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The photocatalytic nitrogen reduction reaction (NRR) in aqueous solution is a green and sustainable strategy for ammonia production. Nonetheless, the efficiency of the process still has a wide gap compared to that of the Haber–Bosch one due to the difficulty of N2 activation and the quick recombination of photo-generated carriers. Herein, a core-shell Bi@Bi2MoO6 microsphere through constructing Schottky junctions has been explored as a robust photocatalyst toward N2 reduction to NH3. Metal Bi self-reduced onto Bi2MoO6 not only spurs the photo-generated electron and hole separation owing to the Schottky junction at the interface of Bi and Bi2MoO6 but also promotes N2 adsorption and activation at Bi active sites synchronously. As a result, the yield of the photocatalytic N2-to-ammonia conversion reaches up to 173.40 μmol g−1 on core-shell Bi@Bi2MoO6 photocatalysts, as much as two times of that of bare Bi2MoO6. This work provides a new design for the decarbonization of the nitrogen reduction reaction by the utilization of renewable energy sources. [ABSTRACT FROM AUTHOR]

Self-powered photodetectors, requiring no external bias, offer distinct advantages that render them ideal for a broad spectrum of applications. Efficient carrier separation and collection stand as foundational elements in the operation of these photodetectors. In this study, we delve into the refinement of Cu2O/ZnO heterojunction photodetectors. By varying the thickness of the ZnO layer, we controlled the separation and capture of carriers at the heterojunction, thus achieving adjustable photodetector performance. Our experimental findings reveal pronounced performance trends related to different wavelength bands, with particular significance in the ultraviolet and visible exploration. We observe a distinctive pattern marked by an initial performance increase followed by a subsequent decline. This intriguing phenomenon implies that meticulous control over carrier separation and collection within the heterojunction can be realized by fine-tuning the transmission distance, ultimately allowing us to adjust the photodetector's responsivity. [ABSTRACT FROM AUTHOR]

Interface engineering of the hole transport layer in CH3NH3PbI3 photodetectors has resulted in significantly increased carrier accumulation and dark current as well as energy band mismatch, thus achieving the goal of high-power conversion efficiency. However, the reported heterojunction perovskite photodetectors exhibit high dark currents and low responsivities. Herein, heterojunction self-powered photodetectors, composed of p-type CH3NH3PbI3 and n-type Mg0.2Zn0.8O, are prepared through the spin coating and magnetron sputtering. The obtained heterojunctions exhibit a high responsivity of 0.58 A/W, and the EQE of the CH3NH3PbI3/Au/Mg0.2Zn0.8O heterojunction self-powered photodetectors is 10.23 times that of the CH3NH3PbI3/Au photodetectors and 84.51 times that of the Mg0.2ZnO0.8/Au photodetectors. The built-in electric field of the p-n heterojunction significantly suppresses the dark current and improves the responsivity. Remarkably, in the self-supply voltage detection mode, the heterojunction achieves a high responsivity of up to 1.1 mA/W. The dark current of the CH3NH3PbI3/Au/Mg0.2Zn0.8O heterojunction self-powered photodetectors is less than 1.4 × 10−1 pA at 0 V, which is more than 10 times lower than that of the CH3NH3PbI3 photodetectors. The best value of the detectivity is as high as 4.7 × 1012 Jones. Furthermore, the heterojunction self-powered photodetectors exhibit a uniform photodetection response over a wide spectral range from 200 to 850 nm. This work provides guidance for achieving a low dark current and high detectivity for perovskite photodetectors. [ABSTRACT FROM AUTHOR]

In the work, visible-light-driven ZnIn 2 S 4 /TiO 2-x nanotube arrays were fabricated by defect-induced bandgap engineering, leading to high visible light responsive, and combining ZnIn 2 S 4 cocatalyst to improve separation of photogenerated carriers, thus enhancing photocatalytic H 2 production. [Display omitted] • A visible-light-driven ZnIn 2 S 4 /TiO 2-x nanotube arrays for fabricating the highly efficient photocatalysts is proposed. • The in-plane oxygen vacancies induce the high visible light responsive of TiO 2-x. • ZnIn 2 S 4 /TiO 2-x nanotube arrays prompt synergistic regulations of both absorption and separation benefits. • ZnIn 2 S 4 /TiO 2-x nanotube arrays exhibit high and stable photocatalytic hydrogen evolution. Photocatalytic H 2 evolution provides an upcoming route for the production of clean fuel via the conversion of solar energy. TiO 2 , as a potential semiconductor material, is restricted by its faint absorption of visible light, thus limiting its application in water splitting. Herein, high visible light responsive ZnIn 2 S 4 /TiO 2-x nanotube arrays for photocatalytic hydrogen evolution were fabricated by two-step reaction. ZnIn 2 S 4 /TiO 2-x nanotube arrays exhibited the photo response from UV to visible-light region due to the introduction of oxygen vacancies and visible-light driven ZnIn 2 S 4. Moreover, the heterojunction improved the separation of photogenerated carriers and boosted the electron transfer from ZnIn 2 S 4 to TiO 2-x , thereby increasing the longevity of active electrons, which enhanced the photocatalytic activity for hydrogen evolution. An outstanding H 2 production rate of 581.1 μmol h−1 g−1 was obtained and an apparent quantum yield (AQY) up to ∼ 1.42% was achieved. This work demonstrates that the defect-induced bandgap engineering of semiconductor photocatalysts is a potential way to extend the optical absorption property of TiO 2 to visible light even or NIR and enhance the photocatalytic activity. [ABSTRACT FROM AUTHOR]

The photocatalytic hydrogen evolution (PHE) offers a promising and sustainable route to fuels and feedstocks from solar energy. Ti 3 C 2 MXene as a highly active and stable earth-abundant material has been employed in photocatalytic hydrogen production due to its excellent conductivity and effective activation of H 2 O molecules. Herein, a synergistic strategy, via introducing atomic-thickness Ti 3 C 2 MXene to tune the defect structure of the ultrathin ZnIn 2 S 4 nanosheets, is reported to improve the PHE activity. By using microstructure characterization and DFT calculation, we reveal the generation of sulfur vacancies (S vac) on the photocatalysts and the improvement of adsorption property for reactant H 2 O molecules at the surface of ultrathin 2D/2D Ti 3 C 2 / S vac -ZnIn 2 S 4 heterojunction. During the reaction, the synergies between sulfur vacancies and Ti 3 C 2 MXene affect the absorption of light, the separation of carriers, and the reaction of H 2 O molecules, thus improving the PHE rate up to 1435.31 μmol·g−1·h−1 with 6.3 times higher than that of S vac -ZnIn 2 S 4 nanosheets (229.16 μmol·g−1·h−1). This work stresses the great importance of synergistic modulation for promoting photocatalytic hydrogen evolution. [Display omitted] [ABSTRACT FROM AUTHOR]