·g) for the PTCN fiber membranes. This value exceeds that of P3HT fibers by 57.7 times and powder g-C3N4 by 6.8 times, respectively. The high photocatalytic hydrogen production activity of P3HT/g-C3N4 fiber membrane expands the application of P3HT. More importantly, these results indicate that the construction of heterojunction fiber materials is a promising approach for improving the photocatalytic ability of conjugated semiconducting polymers.

Correlation between the Molecular Properties of Semiconducting Polymers of Intrinsic Microporosity and Their Photocatalytic Hydrogen Production.

Increasing the interface area between organic semiconductor photocatalysts and electrolyte by fabricating nanoparticles has proven to be an effective strategy to increase photocatalytic hydrogen production activity. However, it remains unclear if increasing the internal interface by the introduction of porosity has as clear benefits for activity. To better inform future photocatalyst design, a series of polymers of intrinsic microporosity (PIMs) with the same conjugated backbone were synthesized as a platform to independently modulate the variables of porosity and relative hydrophilicity through the use of hydrophilic alcohol moieties protected by silyl ether protecting groups. When tested in the presence of ascorbic acid and photodeposited Pt, a strong correlation between the wettable porosity and photocatalytic activity was found, with the more wettable analogue of two polymers of almost the same surface area delivering 7.3 times greater activity, while controlling for other variables. Transient absorption spectroscopic (TAS) investigation showed efficient intrinsic charge generation within 10 ps in two of the porous polymers, even without the presence of ascorbic acid or Pt. Detectable hole polarons were found to be immediately extracted by added ascorbic acid, suggesting the generation of reactive charges at regions readily accessible to electrolyte in the porous structures. This study directs organic semiconductor photocatalysts design toward more hydrophilic functionality for addressing exciton and charge recombination bottlenecks and clearly demonstrates the advantages of wettable porosity as a design principle.

Bicontinuous nickel/tin oxide films with enhanced photoelectrochemical hydrogen production efficiency

Self-assembled bicontinuous NiO:SnO2 films are proposed for enhanced photoelectrochemical hydrogen production efficiency due to their high interface-to-volume ratio and three-dimensional interconnectivity. The X-ray diffraction confirms the superior crystallinity of the bicontinuous NiO:SnO2 films. Bicontinuous NiO:SnO2 films reveal a heterostructure of mixed NiO and SnO2 phases, where the NiO phase exhibits the distribution of small grains, whereas the SnO2 phase exhibits large agglomerates of SnO2 crystals embedded in the NiO structure. The bicontinuous NiO:SnO2 films exhibit lower bandgap energy and higher electrical conductivity compared to pure NiO and pure SnO2 films. The photoresponsivity of the bicontinuous oxide films is higher than pure NiO and pure SnO2 films. These results imply the presence of strong charge interactions at the three-dimensional interfaces in bicontinuous NiO:SnO2 films. The hydrogen revolution reaction analysis confirms that the bicontinuous NiO:SnO2 films exhibit higher photoelectrocatalyst hydrogen production activity compared to pure NiO and pure SnO2 films.

High-entropy alloy-enhanced ZnCdS nanostructure photocatalysts for hydrogen production

High-entropy alloys (HEA) have been shown to be potential cocatalysts for photocatalysis, but the design of ideal semiconductor/HEA composite photocatalysts is challenging due to the complexity of their composition and the interactions within multi-element systems. To address this issue, PtCuFeNiCo HEA was selected as a cocatalyst, and a ZnCdS/PtCuFeNiCo (abbreviated as ZnCdS/HEA) nanostructured photocatalyst was designed for hydrogen production from water splitting. ZnCdS/HEA was prepared using a simple liquid-phase precipitation method, a template-assisted cation exchange method, and an ultrasound-assisted recombination method. Photocatalytic experiments showed that the hydrogen production activity of ZnCdS/HEA under visible light was 5.99 mmol·g−1·h−1, which is 11.7 times that of ZnCdS and significantly higher than that of ZnCdS/Pt. Experiments and density functional theory calculations indicated that ZnCdS/HEA formed a Schottky heterojunction. The performance enhancement was attributed to the synergistic effect between PtCuFeNiCo HEA and ZnCdS, which enhanced light absorption, improved the separation and transfer of photogenerated electrons and holes, as well as provided abundant catalytic active sites and increased surface reaction activity. This study highlights the potential of HEAs and provides theoretical and experimental references for the rational design of efficient semiconductor/HEA composite materials.

Study of Complexation Patterns in the System Ni2+, MoO42–, P2O74–, Cit3–for the Development of Poly-Ligand Electrolytes (Study of complexation patterns)

The complexation behavior in systems containing Ni2+, MoO42−, P2O74−, Cit3− - ions have been thoroughly investigated. The study determined the composition and instability constants of both mono- and biligand complex compounds at a constant ionic strength of the solution (Ic=1). By analyzing the concentration ratios of the complexing agent and ligands, the composition of mono- and polyligand complexes was elucidated. The complexation study utilized the potentiometric method, which is based on the functional dependence of the potential of the indicator electrode on the concentration of the complexing agent ions. The results enabled the calculation of the ionic composition of aqueous solutions of nickel complexes with citrate and diphosphate ions, depending on their concentrations. A proposed scheme for the formation of heteronuclear nickel-molybdenum complexes takes into account the sequence of component introduction into the electrolyte to form complexes of a specific composition. These findings were applied to develop electrolyte compositions for coating with alloys based on iron subgroup metals with molybdenum. These alloys exhibit several valuable properties, including corrosion resistance, electrocatalytic activity in hydrogen production, and enhanced operational characteristics.

1-Dimensional metal Nitride-Supported platinum nanoclusters for Low-Temperature hydrogen production from formic acid

Formic acid is widely recognized as a suitable liquid hydrogen carrier for linking renewable energies toward various economic sectors. Designing efficient and stable heterogeneous catalysts for low-temperature hydrogen generation from formic acid is vital for this topic. In this study, a rational hierarchical architecture is explored by assembling Pt nanoclusters with 1-dimensional (1D) GaN nanowires. The catalytic architecture describes a considerable hydrogen production activity of 54.89 mmol·gcat−1·h−1 with a nearly 100 % selectivity and a turnover frequency (TOFPt) of 505.7 h−1 under near ambient conditions, enabling the achievement of a high turnover number of 306,981 mol H2 per mole Pt over 200 h of long-term operation. Through comprehensive mechanistic studies, it is unraveled that the synergistic effect between Pt nanoclusters and GaN significantly reduces the energy barrier for the formation of the key HCOO* intermediate from formic acid dehydrogenation whereas significantly increases the energy barrier of HCOOH → HCO* + *OH. It thus simultaneously contributes to improving the activity and selectivity of formic acid decomposition toward H2. This study proposes a promising strategy for hydrogen generation from formic acid at low temperatures, which is critical for achieving carbon neutrality by coordinating industrial waste heat with renewable energies via liquid hydrogen carriers.

Spirobifluorene-Based D-A Type Conjugated Polymer Photocatalysts for Water Splitting

Exploring synthetic pathways for efficient photocatalysts has always been a major goal in catalysis. The performance of organic photocatalysts is affected by a variety of complex factors, and how to understand the structure–effect relationship is the key to designing efficient photocatalysts. This work explored the feasibility of constructing large-specific-surface-area conjugated microporous polymers (CMPs) based on stereoscopic units like spirobifluorene and achieving efficient photocatalytic activity by modulating the donor–acceptor (D-A) ratio with dibenzothiophene sulfone. Crosslinked pore structures were successfully constructed, and the specific surface area increased with the ratio of spirobifluorene. When the molar ratio of D-A was 1:20, polymer Spso-3 showed the highest photocatalytic hydrogen production activity, at 22.4 mmol h–1 g–1. The findings indicate that constructing D-A type CMPs should be a promising approach to improving the performance of photocatalytic water separation. The appropriate push–pull effect of the D-A structure promotes the photo-induced separation of electron–hole pairs, and the porous structure built on steric units offers ample space for catalytic reactions. This work could provide case references for structural design and the structure–effect relationship of efficient polymer photocatalysts.

Single-Atom Electron Pumps Over Transition Metal Chalcogenides Boosting Photocatalysis.

Cocatalyst is of paramount significance to provide fruitful active sites for suppressing the spatial charge recombination toward boosted photocatalysis. Up to date, exploration of robust and stable cocatalysts is remained challenging. Inspired by the intrinsic merits of single-atom catalysts (SACs), such as distinctive electronic structure and high atomic utilization efficiency, single-atom/transition metal chalcogenides (TMCs) is utilized as a model to synthesize CdS-Pd single-atom catalyst (CdS-PdSA) heterostructures. This demonstrates the precise anchoring of isolated metal single-atom catalysts (SACs) onto TMCs through a simple yet effective wet-chemical strategy. The resulting heterostructures exhibit significantly enhanced and stable photocatalytic activity for selective anaerobic organic transformations and hydrogen production under visible light. This enhancement is primarily inferred due to the role of Pd SACs as electron pumps, which directionally trap the electrons photoexcited over CdS, accelerating the spatial charge separation and prolonging the carrier lifespan. The charge transport route and photocatalytic mechanism are elucidated. This work underscores the potential of SACs as cocatalysts in heterogeneous photocatalysis, offering valuable insights for the rational design of atomic-level cocatalysts for solar-to-chemical energy conversion and beyond.