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Charge transfer in a semiconductor is crucial for photocatalytic pure water splitting. Herein, we construct a series of P-doped- g -C 3 N 4 /Fe 2 P/red-P (PCN/Fe 2 P/RP) ternary composite by in-situ phosphorization of a Fe 2 O 3 @C/ g -C 3 N 4 heterojunction. The as-prepared composite show substantially improved photocatalytic activity toward pure water splitting under visible light irradiation without adding any noble metal. The optimized composite containing 15 wt% Fe 2 P presents the best activity, with the H 2 production rate of 429 µmol g−1 h−1, which is 107 and 39 times higher than that of pristine g-C 3 N 4 and P doped g -C 3 N 4 (PCN), respectively. This noble-metal-free photocatalyst presents a solar-to-hydrogen conversion efficiency of about 0.2% for pure water splitting. It is found that water splitting proceeds via a two-electron pathway with simultaneous production of H 2 and H 2 O 2. The improvement relies on the formation of intermediate Fe 2 P for rapid Z-scheme electron transfer from the midgap state of PCN to the valence band of RP. This work provides a versatile method for fabricating noble-metal-free photocatalyst with controlled charge transfer behavior for efficient photocatalytic pure water splitting. [Display omitted] • Efficient P-doped- g -C 3 N 4 /Fe 2 P/red-P photocatalyst is successfully prepared. • Photocatalytic pure water splitting is achieved by two-election Z-scheme mechanism. • Fe 2 P acts as an intermediate layer for rapid Z-scheme electron transfer. • Solar-to-hydrogen conversion efficiency of the composite is about 0.2%. [ABSTRACT FROM AUTHOR]

Z-scheme photocatalysis provides a promising solution to photocatalytic solar water splitting, yet restricted by inferior interfacial charge transfer. Here, we demonstrate a Z-scheme composite photocatalyst made of Fe 2 O 3 , a carbon layer, and g-C 3 N 4 that can achieve efficient hydrogen generation from solar water decomposition. The success relies on in-situ preparation of core-shell Fe 2 O 3 @C structure at the surface of g-C 3 N 4. Carbon as an intermediate layer thus acts as a bridge that significantly accelerates the migration of photogenerated electrons from Fe 2 O 3 conduction band to g-C 3 N 4 valence band. As a result, the highest rate of H 2 generation reaches 5.26 mmol h−1g−1. This activity is approximately 33-time greater than that achieved over pristine g-C 3 N 4 and about 4-time larger than that obtained over a Fe 2 O 3 /g-C 3 N 4 heterojunction without internal carbon layer. This work explicates the potential insight of the composite and paves a promising way to engineer the charge transfer behavior. [Display omitted] • A heterojunction made of Fe 2 O 3 , g-C 3 N 4 , and a carbon interlayer is obtained. • Photocatalytic water splitting proceeds via a Z-scheme mechanism over the catalyst. • The intermediate carbon layer acts as a channel for efficient electron transfer. • The photocatalytic activity for H 2 production is significantly improved. [ABSTRACT FROM AUTHOR]

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]

The feasibility of solar hydrogen production from water has long relied on the activity and stability of a given photocatalyst. In this study, using Cd x Zn 1-x S as a model photocatalyst, we demonstrated that the activity and stability of chalcogenide photocatalyst could be readily adjusted by changing the reaction conditions, including sacrificial reagents, reaction temperature. Our results showed that the combined use of proper sacrificial reagents play a key role against photocorrosion. Under optimized reaction conditions, the photocatalyst remained stable for more than 500 h. Under irradiation from a simulated sun light (light intensity: 789.92 W/m 2 ), the average rate of hydrogen evolution reached 1.43 mmol/h with an energy conversion efficiency from solar to hydrogen of 6.22%. [ABSTRACT FROM AUTHOR]

Abstract: A series of CdS and CdS/CNTs photocatalysts were successfully prepared by hydrothermal method and they were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV–visible optical absorption spectra (UV–Vis), etc. By studying their photocatalytic properties, it is found that, for CdS, photocatalysts prepared in appropriate alkaline environment presented higher hydrogen production activity, reaching 794.6 μmol h−1 g−1; the photocatalytic activity of CdS was obviously enhanced by combining it with CNTs via a special two-step hydrothermal method, and the corresponding hydrogen production rate reached 1.771 mmol h−1 g−1; the photocatalytic activity was further improved by loading co-catalyst NiS, achieving 12.13 mmol h−1 g−1. [Copyright &y& Elsevier]

We report the synthesis of a Z-scheme monolithic photocatalyst in the form of copper foam (CF) supported TiO 2 combining Cu 2 O and Ag nanoparticles (CF@TiO 2 /Cu 2 O-Ag). The designed catalysts with efficient charge separation show superior photocatalytic activity toward CO 2 reduction, with a maximum CO yielding rate of 25.58 μmol‧g-1‧h-1. More importantly, we develop a solar-wind energy complementary device, which enables the strong coupling of the magnetic field into the photocatalytic reaction. Specifically, the in-situ space electric field generated from the wind-driven induced electromotive force further enhances the separation and transportation of photogenerated charge carriers in the Z-scheme system. The productivity of CO in the proof-of-concept device based on the use of CF@TiO 2 /Cu 2 O-Ag catalyst reaches 71.66 μmol‧g-1‧h-1. This study provides an ideal approach for reinforcing photocatalytic CO 2 reduction through muti-field coupling and highlights the prospect of solar-wind energy coupled photocatalysis. [Display omitted] • Preparation of monolithic Z-scheme CF@TiO 2 /0.6Cu 2 O-0.6Ag photocatalyst. • Z-scheme heterostructure enables effective carrier transportation and separation. • Loading of Cu 2 O and Ag promotes photoreduction of CO 2 into CO. • Construction of environmental friendliness solar-wind photocatalytic reactor. • Induced electromotive force raised from magnetic field boosts charge separation. [ABSTRACT FROM AUTHOR]

Solar photocatalytic hydrogen production from water has been regarded as an ideal way addressing world energy and environmental crises. The technology has long relied on the development of an efficient photocatalyst. In addition to its photocatalytic performance, the large-scale production of certain photocatalyst from the viewpoint of particle application remains a challenge yet has received insufficient focus. Herein, we report an efficient and practical batch preparation system based upon hydrothermal method to the scalable production of chalcogenide nanoparticle photocatalyst. Taking the synthesis of Cd 0.5 Zn 0.5 S (CZS) twinned photocatalyst as an example, the outcome of CZS photocatalyst could reach ∼0.8 kg in this batched synthesis, which is about 390 times of the lab-scale production in mass amount. It was found that the twinned structure and visible-light absorption property were well maintained. Although further measurements toward the photocatalytic activity indicate slight decrement on solar H 2 generation compared to the lab-scale synthesized CZS photocatalyst, a high quantum efficiency of about 40.5% at 425 nm remained. The photocatalytic reaction could also stably proceed for 200 h without notable decay of H 2 -evolution rate. This work thus provides a powerful means for facile scaling up the chalcogenide nanoparticle photocatalyst at the kilogram level with both high quality and good reproducibility. [ABSTRACT FROM AUTHOR]

Shape-controlled synthesis of semiconductor nanocrystals enables fine manipulation over their physicochemical properties. In this paper, unique Cd 0.9 Zn 0.1 S tetrapod nanostructures consisting of two different polymorphisms, i.e. , wurtzite and zinc blende, were successfully synthesized via a simple ethylenediamine-assisted solvothermal route. It is found that the temperature determines the formation of the zinc blende-structured seeds, while the ethylenediamine facilitates the subsequent preferential growth of the wurtzite phase arms. Furthermore, the tetrapods, characterized by a type-II staggered band alignment, have shown enhanced photocatalytic performance for H 2 generation from an aqueous solution containing electron donors under visible light irradiation, in comparison to the nanocrystals with distinct morphologies. Our results indicate that coupling different polymorphisms in a nanocrystal may be advantageous for photocatalytic proton reduction over single-crystal photocatalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] Due to structural tunability, high surface area, abundant pore structures, and abundant active sites, covalent heptazine frameworks (CHFs) constructed from heptazine and other molecular blocks are especially prominent. Here, we proposed a reaction-dependent strategy for designing two dimensional CHFs including high-throughput precursors screening, structure generation, and performance evaluation. Assuming that oxamide-like precursors can undergo the same thermal polymerization reaction as producing C 6 N 7 , seven precursors were screened from more than 109 molecules in the ZINC20 database in terms of molecular weight, number of substructures, shape index, and symmetry. Furthermore, CHF-L1 to CHF-L7 were constructed from urea and the seven precursors according to the topologically assembling scheme in thermal polymerization. The designed CHFs had band gaps ranging from 1.89 to 3.10 eV. Among them, CHF-L3 assembled structurally by urea and 1,2,4,5-tetrazine-3,6-dicarboxamide with the smallest bandgap and an oxidative potential bias of 1.38 V for oxygen evolution reaction was screened as the candidate with high oxidative ability. The negative formation energy based on the synthesis route indicated the synthetic feasibility of CHF-L3, and negative cohesive energy as well as the stable structure under ab initio molecular dynamics simulations confirmed the stability of CHF-L3. The present work is expected to provide a powerful design strategy for two-dimensional CHFs design and is broadly applicable to various computational covalent organic framework design systems and experimental studies. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Heterojunction design in a two‐dimensional (2D) fashion has been deemed beneficial for improving the photocatalytic activity of g‐C3N4 because of the promoted interfacial charge transfer, yet still facing challenges. Herein, we construct a novel 2D/2D Cu3P nanosheet/P‐doped g‐C3N4 (PCN) nanosheet heterojunction photocatalyst (PCN/Cu3P) through a simple in‐situ phosphorization treatment of 2D/2D CuS/g‐C3N4 composite for photocatalytic H2 evolution. We demonstrate that the 2D lamellar structure of both CuS and g‐C3N4 could be well reserved in the phosphorization process, while CuS and g‐C3N4 in‐situ transformed into Cu3P and PCN, respectively, leading to the formation of PCN/Cu3P tight 2D/2D heterojunction. Owing to the large contact area provided by intimate face‐to‐face 2D/2D structure, the PCN/Cu3P photocatalyst exhibits significantly enhanced charge separation efficiency, thus achieving a boosted visible‐light‐driven photocatalytic behavior. The highest rate for H2 evolution reaches 5.12 μmol·h–1, nearly 24 times and 368 times higher than that of pristine PCN and g‐C3N4, respectively. This work represents an excellent example in elaborately constructing g‐C3N4‐based 2D/2D heterostructure and could be extended to other photocatalyst/co‐catalyst system. [ABSTRACT FROM AUTHOR]

Abstract: Ni2+ doped Cd1−x Zn x S microsphere photocatalysts were prepared by a new hydrothermal method. Experimental results showed that the doped Ni2+ can not only affect the crystal structure and morphology of Cd1−x Zn x S photocatalysts, but also greatly improve its photocatalytic activity. It was found that 0.1wt% Ni2+ doped Cd0.1Zn0.9S photocatalyst showed the highest activity with the apparent quantum yield of 15.9% at 420nm. The reason for the positive effects of Ni2+ was discussed. [Copyright &y& Elsevier]

Artificial photosynthesis, in which solar energy drives CO2 to produce hydrocarbon fuels, is considered an effective way to solve the increasingly serious energy crisis and mitigate the greenhouse effect. Herein, layered porous Ru‐loaded and La‐doped g‐C3N4 nanosheets (Ru‐LGCNs) were prepared by one‐step calcination, followed by in situ photoreduction deposition of Ru. The layered Ru‐LGCN showed excellent photocatalytic CO2 reformation of methane performance under visible light, and the generation rates of CO, CH3CH3, CH3OH and CH3CH(OH)CH3 were 133, 154, 251 and 133 μmol h−1 g−1, respectively. The reason for the enhanced photocatalytic activity of Ru‐LGCN is the synergistic effect of bimetallic Ru and La. It is worth noting that the doped La can provide a good channel for charge transfer between LGCNs and CO2. This change in the charge behavior of the transport path is beneficial to break the C=O bonds on the active site La and generate methyl radicals on Ru, resulting in the generation of C2+ hydrocarbons. [ABSTRACT FROM AUTHOR]

In this paper, a direct solar photocatalytic water splitting system with surface uniform concentrators (SUCs) is designed. Parameters influencing hydrogen production rates and energy conversion, viz. sacrificial agent concentration, catalyst concentration and circulation speed, are analyzed under typical days. It is found that the system with SUCs has better performances with higher sacrificial agent, higher catalyst concentration and lower speed: double and triple concentration of the sacrificial agent will improve the energy conversion efficiency by 4.52% and 19.35%, respectively; double and triple the photocatalyst concentration will improve the energy conversion efficiency by 81.32% and 200.00%, respectively; energy conversion efficiency under valve-half-closed and the valve-closed conditions are improve by 21.82% and 118.18% comparing with the valve-open condition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Site-selective loading of Pt and CoO x cocatalysts for enhanced CO 2 photoreduction. • Nitrogen-doping was used to introduce and further stabilize oxygen vacancies. • Theoretical calculation simulated the inductive effect of oxygen vacancies. • Well-designed structure was good for the separation of photogenerated carriers. • 0.25 wt% Pt/0.5 wt% CoO x /N-TiO 2 exhibited the best photocatalytic activity. Photocatalysis provides an attractive approach to convert CO 2 into valuable fuels, which yet highly relies on a well-designed photocatalyst with good selectivity and high CO 2 reduction ability. Herein, we report a mild synthesis of mesoporous spherical N-doped TiO 2 photocatalyst with site-selective deposition of redox cocatalysts. Theoretical calculations prove that nitrogen doping favors the formation of oxygen vacancies (V O) in TiO 2 and stabilizes them as well. The combination of ESR characterization, theoretical calculation and photocatalytic tests confirms V O -induced site-selective loading of the redox cocatalysts (Pt, CoO x). The designed composite shows a maximal CH 4 -yielding rate of 409.17 μmol g−1, which is 180 times higher than that of pure TiO 2. Photoelectrochemical and optical measurements indicate that Pt is the key active center for CO 2 adsorption and activation, while CoO x is responsible for H 2 O oxidization and proton transfer. The separation of reaction site and accelerated mass transfer on the catalyst surface largely enhance the conversion efficiency of CO 2. This work provides a strategy to selectively deposit dual cocatalysts on semiconductor surface through introduction of oxygen vacancies for substantially improved photocatalytic reduction of CO 2. [ABSTRACT FROM AUTHOR]

• TiO 2 -graphene-Ta 3 N 5 can be fabricated by ultrasonic-hydrothermal method. • Graphene at the interface contributes to fluent charge transfer. • Improved photocatalytic activity is achieved via a Z-scheme mechanism. • Photocatalytic pure water splitting is experimentally demonstrated. Titanium dioxide (TiO 2)-based photocatalysts are a class of hottest materials in solar water splitting, while limited achievements have been gained to date due to its broad band-gap only responding in UV region and sluggish charge transfer. Here, we reported a ternary TiO 2 -graphene-Ta 3 N 5 hybrid photocatalyst synthesized via an ultrasonic-hydrothermal method. Compared with pristine TiO 2 and Ta 3 N 5 , the prepared TiO 2 -graphene-Ta 3 N 5 present remarkably enhanced photocatalytic pure water splitting behavior with an optimal H 2 -evolution rate of 180 μmol h−1 g−1. In conjunction with systematic characterizations, we demonstrated the boosted photocatalytic performance is ascribed to both improved visible light utilization and charge transfer behavior. Particularly, it is found that water splitting is achieved through a Z-scheme mechanism, in which the two-dimensional lamellar graphene served as a bridge accelerating the electron transfer from TiO 2 to Ta 3 N 5. This work opens avenues to design efficient TiO 2 -based photocatalyst by embedding conducting layer for rapid electron transfer during solar-fuel conversion. Graphiocal Abstract [Display omitted] [ABSTRACT FROM AUTHOR]

We report a facile, one-pot synthesis of spherical Cu/Cu 2 O yolk-shell nanocrystals (Cu/Cu 2 O YSNSs) with tunable morphologies and explored their applications for assisting photocatalytic hydrogen evolution. The success of current synthesis relies on the reduction of Cu(NO 3) 2 by ascorbic acid in the presence of octadecyl trimethylammonium chloride (OTAC) and hexamethylenetetramine (HMTA). It is found that the variation of OTAC concentration would lead to the formation of Cu/Cu 2 O YSNSs with tunable morphologies. The as-prepared Cu/Cu 2 O YSNSs are further anchored by TiO 2 nanoparticles (Degussa P25) to construct Cu/Cu 2 O/TiO 2 nanocomposites for applications in photocatalytic H 2 evolution under simulated sunlight irritation. The resulting metal-semiconductor nanostructures have remarkable photocatalytic activity in H 2 evolution from water-methanol mixtures, with the product rate being almost 97 times greater than that of the pure P25 catalysts. Such improvement should be attributed to the unique hollow structure and the presence of multi-valent copperish species. The current study describes a feasible one-pot strategy to synthesize copperish oxide nanocrystals with tunable yolk-shell morphologies and validates their promising use in as co-catalyst for photocatalytic hydrogen evolution to illustrate the advantage from both the structure and composition. Yolk-shell Cu/Cu 2 O nanospheres with tunable morphologies are prepared in high purity via a one-pot method. By anchoring with TiO 2 nanoparticles (P25), they exhibit excellent photocatalytic activity (~97 times greater than P25 in hydrogen production rate) and long-term durability towards photocatalytic hydrogen evolution, illustrating the structural and morphological advantages. [Display omitted] [ABSTRACT FROM AUTHOR]

The successful phosphorization of gallium indium zinc oxynitride consists of GaInZnON core and InP shell with an ideal type-II band alignment. With efficient charge separation during photocatalytic pure water splitting, the AQE can be up to 10.6% at 430 nm and 13.8% at 350 nm, respectively. • A core-shell GaInZnON@InP heterojunction photocatalyst is prepared. • The heterojunction displays an ideal type-Ⅱ band alignment. • The band alignment enables efficient charge separation. • Photocatalytic overall water splitting with an AQY of 10.6% is achieved. Overall water splitting via solar-driven photocatalysis provides an ideal way to realizing a viable and sustainable hydrogen economy, while the development of efficient photocatalysts remains a grand challenge to date. Herein, we report the successful surface phosphorization of a gallium indium zinc oxynitride (GaInZnON) photocatalyst, which comprises a GaInZnON core and a thin InP shell. The success to the synthesis relies on the rapid diffusion of In from the bulk to the crystal surface and preferential combination of In with P to form an outer layer. The enhanced charge migration was confirmed with characterization and the charge redistribution difference around the heterojunction. The core-shell composite having an ideal type-II band alignment enables efficient charge separation within the particle scale and significantly improved photocatalytic activity toward pure water splitting for simultaneous and stoichiometric H 2 and O 2 evolution. The apparent quantum efficiencies can be up to 10.6% at 430 nm and 13.8% at 350 nm, respectively. Our results suggest that such core-shell GaInZnON@InP architectures hold great potential for efficient and scalable solar hydrogen generation. [ABSTRACT FROM AUTHOR]

• CuO QDs are encapsulated in MIL-125(Ti) via a complexation-oxidation method. • Ternary g-C 3 N 4 /CuO@MIL-125(Ti) enables efficient photocatalytic CO 2 reduction. • CuO QDs are crucial in altering the reaction pathway for the production C2+. • The composite photocatalyst shows good stability and recyclability. Improving the stability of metallic oxide quantum dots (QDs) in a reaction system containing water is crucial for their practical applications in photocatalytic reduction of carbon dioxide. Herein, we use simple complexation-oxidation method to encapsulate CuO QDs in the pores of metal organic framework of MIL-125(Ti), and further combine it with g-C 3 N 4 to form a composite photocatalyst, i.e. , g-C 3 N 4 /CuO@MIL-125(Ti). Benefiting from the protection of the framework of MIL-125(Ti), the composite photocatalyst exhibits significantly improved stability in reaction systems containing water. In addition, due to the close contact of CuO QDs to the active catalytic site of Ti in MIL-125(Ti), the photogenerated electrons in the MIL-125(Ti) and g-C 3 N 4 can be smoothly transferred to the confined CuO QDs, which remarkably enhances the photocatalytic activity of g-C 3 N 4 /CuO@MIL-125(Ti) for photocatalytic CO 2 reduction in the presence of water. An optimization of the photocatalyst has led to the yields of CO, methanol, acetaldehyde and ethanol up to 180.1, 997.2, 531.5 and 1505.7 μmol/g, respectively. This work provides an effective strategy for improving the stability and charge separation property of metallic oxide-QDs modified photocatalyst toward efficient photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]