Redox Reactions In Water Research Articles

Two-Dimensional GeC/MXY (M = Zr, Hf; X, Y = S, Se) Heterojunctions Used as Highly Efficient Overall Water-Splitting Photocatalysts.

Hydrogen generation by photocatalytic water-splitting holds great promise for addressing the serious global energy and environmental crises, and has recently received significant attention from researchers. In this work, a method of assembling GeC/MXY (M = Zr, Hf; X, Y = S, Se) heterojunctions (HJs) by combining GeC and MXY monolayers (MLs) to construct direct Z-scheme photocatalytic systems is proposed. Based on first-principles calculations, we found that all the GeC/MXY HJs are stable van der Waals (vdW) HJs with indirect bandgaps. These HJs possess small bandgaps and exhibit strong light-absorption ability across a wide range. Furthermore, the built-in electric field (BIEF) around the heterointerface can accelerate photoinduced carrier separation. More interestingly, the suitable band edges of GeC/MXY HJs ensure sufficient kinetic potential to spontaneously accomplish water redox reactions under light irradiation. Overall, the strong light-harvesting ability, wide light-absorption range, small bandgaps, large heterointerfacial BIEFs, suitable band alignments, and carrier migration paths render GeC/MXY HJs highly efficient photocatalysts for overall water decomposition.

Te-vacancy defect triggering photocatalytic overall water splitting for MoTe2/GeN Z-scheme heterostructure

Developing proper semiconductor photocatalysts is urgently needed to solve energy and environmental crises. Especially, photocatalysts for water splitting with a Z-scheme mechanism are desirable materials. Herein, a two-dimensional VTe-MoTe2/GeN heterostructure (VTe-HS), including single Te vacancy, is theoretically proved to function as a direct Z-scheme photocatalyst with the wide light-harvesting range, the effective spatial separation for carriers, and the high catalytic activity for water splitting. An enhanced optical absorption coefficient of 105 cm−1 is observed and the absorption edge (∼1.0 eV) is red-shifted into the infrared light region. Separating photogenerated electron–hole pairs enhances the photocatalytic efficiency due to the staggered band alignment. Interlayer charge migration of about 0.154 electrons induces an intrinsic built-in electric field in the heterostructure, allowing forming the Z-scheme mechanism with a reduction potential of –4.01 eV and an oxidation potential of –7.13 eV. Gibbs free energies confirm that water redox reactions can proceed spontaneously under sunshine. Moreover, the Heyrovsky reaction is kinetically more favorable than the Tafel reaction because of a little energy barrier (0.071 eV). These features show that the VTe-HS is a desirable water-splitting photocatalyst, providing a valuable clue to constructing high-efficiency photocatalysts.

Photocatalytic activity of GaSSe/ WTe2 vdW heterstructure nanocatalyst: The first-principles study

Photocatalytic production of hydrogen provides a feasible strategy to solve the energy crisis and environmental pollution problems. In this paper, the bilayer Ga2SSe/WTe2 vdW heterstructure is proposed to be an effective photocatalyst for hydrolysis by first-principle calculations. Structural stability analyses show that the bilayer Ga2SSe/WTe2 vdW heterstructure is energetically and dynamically stable. The electronic properties show that the bilayer Ga2SSe/WTe2 vdW heterstructure belongs to an indirect bandgap semiconductor (1.287 eV), which is conducive to the reduction of the chance of carrier complexation. Photocatalytic performance analysis shows that the energy band edge positions of bilayer Ga2SSe/WTe2 vdW heterstructure are suitable for photocatalytic hydrolysis in the range of PH = 0 ∼ 14. In addition, the bilayer Ga2SSe/WTe2 vdW heterstructure has higher UV and visible light absorption, larger built-in electric field, and smaller carriers, which effectively ensures the effective separation of photogenerated carriers and their rapid migration to the reactive sites for the redox reaction of water. The results provide valuable theoretical guidance for the synthesis of bilayer Ga2SSe/WTe2 vdW heterstructure and its potential application as a hydrolysis photocatalyst.

Screening of novel halide perovskites for photocatalytic water splitting using multi-fidelity machine learning.

Photocatalytic water splitting is an efficient and sustainable technology to produce high-purity hydrogen gas for clean energy using solar energy. Despite the tremendous success of halide perovskites as absorbers in solar cells, their utility for water splitting applications has not been systematically explored. A band gap greater than 1.23 eV, high solar absorption coefficients, efficient separation of charge carriers, and adequate overpotentials for water redox reaction are crucial for a high solar to hydrogen (STH) efficiency. In this work, we present a data-driven approach to identify novel lead-free halide perovskites with high STH efficiency (ηSTH > 20%), building upon our recently published computational data and machine learning (ML) models. Our multi-fidelity density functional theory (DFT) dataset comprises decomposition energies and band gaps of nearly 1000 pure and alloyed perovskite halides using both the GGA-PBE and HSE06 functionals. Using rigorously optimized composition-based ML regression models, we performed screening across a chemical space of 150 000+ halide perovskites to yield hundreds of stable compounds with suitable band gaps and edges for photocatalytic water splitting. A handful of the best candidates were investigated with in-depth DFT computations to validate their properties. This work presents a framework for accelerating the navigation of a massive chemical space of halide perovskite alloys and understanding their potential utility for water splitting and motivates future efforts towards the synthesis and characterization of the most promising materials.

Dual functionality of the BiN monolayer: unraveling its photocatalytic and piezocatalytic water splitting properties.

To achieve scalable and economically viable green hydrogen (H2) production, the photocatalytic and piezocatalytic processes are promising methods. The key to successful overall water splitting (OWS) for H2 production in these processes is using suitable semiconductor catalysts with appropriate band edge potentials, efficient optical absorption, higher mechanical flexibility, and piezoelectric coefficients. Thus, we explore the bismuth nitride (BiN) monolayer using density functional theory simulations, revealing intriguing catalytic properties. The BiN monolayer is a semiconductor with an indirect electronic bandgap (Eg) of 2.08 eV and displays excellent visible light absorption (approximately 105 cm-1). Detailed analyses show that the band edges satisfy the redox potential for photocatalytic OWS via biaxial strain engineering and pH variation. Notably, the solar to hydrogen conversion efficiency (ηSTH) for the BiN monolayer can reach 17.18%, which exceeds the 10% efficiency limit of photocatalysts for economical green H2 production. The obtained in-plane piezoelectric coefficient of e11 = 16.18 Å C m-1 is superior to widely studied 2D materials. Moreover, the generated piezopotential under oscillatory strain stands at 28.34 V, which can initiate the water redox reaction via the piezocatalytic mechanism. This originates from the mechanical flexibility coupled with higher piezoelectric coefficients. The result highlights the BiN monolayer's potential application in photocatalytic, piezocatalytic, and photo-piezo-catalytic OWS.

Unleashing Photocarrier Transport in Mesoporous Single‐Crystalline LaTiO2N for High‐Efficiency Photocatalytic Water Splitting

AbstractLaTiO2N is a promising narrow‐bandgap semiconductor photocatalyst that shows great promise for water redox reactions. However, its performance is often hindered by fast photocarrier recombination events. Herein, LaTiO2N mesoporous single crystals (MSCs) are successfully fabricated via a topotactic conversion route by using the Ruddlesden–Popper compound NaLaTiO4 as the precursor. The LaTiO2N MSCs are characterized by high crystallinity, abundant mesopores, no grain boundaries (GBs), and exposure of (010) and (101) crystal facets. A facet‐assisted photocarrier separation mechanism is identified for these LaTiO2N MSCs which contributes to the much better photocarrier separation than conventional counterparts. By loading proper cocatalysts, LaTiO2N MSCs serve as an efficient photocatalyst for water‐splitting half‐reactions and are capable of photocatalyzing overall water‐splitting reactions, delivering an impressive apparent quantum efficiency (AQE) as high as 65.07% at 420 ± 20 nm for O2‐evolution and a solar‐to‐hydrogen (STH) efficiency as high as 0.012% for solar‐driven overall water splitting. These findings not only highlight the grain‐boundary‐free MSCs with peculiar crystal‐facet exposure as highly active photocatalysts for particulate photocatalysis but also provide a rational design approach for developing efficient photocatalysts.

High‐Performance Fully Stretchable Moist‐Electric Generator

AbstractThe emerging moist‐electric generation that can harvest energy from the atmosphere moisture to power the next‐generation wearable electronics has attracted great attention recently. However, currently developed moist‐electric generators (MEGs) are hard to be fully stretchable owing to the lack of essential material properties and the restriction of the device construction. Here, stretchable hygroscopic ionic hydrogel and carbon black‐coated cotton knitted fabric are employed with a pair of symmetric Cu electrodes on top and bottom to fabricate a fully stretchable moist‐electric generator (FSMEG). The prepared FSMEG simultaneously achieves outstanding stretchability of 400%, sustained short‐circuit current of 50 µA, and open‐circuit voltage of 0.3 V, demonstrating superior comprehensive performances among current MEGs. The remarkable performances of FSMEG can be ascribed to the decreased crystallinity of ionic hydrogel and the synergistic effect of water evaporation force and redox reaction on electrodes. Of great importance is that large‐scale integration of FSMEG units is capable of driving electronics including calculators, light‐emitting‐diodes, and even cell phones. Beyond power generation, FSMEG also successfully exhibits practical application in self‐powered pressure sensing and weight identification. The optimal properties and design concepts of FSMEG provide new insight for designing next‐generation high‐performance hydroelectric harvesting devices with wide applications.

Recent advances in Bio-mass by electrochemically strategies generated hydrogen gas production: Environmentally sustainable technologies innovation

The potential of green hydrogen as in transitioning to a free pollution energy infrastructure. Green hydrogen gas is produced using renewable energy sources, typically through the process of electrolysis, and is considered environment friendly because it does not emit carbon dioxide when produced. While solar water redox reaction using photochemical and electrochemical methods is an elegant way to harvest green hydrogen production, it can be challenging to make this process economically competitive, especially for low-cost products like hydrogen. To address this challenge, the proposes a solution, which is to produce hydrogen during the photoelectrochemical process. In this demonstration of the (photo)electrochemically generated hydrogen (H2) for the homogeneous and hydrogenation. The coupled process offers greater stability compared to direct electrochemical hydrogenation and it provides more flexibility in controlling the chemical reactions involved. Overpotential refers to the extra energy required to drive a reaction and coupling the processes can help minimize this overpotential. An overall ∼58% conversion of the produced hydrogen is confirmed for this process, indicating the efficiency of the approach. Additionally, a techno-economic assessment of the proa strategy to make green hydrogen production economically competitive by co-producing value-added chemicals, using ascorbic acid. This approach enhances the economic feasibility of green hydrogen production but also adds value to the process by producing valuable chemical products.

Intriguing type-II g-GeC/AlN bilayer heterostructure for photocatalytic water decomposition and hydrogen production

Adapting two-dimensional (2D) van der Walls bilayer heterostructure is an efficient technique for realizing fascinating properties and playing a key role in solar energy-driven water decomposition schemes. By means of first-principles calculations, this study reveals the intriguing potential of a novel 2D van der Walls hetero-bilayer consisting of GeC and AlN layer in the photocatalytic water splitting method to generate hydrogen. The GeC/AlN heterostructure has an appropriate band gap of 2.05 eV, wherein the band edges are in proper energetic positions to provoke the water redox reaction to generate hydrogen and oxygen. The type-II band alignment of the bilayer facilitates the real-space spontaneous separation of the photogenerated electrons and holes in the different layers, improving the photocatalytic activity significantly. Analysis of the electrostatic potential and the charge density difference unravels the build-up of an inherent electric field at the interface, preventing electron–hole recombination. The ample absorption spectrum of the bilayer from the ultra-violet to the near-infrared region, reaching up to 8.71 × 105/cm, combined with the resiliency to the biaxial strain, points out the excellent photocatalytic performance of the bilayer heterostructure. On top of rendering useful information on the key features of the GeC/AlN hetero-bilayer, the study offers informative details on the experimental design of the van der Walls bilayer heterostructure for solar-to-hydrogen conversion applications.

ZnO for Photoelectrochemical Hydrogen Generation

The rise in the Earth’s surface temperature on an annual basis has stimulated scientific and engineering interest in developing and implementing alternative energy sources. Besides cost, the main requirements for alternative energy sources are renewability and environmental friendliness. A prominent representative that allows the production of “green” energy is the conversion of solar photons into a practical energy source. Among the existing approaches in solar energy conversion, the process of photoelectrochemical (PEC) hydrogen extraction from water, which mimics natural photosynthesis, is promising. However, direct decomposition of water by sunlight is practically impossible since water is transparent to light waves longer than 190 nm. Therefore, applying a photoelectrochemical process using semiconductor materials and organic compounds is necessary. Semiconductor materials possessing appropriately positioned valence and conduction bands are vital constituents of photoelectrodes. Certain materials exhibit semiconductor characteristics that facilitate the reduction-oxidation (RedOx) reaction of water (H2O) under specific circumstances. ZnO holds a unique position in the field of photocatalysis due to its outstanding characteristics, including remarkable electron mobility, high thermal conductivity, transparency, and more. This article offers an overview of studies exploring ZnO’s role as a photocatalyst in the generation of hydrogen from water.

Electronic properties, quantum capacitance and photocatalyst for water splitting of Sc2CO2 MXene under uniaxial strain

AbstractMXenes have wide applications because of the structural flexibility and compositional diversity. Quantum capacitance, electronic and photocatalytic properties of Sc2CO2 monolayer under uniaxial strains are investigated by first‐principles calculation. Sc2CO2 monolayer can withstand stress up to 13.96 N/M and about 14% tensile uniaxial strain limit. Sc2CO2 undergoes a transition from semiconductor to metal at −15% uniaxial strain. Sc2CO2 under uniaxial strains are only used for the water reduction at pH = 0. Sc2CO2 under uniaxial strains of −10%, −7%, −3%, 0%, and 4% within the appropriate pH scope are potential photocatalysts for water redox reaction. Sc2CO2 with −15% uniaxial strain is promising anode material, and Sc2CO2 with tensile uniaxial strain is more potential cathode material. Wide voltage improves the top quantum capacitance at negative bias under uniaxial strain and keeps the type of electrode materials. Quantum capacitance of Sc2C with mixed termination (Sc2CO0.59F1.19(OH)0.22) under uniaxial strain is explored. The introduction of uniaxial strain and mixed termination has little effect on the electrode type of Sc2CO2 MXene.

First-principles study on photocatalytic properties of janus monolayer MoSi2N2P2 and MoSi2P2As2

Two Janus two-dimensional monolayer MoSi2N2P2 and MoSi2P2As2 are constructed based on monolayer MoSi2N4. High structural stability of such materials are confirmed by the phonon dispersion spectrums. The MoSi2N2P2 and MoSi2P2As2 monolayers are indirect and direct semiconductors, respectively. For conventional water splitting photocatalysis, band gaps bigger than 1.23 eV are demanded for straddling the water redox potential, causing a waste of infrared part of solar energy. Fortunately, with band gaps smaller than 1.14 eV, the present Janus materials can provide sufficient driving force for water redox reactions on the separate sides due to the different electrostatic potential. More interestingly, these materials show strong absorption on visible light, ultraviolet light, and especially on infrared light. Finally, the redox ability can be furthermore modulated by pH value. These results indicate that the presently predicted Janus materials are expected as candidates of high-efficiency photocatalysis for water decomposition.

First-principles study for the electric field influence on electronic and optical properties of AlN/g-C3N4 heterostructure

Constructing a heterostructure and applying an external electric field are effective methods for enhancing photocatalytic efficiency. In this study, we systematically investigate the electronic and optical properties of an AlN/g-C3N4 heterostructure under varying electric fields using first principles. Our findings indicate that the AlN/g-C3N4 heterostructure demonstrates high stability, and van der Waals (vdW) interactions exist between the interfaces. Compared with monolayers AlN and g-C3N4, the reduced bandgap of AlN/g-C3N4 enhances electron escape ability. Furthermore, we observe that the bandgap of AlN/g-C3N4 reduces when an electric field is applied and the band alignment changes. Importantly, −0.4 V/Å AlN/g-C3N4 is not only a type-II heterostructure, forming a built-in electric field, but it also has a band alignment that spans the redox reaction of water. Consequently, the compound rate of electron–hole pairs substantially reduces, enhancing the possibility of AlN/g-C3N4 photocatalytic water splitting. Our findings provide a theoretical foundation for related experimental preparations.

Solar lighting systems applied in photocatalysis to treat pollutants – A review

Abstract This work summarizes the different natural lighting systems applied for pollutant treatment systems using photocatalysis. The principles and fundamentals of the technologies used are revisited and examples of technologies most used for treatment either at the laboratory or at the pilot plant level are disclosed. This unveils a general panorama of treatment technologies via photocatalysis, using natural sunlight as an illumination source. Aside from these concentrated solar power systems that are inviable for photocatalytic aqueous treatments, reported scientific works are shown about heliostats, parabolic troughs, Fresnel lenses, and direct illuminated systems. As a valuable result of this review, the power used in photocatalytic systems requires higher attention not only in these systems but in laboratories and prototypes. Photocatalysts and their countless configuration variants are limited due to the potential barriers in particle borders, interfaces, and surfaces to cause redox reactions in water and pollutant target molecules. These factors reduce photocatalyst efficiencies for converting light energy to useful electron pair charge carriers for water treatments. The use of solar concentration systems applied to photocatalytic treatment systems can generate enough charge carriers, improving the efficiency of the systems, and making it feasible to scale up various configurations of this treatment pathway. Subsequently, the photocatalyst material and light are both important.

Dual functional WO3/BiVO4 heterostructures for efficient photoelectrochemical water splitting and glycerol degradation.

Dual functional heterojunctions of tungsten oxide and bismuth vanadate (WO3/BiVO4) photoanodes are developed and their applications in photoelectrochemical (PEC) water splitting and mineralization of glycerol are demonstrated. The thin-film WO3/BiVO4 photoelectrode was fabricated by a facile hydrothermal method. The morphology, chemical composition, crystalline structure, chemical state, and optical absorption properties of the WO3/BiVO4 photoelectrodes were characterized systematically. The WO3/BiVO4 photoelectrode exhibits a good distribution of elements and a well-crystalline monoclinic WO3 and monoclinic scheelite BiVO4. The light-absorption spectrum of the WO3/BiVO4 photoelectrodes reveals a broad absorption band in the visible light region with a maximum absorption of around 520 nm. The dual functional WO3/BiVO4 photoelectrodes achieved a high photocurrent density of 6.85 mA cm-2, which is 2.8 times higher than that of the pristine WO3 photoelectrode in the presence of a mixture of 0.5 M Na2SO4 and 0.5 M glycerol electrolyte under AM 1.5 G (100 mW cm-2) illumination. The superior PEC performance of the WO3/BiVO4 photoelectrode was attributed to the synergistic effects of the superior crystal structure, light absorption, and efficient charge separation. Simultaneously, glycerol plays an essential role in increasing the efficiency of hydrogen production by suppressing charge recombination in the water redox reaction. Moreover, the WO3/BiVO4 photoelectrode shows the total organic carbon (TOC) removal efficiency of glycerol at about 82% at 120 min. Notably, the WO3/BiVO4 photoelectrode can be a promising photoelectrode for simultaneous hydrogen production and mineralization of glycerol with a simple, economical, and environmentally friendly approach.

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.

Photocatalytic Overall Water Splitting over PbTiO3 Modulated by Oxygen Vacancy and Ferroelectric Polarization.

Ferroelectric materials hold great promise in the field of photocatalytic water splitting due to their spontaneous polarization that sets up an inherent internal field for the spatial separation of photogenerated charges. The ferroelectric polarization, however, is generally accompanied by some intrinsic defects, particularly oxygen vacancies, whose impact upon photocatalysis is far from being fully understood and modulated. Here, we have studied the role of oxygen vacancies over the photocatalytic behavior of single-domain PbTiO3 through a combination of theoretical and experimental viewpoints. Our results indicate that the oxygen vacancies in the negatively polarized facet (001) are active sites for water oxidation into O2, while the defect-free sites prefer H2O2 as the oxidation product. The apparent quantum yield at 435 nm for photocatalytic overall water splitting with PbTiO3/Rh/Cr2O3 is determined to be 0.025%, which is remarkable for single undoped metal oxide-based photocatalysts. Furthermore, the strong correlation among oxygen vacancies, polarization strength, and photocatalytic activity is properly reflected by charge separation conditions in the single-domain PbTiO3. This work clarifies the crucial role of oxygen vacancies during photocatalytic reactions of PbTiO3, which provides a useful guide to the design of efficient ferroelectric photocatalysts and their water redox reaction pathways.

Tunable Photocatalytic Water Splitting Performance of Armchair MoSSe Nanotubes Realized by Polarization Engineering.

The photocatalytic properties of Janus transition metal dichalcogenide (TMD) nanotubes are closely correlated with the electrostatic potential difference between their inner and outer surfaces (ΔΦ). However, due to some distraction from the tubular structures, it remains a great challenge to calculate their ΔΦ directly. Here, we creatively work out the ΔΦ of Janus MoSSe armchair single-walled nanotubes (A-SWNTs) with their corresponding building block models by first-principles calculations. The ΔΦ increases as the diameter reduces. After considering ΔΦ, we find that all of these MoSSe A-SWNTs possess suitable band-edge positions required for water redox reactions and high solar-to-hydrogen (STH) conversion efficiencies. The built-in field induced by the ΔΦ promotes the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) to proceed separately on the inner and outer surfaces. Especially, the photoexcited carriers exhibit adequate driving forces for OER and HER. Besides, constructing a double-walled nanotube can dramatically increase ΔΦ, which also further improves the separation and redox capacity of photoexcited carriers as well as the STH conversion efficiency. Moreover, all of these MoSSe armchair nanotubes have outstanding optical absorption in the visible light range. Our studies provide an effective strategy to improve the photocatalytic water-splitting performance of Janus TMD nanotubes.

Oxygen vacancy rich α-MnO2 @B/O-g-C3N4 photocatalyst: A thriving 1D-2D surface interaction effective towards photocatalytic O2 and H2 evolution through Z-scheme charge dynamics

Herein, we have prepared a 1D-2D junction based Oxygen Vacancy rich α-MnO2@B/O-g-C3N4 photocatalyst by using 1D α-MnO2 nanorods over 2D nanosheets of boron, oxygen co-doped exfoliated graphitic carbon nitride (BOCN). The important feature of the above composite material is the availability of oxygen vacancy as well as the presence of dual oxidation state of Mn (Mn4+, Mn3+) which enhances surface activity as well as chemical reaction output of the material. Among the synthesized materials α-MnO2@B/O-g-C3N4 (MBOCN-20) shows best photocatalytic activity by following Z-Scheme charge dynamics towards water oxidation (295.1 μmol h−1) and reduction (560.1 μmol h−1) reactions in presence of methanol (hole scavenger) and AgNO3 (electron scavenger) as sacrificial agent. However, 44.2 and 86.5 μmol h−1 of O2 and H2 evolution was observed in absence of any sacrificial agent. This analysis will confer a valuable blue-print to construct stimulating photocatalysts to achieve the paramount performance towards photocatalytic water redox reaction.

LaNbON2 mesoporous single crystals with expedited photocarrier separation for efficient visible-light-driven water redox reactions

Combining structural coherence and large porosity, semiconducting porous single crystals (PSCs) warrant a great potential as photocatalysts. High photocarrier mobility can be realized in PSCs because of a deficiency in grain boundaries, which in turn greatly alleviates photocarriers’ recombination. The large porosity of PSCs not only provides plenty of accessible surfaces to accommodate catalytic reaction sites but also fortifies photon-matter interplay by reflecting and scattering photons. In this work, taking LaNbON2 PSCs as an example, we demonstrate the importance of PSCs in activating otherwise almost inactive photocatalyst. Compared to conventional inert LaNbON2, LaNbON2 PSCs exhibit exceptional activity for photocatalytic water redox reactions, delivering a high apparent quantum efficiency, i.e. 6.3% and 10.2% at 420 ± 20 nm for H2- and O2-evolution reactions, respectively. A Z-scheme system containing LaNbON2 PSCs has succeeded in overall water splitting (H2/O2 molar ratio 2:1) with high stability under visible light illumination (λ ≥ 420 nm).