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A Z-scheme BiVO 4 /NiCo 2 O 4 (BVO/NCO) heterojunction structure was constructed by modifying optimal ultrathin nickel–cobalt (NiCo 2 O 4) spinel nanosheets on BiVO 4 as an efficient photocatalyst toward water oxidation, which deliver an excellent photocatalytic O 2 evolution performance of 1640.9 μmol∙g−1∙h−1 by reducing the energy barriers and enhancing the separation and transfer of photogenerated carriers. [Display omitted] The sluggish water oxidation process is a severe obstacle for solar-driven water splitting. Therefore, it is imperative to develop a suitable photocatalyst with reduced energy barrier for strong oxidation. In this study, a Z-scheme BiVO 4 /NiCo 2 O 4 (BVO/NCO) heterojunction system was designed by decorating ultrathin nickel–cobalt (NiCo 2 O 4) spinel nanosheets on BiVO 4 as an efficient photocatalyst for water oxidation. The unique structure of the system significantly reduced the energy barrier and improved the oxidation ability of BiVO 4 to efficiently enhance the separation and transfer of the photogenerated carriers. Thus, the photocatalyst delivered an excellent O 2 evolution performance of 1640.9 μmol∙g−1∙h−1 and showed 124% improved efficiency as compared to pristine BiVO 4 and a quantum efficiency of 5.39% at 400 nm for O 2 evolution. Additionally, the theoretical calculations revealed that the formation of *OOH was the rate-determining step for water oxidation. The decoration with NiCo 2 O 4 significantly reduced the energy barrier between *O and *OOH, which eventually improved the photocatalytic performance of BVO/NCO. The results hold great promise for the potential application of spinel-based materials in efficient photocatalytic O 2 evolution and offer fundamental insights into the design of efficient water oxidation heterojunctions. [ABSTRACT FROM AUTHOR]

• CdS under-layer reduces the recombination at Ag 2 S/FTO interface. • Photoinduced charge carrier dynamics of FTO/CdS/Ag 2 S has been studied. • CdS under-layer raise 52% PCE of Ag 2 S solar cell. [Display omitted] The recombination of photoinduced charge carriers is detrimental to the photovoltaic performance of solar cells. In this work, we used CdS as an under-layer to reduce the recombination of photoinduced charge carriers at the Ag 2 S/FTO (F-doped SnO 2) interface. The CdS under-layer was deposited onto an FTO substrate using a facile chemical bath deposition (CBD) method. By controlling the thickness of the CdS film between Ag 2 S and FTO, the recombination of photoinduced charge carriers was successfully suppressed. The effect of the CdS under-layer on the charge carrier recombination was carefully evaluated by transient surface photovoltage (TSPV) measurements, electrochemical impedance spectroscopy (EIS) and a photoelectrochemical method. The power conversion efficiency (PCE) of solar cell devices with a 40 nm CdS under-layer is 1.16%, which is ~52% enhancement compared to those of FTO/Ag 2 S-based solar cell devices. Our work may provide a useful strategy to suppress photoinduced charge carrier recombination at the electrode and absorber semiconductor interface. [ABSTRACT FROM AUTHOR]

A well-ordered highly crystalline g-C 3 N 4 nanorods (CNR) is rationally tailored by molten salt-assisted anti-defect engineering for efficient artificial photosynthesis of H 2 O 2. [Display omitted] • Highly crystalline and well-ordered g-C 3 N 4 nanorods are tailored. • Molten salt-assisted preparation of highly crystalline organic polymeric materials. • Anti-defect engineering promotes charge separation and transfer. • The H 2 O 2 generation rate reaches 1.58 mmol g-1h−1 only using air as oxygen source. • Molten salt-assisted anti-defect engineering to improve photocatalytic activity. Graphite carbon nitride (g-C 3 N 4) is widely recognized as one of the most popular catalysts for photocatalytic hydrogen peroxide (H 2 O 2) production. However, it is often overlooked that general g-C 3 N 4 materials contain numerous dangling bonds and defects, which serve as recombination centers for photogenerated carriers and significantly hinder their catalytic activity. Herein, we present a novel approach to address this issue by rationally tailoring well-ordered g-C 3 N 4 nanorods (CNR) through molten salt-assisted anti-defect engineering. The resulting highly crystalline CNR demonstrates high efficiency in the artificial photosynthesis of H 2 O 2. Experimental results indicate that enhancing the crystallinity of g-C 3 N 4 while reducing the defect concentration effectively promotes charge separation and transport. As a result, it exhibits a remarkable H 2 O 2 generation rate of 1.58 mmol g-1h−1 using air as the oxygen source, accompanied by an apparent quantum yield of 18.00 % (λ = 400 nm). The excellent photocatalytic performance of CNR surpasses that of all previously reported pristine g-C 3 N 4 materials. This work sheds light on the effectiveness of molten salt-assisted anti-defect engineering in improving catalyst activity, with potential applications in solar cells, sensor devices and other catalytic systems. [ABSTRACT FROM AUTHOR]

A fantastic 2D/1D hierarchical layered ZnIn 2 S 4 /TiO 2 hetero-structure is reported as an efficient catalyst for in- situ H 2 O 2 production via 2-electrons oxygen reduction (ORR) process and be activated to high concentration hydroxyl radical (•OH) for water purification under visible light irradiation. [Display omitted] • Solar-driven H 2 O 2 synthesis to purify water via cascade reaction. • A fantastic 2D/1D hierarchical layered heterojunction of ZnIn 2 S 4 /TiO 2. • ZnIn 2 S 4 effectively promote the activation of in- situ generated H 2 O 2. • The superior H 2 O 2 production rate arrives 1530.59 μmol h−1 g−1. Hydrogen peroxide (H 2 O 2) is a significant green oxidant for environment and new energy, especially for Fenton-like system. Onsite production and sustainable consumption of H 2 O 2 are the two critical challenges. Here, a fantastic 2D/1D hierarchical layered ZnIn 2 S 4 /TiO 2 heterojunction is reported as an efficient catalyst for in- situ H 2 O 2 production via 2-electrons oxygen reduction (ORR) process and be rapidly activated to high concentration hydroxyl radical (•OH) for water purification under visible light irradiation. The high-quality catalyst enables superior H 2 O 2 production rate of 1530.59 μmol h−1 g−1 with an external quantum efficiency of 10.39% illuminated at 400 nm, is much higher than that of reported photocatalysts. The bimetallic sulfide ZnIn 2 S 4 can effectively promote the activation of H 2 O 2 due to the unsaturation of sulfur atoms, so that the wastewater containing tetracycline (50 ppm) can be degraded by 90% only within 60 min by ZnIn 2 S 4 /TiO 2 via this cascade reaction. This work provides a novel strategy and ZnIn 2 S 4 -based catalyst for photocatalytic Fenton-like reaction. [ABSTRACT FROM AUTHOR]