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Graphical abstract Highlights • Ultrathin TiO 2 shell was coated on chalcogenide nanorod as a protecting layer. • The synthesis relies on kinetic control for layer-by-layer deposition of TiO 2. • The heterostructure enables superior activity and stability of solar H 2 evolution. • Charge transfer is controlled by type-II band alignment and tunneling effect. Abstract It has been a subject of intensive research on avoiding photocorrosion of sulfide photocatalysts while retaining their activity for visible-light-driven photocatalysis. Herein, using Cd 0.9 Zn 0.1 S (CZS) nanorod as an example, we report an effective strategy based upon conformal coating of an ultrathin pinhole-free TiO 2 shell, with controllable thickness from 2 to 7 nm, on the nanorod as protecting layer. The synthesis relies on the use of a syringe pump for kinetic control, by which, TiO 2 can grow on the surface of CZS in a layer-by-layer mode. The core–shell heterostructures were found with excellent photocatalytic performance toward solar hydrogen production from a Na 2 S-Na 2 SO 3 aqueous solution. The reaction can stably proceed for 200 h without notable decay of the hydrogen evolution rate. A volcano-type relationship between the mass activity and the shell thickness was gained either in the presence of a cocatalyst or not. The heterostructure with a shell thickness of 2 nm presented the highest H 2 -evolution activity with a quantum efficiency of 19%. However, the one with a shell thickness of 7 nm, instead, was found to be more active, with a quantum efficiency reaching 44%, when 1 wt% NiS x cocatalyst was introduced. It is believed that photogenerated electrons transfer from CZS to TiO 2 , while the holes vanish via quantum-tunneling-induced recombination with the electrons. This work suggests that sulfide photocatalysts with desirable efficiency and corrosion resistance could be achieved by introducing conformal atomic TiO 2 layers. [ABSTRACT FROM AUTHOR]

[Display omitted] • The monolithic photocatalyst based on titanium foam was prepared. • The dual cocatalyst enables better charge transfer and separation efficiency. • CO 2 reduction into CH 4 in a concentrated solar reactor. • Photo-thermal coupling effect improves the conversion efficiency of solar energy. This study is dedicated to solving the problems of low energy utilization and low yield in the conventional photocatalytic CO 2 reduction process. Herein, we constructed a novel concentrated solar (light) reactor and enabled the titanium foam-based monolithic photocatalyst TF@TNT/0.4CoO x -0.1CuO to improve the solar energy utilization efficiency and CO 2 conversion rate by concentrating light and its thermal effect. We found that the yield of CH 4 increased up to 220 times (from 0.53 µmol/cm2 to 116.4 µmol/cm2) when the light intensity of the reactor was increased from 400 mW/cm2 to 4266 mW/cm2 (10.6 times). Meanwhile, the solar-to-fuel conversion efficiency was improved up to 0.35% in the concentrated solar (light) reactor. We further investigated the origin of the photothermal coupling effect with concentrated light through the electrochemical and photochemical measurements. It shows that the concentrated light can further lower the reaction barrier (from 41.62 to 31.51 kJ/mol) and the induced photothermal coupling effect could significantly increase the yield. This provides a valuable strategy for the efficient and environmentally friendly utilization of CO 2 using solar energy. [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]

[Display omitted] • Photo-thermal-magnetic three-field coupling for enhanced CO 2 photo-reduction. • Nickel foam was used as nickel source and catalyst support. • 0.01 wt% Cu/Cu 2 O/HNF exhibited the best catalytic activity and CH 4 selectivity. • The heat of the reaction system came from magnetic-thermal and photo-thermal effects. Aiming at the bottleneck of thermodynamics, kinetics and reaction systems in photothermal catalytic CO 2 reduction conversion, a three-field coupling method based on the efficient utilization of solar energy and the application of a photo-thermal-magnetic three-field was proposed to achieve efficient and highly selective CO 2 conversion. The composite monolithic catalyst with three field response functions and multiple active reaction interfaces was prepared by using photoactive copper supported by nickel foam. The effect of an external alternating magnetic field on photocatalytic CO 2 reduction was studied using a range between 0.005 and 0.1 wt% Cu/Cu 2 O/Ni(OH) 2 /NF as catalysts. The results showed that 0.01 wt% Cu/Cu 2 O/Ni(OH) 2 /NF exhibited the best catalytic activity and CH 4 selectivity under alternating magnetic field enhanced photocatalysis. The main products were CO (6.76 μmol g−1) and CH 4 (167 μmol g−1). The selectivity of CH 4 was 96.1%. The yields of CH 4 using this method were 11 and 6 times higher than the yields obtained with photocatalysis (14.58 μmol g−1) and magnetic-thermal catalysis (26.75 μmol g−1), respectively. According to the analysis of temperature measurements and electrochemical measurements, the surface temperature of the three-field coupled catalyst reaches about 230 °C. Applying an alternating magnetic field can effectively reduce the recombination of photogenerated electron holes. Alternating magnetic field enhanced photocatalytic CO 2 reduction conversion provides a new and promising method for the efficient conversion and utilization of solar energy. [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]