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The aggregate structures of photocatalyst particles are critical for their light absorption and scattering properties and thus significantly impact the photocatalytic performance toward solar hydrogen production. Herein, taking P25 TiO 2 nanoparticles as model photocatalysts, we calculate the optical properties of the aggregates of nanoparticles with the Discrete Dipole Approximation (DDA). A scattering phase function, which can reveal and predict the structural information of photocatalyst particles, is accordingly obtained. Specifically, it is found that the forward scattering is dominant when light is scattered on the particles, and this scattering mode becomes more intense with the increment of the particle size. Our results show that the scattering phase function is also in agreement with the Rayleigh-Gans-Debye (RGD) approximation. • Clusters of TiO 2 nanoparticles are established via fractal aggregation models. • Scattering properties are calculated via Discrete Dipole Approximation. • Forward-scattering dominates the phase function in modeling photocatalysis. • Phase functions agree with the prediction of Rayleigh-Gans-Debye approximation. [ABSTRACT FROM AUTHOR]

Ta3N5 is a promising material for photocatalytic hydrogen production from water because of its suitable band structure for both solar energy collection and overall water splitting, while its application is restricted by severe charge recombination as well as non‐equilibrium redox capabilities. Herein, atomic‐scale N‐doped NaTaO3@Ta3N5 (NNaTaO3@Ta3N5) core‐shell cubes prepared by nitridation of cubic NaTaO3 are reported. The core‐shell heterojunction cubes present efficient and stoichiometric evolution of H2 and O2 from photocatalytic overall water splitting, with a quantum efficiency of 2.18% at 550 nm without any cocatalyst. The success relies on the Ta3N5 shell having a thickness of only ≈5 nm which enables increased lifetimes of the photogenerated charges. Moreover, the core‐shell heterojunction shows a type‐I band alignment that can steer smooth charge flow from NNaTaO3 to Ta3N5, particularly with the assistance of the shared communal Ta atoms at the interface. This efficiency can be further improved to 6.28% by in situ deposition of a Rh@Cr2O3 core‐shell cocatalyst, which is among the highest reported values over Ta3N5‐based photocatalyst. This study offers a promising pathway for the construction of well‐defined heterojunctions with manipulated charge transfer behavior for photocatalytic overall water splitting. [ABSTRACT FROM AUTHOR]

An ideal model composite made of CuS nanosheet (photothermal material) and g-C 3 N 4 was constructed through in-situ assembly procedure, along with integration of dual photochemical effect and photothermal effect. Consequently, optimized CN/CuS composite approaches remarkable photocatalytic performance improved by 44.5 times with regarding to that of pristine CN. This superiority can be assignable to inherent characteristic of CuS as photochemical component, with improved charge separation and enriched surface active-sites. Additionally, the critical contribution of photothermal effect in boosting water photosplitting was also experimentally validated. CuS nanosheet as hot spots enables rapid temperature increment around photocatalysts under visible/near-infrared (NIR) light irradiation. The heat converted from solar is conducive to increase carrier density, accelerate carrier mobility, alleviate onset potential and facilitate surface redox kinetics, so as to promote photocatalytic activity. It is believed that synergetic incorporation of photothermal and photochemical conversion could be expanded to other photocatalytic systems towards effective solar energy conversion. • CuS hot spot was integrated with g-C 3 N 4 in 2D-2D contact by in-situ assembly method. • CuS induced photothermal effect plays a critical role in boosting photocatalytic rate. • Photochemical/photothermal synergistic catalysis boosts H 2 evolution by 44.5 times. [ABSTRACT FROM AUTHOR]

[Display omitted] • A 2D/2D gC 3 N 4 /MoS 2 van der Waals heterojunction photocatalyst was prepared by a novel one-step method. • The type II band arrangement promotes an increase in photogenerated carrier concentration and separation of photogenerated charge carriers. • The in-situ formed heterojunction interface between gC 3 N 4 and MoS 2 boosts H 2 evolution by 3 times. Two-dimensional (2D) heterostructures have proven their efficiency in separating charges. Herein, a gC 3 N 4 /MoS 2 (CN/MoS 2) photocatalyst, in the form of 2D/2D van der Waals heterojunction with a type-II band alignment, was synthesized using a novel one-step method. The resulting in-situ formed heterojunction interface enhances electron transfer from gC 3 N 4 to MoS 2. The CN/MoS 2 photocatalyst exhibits exceptional activity in generating hydrogen from water under simulated solar light. Its hydrogen production rate was 1285 μmol/h/g, which was approximately 3 times higher compared to gC 3 N 4. This superiority is due to a significant increase in photogenerated carrier density and efficient charge separation facilitated by the type-II heterojunction. This study demonstrates a straightforward one-step approach for synthesizing 2D/2D composite photocatalysts, highlighting the effective synergy between different 2D materials in promoting hydrogen generation. [ABSTRACT FROM AUTHOR]

The general moderate reaction condition in solar photocatalytic hydrogen production (i. e., near ambient pressure, room temperature) makes interfacial mass and energy transfer extremely slow, even by employing a cocatalytic material (usually in the form of noble metal nanoparticles or their counterparts). Herein, by fabricating well‐defined Cu@Ni core‐shell nanoplate cocatalyst and further incorporating it with a g‐C3N4 photocatalyst, we demonstrate that interfacial processes could be significantly improved by coupling localized photothermal effect into a cocatalyst. Specifically, Cu nanoplate can induce localized strong hot spots on Ni nanoparticles via a visible‐light‐driven surface plasma resonance effect. As a result, photogenerated electrons transferred from g‐C3N4 to Ni, could be elevated to a more energetic state, leading to a substantially improved photocatalytic activity toward H2 evolution from water. The highest hydrogen generation rate reaches 55 μmol h−1 g−1, 110 times of that pristine g‐C3N4. This work indicates that photoelectric and photothermal effects can be effectively coupled by integrating metal hetero‐nanoparticles. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A hollow NiS/CdS/TiO 2 photocatalyst was prepared by a hydrolysis process. • Photocatalytic activity of TiO 2 was improved by anchoring CdS and NiS. • The synergistic effect of the heterojunction and cocatalyst promote H 2 production. Abstract Noble-metal-free hollow NiS/CdS/TiO 2 (NS/CT) nanohybrid photocatalyst was prepared by a facile hydrolysis combining sulfidation process using metal–organic framework (MOF) as a template. The as-prepared composites were characterized by SEM, TEM, XRD, XPS, UV–vis, and photoelectrochemical techniques. It is found that NS/CT composites with porous hollow structure show significantly enhanced photocatalytic efficiency compare to TiO 2 , or CdS/TiO 2 , or even Pt decorated CdS/TiO 2 photocatalysts, for hydrogen evolution from water upon visible light irradiation. Significantly, NS/CT composite with optimum amount of 30% CdS and 0.3% NiS exhibits the highest photoactivity, with H 2 production rate of 2149.15 µmol·g−1·h−1, which is 23.9 and 2.3 times higher than that of the pure CdS particles and the CdS/TiO 2 nanocomposites, respectively. The superiority of the composites arises from the synergistic effect of the heterojunction for rapid charge separation and the NiS cocatalyst for accelerated surface redox reaction. [ABSTRACT FROM AUTHOR]

Single-atom loading of the non-precious transition metals (M = Ti, V, Mn, and Fe) on the (100) surface of SrTiO 3 (STO) was theoretically investigated to evaluate the hydrogen evolution reaction (HER) with Gibbs free energy for hydrogen adsorption (∆ G H * ). V 1 -STO stood out owing to the ∆ G H * of − 0.08 eV, which was competitive to the metallic Pt with the value of − 0.09 eV. The d band center rationalized well the primary screening of single-atom non-precious transition metals on STO. Furthermore, strain engineering was applied to refine the HER performance of V 1 -STO. The tensile strain increased the ∆ G H * , while the compressed strain decreased the ∆ G H * . A new descriptor of the d orbital splitting (ε d − gap) was proposed to explain the optimization of the HER performance arising from the surface strains. This work conceives a combinational strategy to evaluate the HER performance, and may give guidance for the sequential design of HER catalysts. [Display omitted] • Screen the vanadium atom from four types of non-precious metal atoms to load on SrTiO 3 (100) surface for hydrogen evolution reaction. • Optimize the HER performance of V 1 -STO by further strain engineering. • Propose the material design strategy composed of first using d band center screening for suitable loading single atom type and then applying ε d − gap screening for optimal strain. [ABSTRACT FROM AUTHOR]

Cover Feature: Coupling Photothermal Effect into Efficient Photocatalytic H2 Production by Using a Plate-like Cu@Ni Core-shell Cocatalyst (ChemCatChem 10/2020) Keywords: core-shell structure; photothermal effect; photocatalysis; cocatalyst; H2 evolution EN core-shell structure photothermal effect photocatalysis cocatalyst H2 evolution 2648 2648 1 05/23/20 20200520 NES 200520 B The Cover Feature b shows an ideal photocatalytic process for hydrogen production from water over a composite photocatalyst composed of Cu@Ni core-shell nanoplates and g-C SB 3 sb N SB 4 sb by coupling photothermal effect with photoelectric effect. Core-shell structure, photothermal effect, photocatalysis, cocatalyst, H2 evolution. [Extracted from the article]

• Pd nanocubes integrate on the surface of STO nanocubes at [100] orientation. • Lattice-oriented contact at the interface contributes to fluent charge transfer. • An appropriate Schottky barrier is achieved over smaller Pd nanocubes. • Integration of smaller Pd nanocubes gives better photocatalytic activity. Semiconductor-metal hybrids have been extensively studied for solar-to-hydrogen conversion. Delicate control on surface of cocatalysts and primary photocatalysts and interface therein can remarkably improve the photocatalytic efficiency. Herein, taking size-controlled Pd nanocubes and SrTiO 3 (STO) nanocubes as models, the integration of Pd nanocubes on STO nanocubes (Pd/STO) surface was achieved via an in-situ growth method. The composite photocatalyst presents significant enhancement toward photocatalytic hydrogen production compared to the similar counterpart prepared by simple mechanical self-assembly of Pd and STO, as well as to the pristine STO. The highest hydrogen evolution rate reaches 0.44 mmol h−1 g−1. The success relies on the lattice-oriented growth of Pd nanocubes on STO nanocubes for rapid charge separation from STO to Pd, and accelerated energy and mass exchange on surface of Pd. We believed that the strategy can provide a general guidance to develop more surface and interface-modified metal-semiconductor hybrid systems for hydrogen production. [ABSTRACT FROM AUTHOR]

• The defect-rich one-dimensional MoS 2 hierarchical architecture (1D-DRHA MoS 2) with integrated the advantageous structural features of rich defects and one-dimensional hierarchal morphology was studied for hydrogen evolution reaction. • The 1D-DRHA MoS 2 electrocatalyst exhibited an overpotential of 119 mV at 10 mA cm−2, a Tafel slope of 50.7 mV dec−1, an exchange current density of 1.56 mA cm−2, accompanied by an excellent stability. • Combined experimental evidences and density functional theory calculations demonstrated the incorporation of rich defects and one-dimensional hierarchical structure improved electric conductivity, intrinsic activity, and active sites, which together accounted for the boosted HER performance. Optimizing the activity of layered molybdenum disulfide (MoS 2) toward hydrogen evolution reaction (HER) process is generally achieved by improving the electrical transport, intrinsic activity, and/or the number of active sites. However, simultaneously coupling these factors to achieve remarkable MoS 2 -based electrocatalysts has been seldom reported. Herein, we report a facile approach to the defect-rich one-dimensional MoS 2 hierarchical architecture (1D-DRHA MoS 2), which synergistically integrate the advantageous structural features of rich defects and one-dimensional hierarchal morphology. Toward HER process, the 1D-DRHA MoS 2 electrocatalyst exhibited an overpotential of 119 mV at 10 mA cm−2, a Tafel slope of 50.7 mV dec-1, accompanied by an excellent stability. Notably, the activity is competitive to the state-of-the-art MoS 2 -based electrocatalysts for HER. The combination of experimental evidences and density functional theory calculations demonstrated the incorporation of rich defects and one-dimensional hierarchical structure improved electric conductivity, intrinsic activity, and active sites, which together accounted for the boosted HER performance. [ABSTRACT FROM AUTHOR]