Mechanism Of Water Splitting Research Articles

Theoretical insight into water splitting mechanism of B doped tri-s-triazine-based g-C3N4/m-BiVO4(001) heterojunction photocatalyst

We evaluated the geometrical, electrical, optical properties and charge transfer of pristine g-C3N4 (tri-s-triazine-based graphitic phase carbon nitride) B-doped g-C3N4 (doping of boron atoms into graphitic phase carbon nitride), m-BiVO4(001) surface (monoclinic bismuth vanadate (001) surface), g-C3N4/m-BiVO4(001) heterojunction and B-doped g-C3N4/m-BiVO4(001) heterojunction using density functional theory (DFT) simulations. Based on the findings, the synergistic impact of doping and heterojunctions on g-C3N4’s electronic properties as well as the photocatalytic mechanism of heterojunctions were analyzed. The doping of B atoms gives g-C3N4 a unique structure and reduces the effective mass of carriers, proving to be an effective way to increase electron transport capacity. The interfacial adhesion energy, binding energy, and interfacial distance all point to a van der Waals (vdW) interaction between g-C3N4 and m-BiVO4(001) surface. The findings demonstrate that the g-C3N4/m-BiVO4(001) heterojunction, in comparison to pristine g-C3N4 and m-BiVO4(001) surface, has a narrow bandgap, absorbs more photons and has a build-in electric field, all of which are advantageous for visible light-driven activity, the separation and transfer of charge carriers, and maintaining a strong redox ability. Additionally, the B-doped g-C3N4/m-BiVO4(001) heterojunction outperformed the g-C3N4/m-BiVO4(001) heterojunction in terms of visible light absorption efficiency, hydrogen production capacity, and interfacial charge density. The Z-scheme mechanism over the heterojunction has been proposed based on semiconductor theory to disclose the separation and transfer pathway of photogenerated charge during the photocatalytic water splitting process. The theoretical design provided here provides a theoretical reference for the efficient of g-C3N4-based photocatalysts for the efficient use of solar energy and the protection of the environment.

Hydrogen production on nano Al2O3 surface by water splitting using gamma radiation

AbstractOBJECTIVESDue to changes in climate and the estimation of fossil fuel exploitation in the future, there is a great demand for green energy. Therefore, hydrogen production was studied by water splitting using Al2O3 nanoparticles as a radiation catalyst with gamma rays irradiationEXPERIMENTALThe effects of different particle sizes, surface area, amounts of radiation catalyst and the time of gamma rays irradiation were studied. The kinetics of hydrogen generated by the water decomposition of the water system with Al2O3 nanoparticles were also studied. It was determined that the hydrogen produced by water splitting with smaller‐sized nanoparticles was 1.4–1.6 times greater than the large‐sized catalysts.RESULTS AND DISCUSSIONThe best conditions were 5 nm particle size, 250 mm2/g surface area, 0.25 g amount and 10 h time (5.97 molecules/100 eV). The equivalent dispersal of radiation nanocatalyst (alumina) in water and greatly more sorption of water on the catalyst surface caused more effective radiolysis. The mechanism of water splitting and radiolysis was also established.CONCLUSIONThe reported method may be used in the future for hydrogen production on an industrial scale. © 2023 Society of Chemical Industry (SCI).

Unravelling the interfacial water structure at the photocatalyst strontium titanate by sum frequency generation spectroscopy.

The direct conversion of solar energy to hydrogen is considered as a possible method to produce carbon neutral hydrogen fuel. The mechanism of photocatalytic water splitting involves the chemical breakdown of water and re-assembly into hydrogen and oxygen at the interface of a photocatalyst. The selection rules of a suitable material are well established, but the fundamental understanding of the mechanisms, occurring at the interface between the catalyst and the water, remains missing. Using surface specific sum frequency generation spectroscopy, we present here characterisation of the interface between water and the photocatalyst strontium titanate (SrTiO3). We monitor the OH-stretching vibrations present at the interface. Their variations of intensities and frequencies as functions of isotopic dilution, pH and salt concentration provide information about the nature of the hydrogen bonding environment. We observe the presence of water molecules that flip their orientation at pH 5 indicating the point of zero charge of the SrTiO3 layer. These water molecules are oriented with their hydrogen away from the surface when the pH of the solutions is below 5 and pointing towards the surface when the pH is higher than 5. Besides, water molecules donating a H-bond to probably surface TiOH groups are observed at all pH.

Tuning the water-splitting mechanism on titanium dioxide surfaces through hydroxylation.

Experimental research demonstrates that surface hydroxyl groups can boost TiO2's ability to split water but the water splitting mechanism and roles of hydroxyl groups are still not clear. The hydroxyl groups formed by H2O or H2 cracking on pure TiO2 surfaces are represented by types I (OH1) and II (OH2), respectively. Six types of hydroxylated TiO2 surfaces of anatase (101), rutile (110), and brookite (210) with OH1 and OH2 hydroxyl groups were constructed. The mechanism of the water oxidation process on the hydroxylated TiO2 surfaces was systematically investigated through density functional theory calculations. The variation and significant roles of hydroxyl groups in the mechanism of the oxygen evolution reaction (OER) and product selectivity were discussed. All hydroxylated TiO2 surfaces eventually tend to produce oxygen through a four-electron/proton process, which is fundamentally different from the OER process on pure Ti2O surfaces from a thermodynamic standpoint. The lowest surface overpotential of R-110-OH1 is 0.53 V, the highest surface overpotential of B-210-OH2 is 1.49 V, and the surface overpotentials of other hydroxylated TiO2 are between 0.5 and 1.5 V. Rutile (110) and brookite (210) have hydroxyl groups of the OH1-type that are more conducive to the OER process. This study investigates the mechanism of water splitting on the surface of hydroxylated TiO2, allowing for a deeper understanding of the function of surface hydroxyl groups in the OER process as well as providing instructions for future research into the development of effective water-splitting catalysts based on hydroxylated TiO2 surfaces.

An Insight into Carbon Nanomaterial-Based Photocatalytic Water Splitting for Green Hydrogen Production

At present, the energy shortage and environmental pollution are the burning global issues. For centuries, fossil fuels have been used to meet worldwide energy demand. However, thousands of tons of greenhouse gases are released into the atmosphere when fossil fuels are burned, contributing to global warming. Therefore, green energy must replace fossil fuels, and hydrogen is a prime choice. Photocatalytic water splitting (PWS) under solar irradiation could address energy and environmental problems. In the past decade, solar photocatalysts have been used to manufacture sustainable fuels. Scientists are working to synthesize a reliable, affordable, and light-efficient photocatalyst. Developing efficient photocatalysts for water redox reactions in suspension is a key to solar energy conversion. Semiconductor nanoparticles can be used as photocatalysts to accelerate redox reactions to generate chemical fuel or electricity. Carbon materials are substantial photocatalysts for total WS under solar irradiation due to their high activity, high stability, low cost, easy production, and structural diversity. Carbon-based materials such as graphene, graphene oxide, graphitic carbon nitride, fullerenes, carbon nanotubes, and carbon quantum dots can be used as semiconductors, photosensitizers, cocatalysts, and support materials. This review comprehensively explains how carbon-based composite materials function as photocatalytic semiconductors for hydrogen production, the water-splitting mechanism, and the chemistry of redox reactions. Also, how heteroatom doping, defects and surface functionalities, etc., can influence the efficiency of carbon photocatalysts in H2 production. The challenges faced in the PWS process and future prospects are briefly discussed.

Enhanced Electron-Hole Separation in Phosphorus-Coordinated Co Atom on g-C3N4 toward Photocatalytic Overall Water Splitting.

Revealing the decoration mode of g-C3N4 and understanding the physical mechanism of overall water splitting is important for the further improvement of the photocatalytic activity of g-C3N4-based materials. With core level shift and molecular dynamics simulations based on first-principles calculations, Co1(PHx)3 anchored on the triazine of g-C3N4 is determined as a stable single-atom catalyst with high efficiency for photocatalytic overall water splitting. The separated spin-polarized charge density distribution of valence-band maximum and conduction-band minimum states is beneficial for the long lifetime of photoexcited electrons and holes. An anchored Co single atom site is the active site for oxygen evolution reaction, and nitrogen atoms act as active sites for hydrogen evolution reaction. This new decoration mode of g-C3N4 opens a possible way to functionalize g-C3N4 on both triazine and void sites to realize the separation of OER and hydrogenation reaction by water splitting.

Water Splitting: Recent Scientific and Technological Advances

Hydrogen is a green fuel and has great potential as a sustainable and renewable energy carrier. It can be produced by electrocatalytic, photocatalytic, photoelectrochemical water splitting. It is essential to develop highly effective catalysts for economic and large-scale hydrogen production. Currently, phosphorus-containing catalysts have gained a lot of attention because of their unique properties such as different oxidation states, tunable structure, and exceptional physiochemical properties. In this review paper, the topics discussed are part of numerous research carried out to date in water splitting by phosphorus-containing photocatalysts and electrocatalysts that include phosphorus in elemental form, metal phosphonates, metal phosphates, transition metal phosphides, metal phosphorus trichalcogenides, and phosphorus-doped materials. A detailed mechanism of water splitting and the activity origin of phosphorus-containing catalysts are presented. Lastly, there are some challenges in water splitting listed below that we need to overcome shortly.

Molten salt-assisted synthesis of nitrogen-vacancy crystalline graphitic carbon nitride with tunable band structures for efficient photocatalytic overall water splitting

The photocatalytic overall water splitting performance of graphitic carbon nitride (g-C3N4) has still been restricted by its inefficient charge separation efficiency. Herein, nitrogen-vacancy crystalline g-C3N4 nanosheets (g-C3N4-D) with tunable band structures were successfully prepared by the alkali-molten salt-assisted method for efficient photocatalytic overall water splitting. Among them, g-C3N4-D2 not only combines the advantages of the amorphous and crystalline state of two-dimensional g-C3N4 nanosheets, but also introduces nitrogen vacancy to adjust the bandgap structures of crystalline g-C3N4 by an alkali etching, thus improving the light energy utilization and charge separation efficiency. TEM and EPR spectrum prove the existence of N defects in the crystalline g-C3N4. The excellent and stable photocatalytic overall water splitting activity with H2 and O2 evolution rate of 49.60 μmol g−1 h−1 and 24.71 μmol g−1 h−1 was obtained over g-C3N4-D2 with Pt and Co3O4 nanorods as cocatalysts (Pt/g-C3N4-D2/3%Co3O4 NRs) under AM 1.5G simulated light irradiation. In the half-reaction experiments, the maximum H2 evolution rate of Pt/g-C3N4-D2/3%Co3O4 NRs is 3.78 mmol g−1 h−1 with a significant quantum efficiency of 11.94 % at 400 nm, and the solar-hydrogen conversion efficiency (STH) is 1.48 %. The photocatalytic water oxidation activity of Pt/g-C3N4-D2/5%Co3O4 NRs is 42.34 μmol g−1 h−1. Additionally, the potential mechanism of photocatalytic overall water splitting was testified by in-situ XPS. This work provides a simple strategy for further advancing the potential application of g-C3N4 by molten salt-assisted alkali etching to introduce N vacancies to regulate the band gap of crystalline g-C3N4 for photocatalytic overall water splitting.

Advanced Two-Dimensional Materials for Green Hydrogen Generation: Strategies toward Corrosion Resistance Seawater Electrolysis─Review and Future Perspectives

Excessive usage of nonrenewable resources to meet global energy requirements has become a serious concern from the energy and environmental perspective. The continuous emission of CO2 in the environment from fossil fuels has become a major cause of global warming. Green hydrogen generation through seawater electrolysis has been an emergent technology that can play a prominent role in replacing conventional energy sources. Electrolysis of seawater using renewable sources such as solar, wind, and geothermal generates green hydrogen which has almost negligible harmful byproducts. Different ions present in seawater such as chlorides and sulfates impose serious corrosion problems during the electrolysis process as chloride ions penetrate the metal electrode surface and oxidize it and also liberate chlorine gas at the anode. For the electrolysis processes, catalysis plays a challenging task to reduce the kinetic barrier for the conversion of water molecules to hydrogen and oxygen products. Photoelectrocatalysts are another kind of semiconductor-based catalyst in which band gap, exchange charge carrier, and surface area play key roles in the water-splitting process. Two-dimensional nanomaterials offer many advantages like high specific surface area for electron transfer, high tunable functionalities, and flexible structural properties that make them suitable for different applications. Layered double hydroxide (LDH) as a highly efficient catalyst has the potential to perform the hydrogen production process as per the industrial application. LDH has many advantages in an effective water-splitting mechanism that includes easy synthesis methods, flexible morphology, long-term stability, and adaptability to different applications. Another major advantage is the corrosion inhibition property of LDH by different mechanisms like adsorption of corrosion-responsible ions, self-healing technique, and protective film formation which are discussed briefly in this review. This review provides a state-of-the-art analysis about the various important strategies to be adopted for effective seawater electrolysis. Finally, we examine the new challenges and the novel approaches to suppress corrosion processes during seawater electrolysis.

TiO2 nanoparticles modified with ZnIn2S4 nanosheets and Co-Pi groups: Type II heterojunction and cocatalysts coexisted photoanode for efficient photoelectrochemical water splitting

The optimization of photoelectrode is the key issue for the efficient photoelectrochemical water splitting process. In this work, the TiO2 photoanode is synthesized and modified with ZnIn2S4 nanosheets and Co-Pi cocatalyst (TiO2/ZnIn2S4/Co-Pi) for a favorable photoelectrochemical performance. The synthesis and modification process of the TiO2 photoanode are optimized. The physical and chemical characterizations indicate that the TiO2 has a nano-cauliflower-like structure and rutile crystal form modified with a network hexagonal ZnIn2S4 nanosheets and amorphous Co-Pi groups. After optimization of the hydrothermal and annealing process, the optimized TiO2 photoanode manifests a photocurrent density of 1.82 mA cm−2, 1.73-fold of the pristine TiO2 photoanode (1.05 mA cm−2). With the surficial ZnIn2S4 and Co-Pi modification, the photocurrent density of the TiO2/ZnIn2S4/Co-Pi photoanode is raised to 5.05 mA cm−2, 5.32-fold of the optimized TiO2 photoanode (1.82 mA cm−2). The applied bias photon-to-current efficiency, the charge separation and injection efficiencies of the TiO2/ZnIn2S4/Co-Pi photoanodes are 8.79, 3.40, and 1.64-folds of the optimized TiO2 photoanode. Combined the Tauc plot, valence band XPS spectra, EIS and Mott-Schottky analysis, the PEC water splitting mechanism could be that: (i) the type II heterojunction formed by the TiO2 and ZnIn2S4 semiconductors improves the charge separation/injection efficiencies; (ii) the Co-Pi groups facilitate the oxygen evolution kinetics; (iii) the Co-Pi groups and 2D ZnIn2S4 nanosheets synergistically enhance the charge separation efficiency. This investigation could offer a prospect of practical implementation for photoelectrochemical water splitting.

Urea-oxidation-assisted electrochemical water splitting for hydrogen production on a bifunctional heterostructure transition metal phosphides combining metal–organic frameworks

Electrocatalyzed urea-assisted wastewater splitting is a promising approach for sustainable hydrogen production. However, the lack of cost-efficient electrocatalysts hinders its practical application. Herein, bimetal phosphide (NiCoPx) nanowire arrays decorated with ultrathin NiFeCo metal–organic framework (NiFeCo-MOF) nanosheets on porous nickel foam (NF) were designed for urea-assisted wastewater splitting. The core–shell NiCoPx@NiFeCo-MOF hybrids were prepared via successive hydrothermal, gas-phase phosphorization and hydrothermal strategies. Encouragingly, the novel NiCoPx@NiFeCo-MOF/NF electrode served as an excellent bifunctional electrocatalyst for both the cathodic hydrogen evolution reaction (HER) and the anodic urea oxidation reaction (UOR) in urea-assisted water splitting, which merely required an overpotential of 44 mV to deliver a current density of 10 mA cm−2 for HER and a voltage of 1.37 V to deliver a current density of 100 mA cm−2 for UOR in 1.0 M KOH + 0.5 M urea. Benefiting from the highly exposed electroactive sites in exquisite three-dimensional (3D) hierarchical structure, multicomponent synergistic effect, accelerated electron transfer, easy electrolyte access and diffusion of released gas bubbles, the as-fabricated NiCoPx@NiFeCo-MOF/NF exhibited outstanding electrocatalytic performance. The mechanism of water splitting was elucidated by density functional theory calculations. Interestingly, NiFeCo-MOF possessed optimized COO* adsorption ability on Ni sites that were beneficial to UOR intermediates. More significantly, this work paves the way for the design and fabrication of bifunctional electrocatalysts for urea-containing wastewater treatment and sustainable hydrogen production.

Predicting the oxidation states of Mn ions in the oxygen-evolving complex of photosystem II using supervised and unsupervised machine learning

Serial Femtosecond Crystallography at the X-ray Free Electron Laser (XFEL) sources enabled the imaging of the catalytic intermediates of the oxygen evolution reaction of Photosystem II (PSII). However, due to the incoherent transition of the S-states, the resolved structures are a convolution from different catalytic states. Here, we train Decision Tree Classifier and K-means clustering models on Mn compounds obtained from the Cambridge Crystallographic Database to predict the S-state of the X-ray, XFEL, and CryoEM structures by predicting the Mn’s oxidation states in the oxygen-evolving complex. The model agrees mostly with the XFEL structures in the dark S1 state. However, significant discrepancies are observed for the excited XFEL states (S2, S3, and S0) and the dark states of the X-ray and CryoEM structures. Furthermore, there is a mismatch between the predicted S-states within the two monomers of the same dimer, mainly in the excited states. We validated our model against other metalloenzymes, the valence bond model and the Mn spin densities calculated using density functional theory for two of the mismatched predictions of PSII. The model suggests designing a more optimized sample delivery and illumiation systems are crucial to precisely resolve the geometry of the advanced S-states to overcome the noncoherent S-state transition. In addition, significant radiation damage is observed in X-ray and CryoEM structures, particularly at the dangler Mn center (Mn4). Our model represents a valuable tool for investigating the electronic structure of the catalytic metal cluster of PSII to understand the water splitting mechanism.

The investigation of the electronic, optical, and thermoelectric properties of the Ge‐based halide perovskite AGeI 2 Br (a = K, Rb, Cs) compound for a photovoltaic application: First principles calculations

The electronic, optical, photocatalytic, and thermoelectric properties of inorganic halide cubic perovskite AGeI2Br (A = K, Rb, Cs) are investigated using the density functional theory, in order to use these compounds in different fields. The aim of our investigation is to bring a prediction of the free lead halide mixed compound which is still not synthesized until now, and show the potential use of these materials in the solar field. The results show that the studied compounds exhibit remarkable properties like their high absorption coefficient (over 105 cm−1) in the visible range, but the only inconvenience of these materials is that they have slightly low bandgap energy. For this purpose, the tensile effect is investigated to recognize its effect on the bandgap values and how it can be helpful to be more useful for photovoltaic application. Besides, the mechanism of photocatalytic water-splitting was studied based on the calculated bandgap energy, relative ratios of effective mass, and the valence band and the conduction band edge potential.

A review of Ni based powder catalyst for urea oxidation in assisting water splitting reaction

Water splitting has been regarded as a sustainable and environmentally-friendly technique to realize green hydrogen generation, while more energy is consumed due to the high overpotentials required for the anode oxygen evolution reaction. Urea electrooxidation, an ideal substitute, is thus received increasing attention in assisting water-splitting reactions. Note that highly efficient catalysts are still required to drive urea oxidation, and the facile generation of high valence state species is significant in the reaction based on the electrochemical-chemical mechanisms. The high cost and rareness make the noble metal catalysts impossible for further consideration in large-scale application. Ni-based catalysts are very promising due to their cheap price, facile structure tuning, good compatibility, and easy active phase formation. In the light of the significant advances made recently, herein, we reviewed the recent advances of Ni-based powder catalysts for urea oxidation in assisting water-splitting reaction. The fundamental of urea oxidation is firstly presented to clarify the mechanism of urea-assisted water splitting, and then the prevailing evaluation indicators are briefly expressed based on the electrochemical measurements. The catalyst design principle including synergistic effect, electronic effect, defect construction and surface reconstruction as well as the main fabrication approaches are presented and the advances of various Ni-based powder catalysts for urea assisted water splitting are summarized and discussed. The problems and challenges are also concluded for the Ni-based powder catalysts fabrication, the performance evaluation, and their application. Considering the key influencing factors for catalytic process and their application, attention should be given to structure−property relationship deciphering, novel Ni-based powder catalysts development and their construction in the real device; specifically, the effort should be directed to the Ni-based powder catalyst with multi-functions to simultaneously promote the fundamental steps and high anti-corrosion ability by revealing the local structure reconstruction as well as the integration in the practical application. We believe the current summarization will be instructive and helpful for the Ni-based powder catalysts development and understanding their catalytic action for urea-assisted hydrogen generation via water splitting technique. Advances and challenges of Ni based powder catalyst were reviewed for urea oxidation in assisting water-splitting reaction.

Mechanism of photocatalytic water splitting of 2D WSeTe/XS2 (X = Hf, Sn, Zr) van der Waals heterojunctions under the interaction of vertical intrinsic electric and built-in electric field

Finding photocatalytic materials with high hydrogen production efficiency is an effective way to solve the problem of the energy crisis. We use density functional theory (DFT) to predict the 2D WSeTe/XS2 (X = Hf, Sn, Zr) van der Waals (vdW) heterojunctions as the potential direct Z-scheme heterojunction photocatalysts and discuss the mechanism of photocatalytic water splitting under the interaction of vertical intrinsic electric field and built-in electric field. The WSeTe/XS2 heterojunctions have large band-edge staggered alignment, small interlayer bandgap, and good interlayer carrier recombination, which predict the direct Z-scheme charge transfer path formation. Meanwhile, the small bandgap of the 2D WSeTe/XS2 direct Z-scheme heterojunctions enables it to obtain a wide light absorption range. The built-in electric field from WSeTe to XS2 changes the charge transfer mode of the heterojunction and improves the separation efficiency of photo-generated carriers, and the vertical intrinsic electric field not only improves the hydrogen evolution reaction (HER) ability but also reduces the bandgap limitation of photocatalytic materials. In this paper, the 2D WSeTe/XS2 heterojunctions show significant advantages as photocatalytic materials, providing unique insights for researching and developing this kind of heterojunction.

Unveiling the role of C60-supported vanadium single atoms for catalytic overall water splitting

Designing efficient bifunctional catalysts that can catalyze overall water splitting to generate hydrogen—an attractive, environmentally friendly and renewable energy carrier—is tremendously important to combat the global warming and energy crisis. Here, we report an atomistic-level understanding of the overall water splitting mechanism, 2H2O → 2H2 + O2, mediated by C60-supported vanadium single atoms. Detailed reaction pathways are calculated, and key intermediates with nominal chemical formulas of C60V+(H2O)2 and C60V+O2 are characterized by infrared spectroscopy. When mediated by an isolated V+, the overall water splitting reaction stops due to geometric restrictions with end product V+(OH)2 or V+O(H2O), whereas it can proceed to complete a catalytic cycle in the presence of the C60-support. Our analyses reveal that the vanadium center undergoes several formal oxidation state changes resulting from the unique electron donating/accepting ability of the C60-support, acting as an “electron sponge,” additional to its role in facilitating the hydrogen transfer.

Bifunctions of a Cr hydroxide layer for water splitting over a platinized Au/TiO2 plasmonic photocatalyst under visible light irradiation

Plasmonic water splitting (H2O → H2 + 1/2O2) over a metal-loaded metal oxide under irradiation of a wide range of visible light is an ideal way for H2 production that does not rely on the use of fossil resources. For larger production of H2, cocatalysts having a small hydrogen overpotential such as platinum (Pt) and Rh nanoparticles (NPs) is indispensable; however, these metals induce the back reaction, resulting in low activity for water splitting. In this study, chromium hydroxide (Cr(OH)3) was introduced to gold-titanium(IV) oxide having Pt NPs plasmonic photocatalysts (Au/TiO2-Pt) and the thus-prepared Cr(OH)3/[Au/TiO2-Pt] and related photocatalyst were characterized by using a transmission electron microscope equipped with an energy dispersive X-ray analyzer. Functions of the Cr(OH)3 layer in Cr(OH)3/[Au/TiO2-Pt] were evaluated through photocatalytic reactions under various conditions. The reduction sites of Cr(OH)3/[Au/TiO2-Pt] and the reaction mechanism of water splitting are discussed on the basis of experimental results.

The construction of double type II heterostructure from CdS and Ni-MOF-74 with two structures and enhanced mechanism of photocatalytic water splitting

The construction of double type II heterostructure from CdS and Ni-MOF-74 with two structures and enhanced mechanism of photocatalytic water splitting

Role of the radiations in water splitting for hydrogen generation

Due to environmental pollution and climatic issues, hydrogen is considered a green fuel, which is an innovative area of research. Among various methods, water splitting is one of the best ways to produce hydrogen fuel. The optimization of water splitting is an important experimental factor to get a good yield of hydrogen at the economic level. Among various factors, the selection and application of appropriate radiation are very important issues. Therefore, efforts are made to discuss the application of various radiations (UV, Visible, gamma, X-ray, IR) in water splitting. The role of radiation in the water splitting mechanism is also discussed. The future perspectives and the safety measures are also described in this article. This article will be highly useful to design and optimize water splitting for hydrogen generation; in the future; at a large scale economically.

Plasma-assisted rhodium incorporation in nickel–iron sulfide nanosheets: enhanced catalytic activity and the Janus mechanism for overall water splitting

Rh was incorporated in Fe-doped Ni3S2 nanosheets with the assistance of hydrogen plasma to significantly enhance the HER/OER catalytic activity. The operando evolution behavior and Janus catalytic mechanism of this catalyst were further revealed.