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[Display omitted] • Z-scheme mechanism was demonstrated by ESR characterizations. • The high photocatalytic activity is owing to the successful fabrication of Z-scheme heterojunction and efficient charge separation. • Direct Z-scheme system enhances the separation of photogenerated charge carriers. • 0D/2D Zn-AgIn 5 S 8 QDs/α-Fe 2 O 3 heterostructures exhibit the efficient photocatalytic H 2 generation. Multinary sulfide quantum dots (QDs) have exhibited outstanding advantages including large surface areas, unique optical properties and adjustable band gap, which are beneficial for visible-active photocatalysis. However, the use of QDs also brings about serious issues of charge recombination and particle agglomeration. Here, a rational design of direct 0D/2D Z-scheme heterojunction of Zn-AgIn 5 S 8 /α-Fe 2 O 3 is described. Appropriate band alignment is conducive to the construction of Z-scheme heterostructures, thus enhancing the redox ability of the semiconductors and inhibiting the charge recombination. Simultaneously, the zeta potential differences between the two semiconductors can make them achieve a close interface contact by electrostatic adsorption and then the 0D Zn-AgIn 5 S 8 (ZAIS) QDs can be dispersed uniformly on 2D α-Fe 2 O 3 nanosheets, which can reduce the agglomeration of QDs. At the same time, the advantages of large specific surface area and short electron transmission path of QDs can also be exerted. Meanwhile, α-Fe 2 O 3 nanosheets with high conductivity can rapidly lead out the photogenerated charge carriers and thus suppress the recombination of the electrons and holes in QDs. The optimum nanocomposites with 3 wt% α-Fe 2 O 3 nanosheets display a photocatalytic H 2 evolution rate of 1.7 mmol g−1 h−1, 3.5 times to that of pure QDs, with an apparent quantum efficiency of 7.48% at 450 nm. Electrochemiluminescence spectra, time-resolved photoluminescence spectra and electron spin resonance spectra further testify the enhanced charge transfer and the direct Z-scheme mechanism of the 0D/2D heterojunction. This work emphasizes the suitable band matching to adjust the exciton properties and charge transfer characteristics of QDs by constructing Z-scheme heterojunction for efficient utilization of visible light. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel Au/Ar-CN photocatalyst was designed for the photocatalytic CO 2 reduction. • Intramolecular modifications regulate the local π-electron distribution of CN. • The Schottky junctions modulate space charge transfer and provide CO 2 RR sites. • Au/Ar-CN performs high photocatalytic evolution CO rate of 32.03 μmol·g–1·h–1. Polymeric carbon nitride (CN) is one of the most prospective non-metallic catalysts at present, yet its photocatalytic activity is unsatisfactory mainly due to the poor intramolecular charge carrier separation efficiency originated form its special electronic structure. Herein, we demonstrate a synergistic strategy to improve the charge carriers transfer and separation efficiency of CN synchronously by extending the π-conjugated system via incorporation of O-containing aromatic ring in the CN skeleton (Ar-CN) and constructing a Schottky junction via decoration of Au nanoparticles (Au Nps). The introduced O-containing aromatic ring can create a local asymmetry, delocalize the π-conjugated system of CN, and thus promote the in-plane charge transport of CN, while the formed loading of Au Nps can further promote interlayer charge transfer efficiency of Ar-CN. The optimized 3 %Au/Ar-CN photocatalyst exhibits a high photocatalytic CO 2 activity with a CO yield of 32.03 μmol·g−1·h−1, which is higher than those of CN (2.38 μmol·g−1·h−1) and Ar-CN (6.42 μmol·g−1·h−1). This study provides a feasible co-modification strategy to enhance the charge transfer and photocatalytic activity of CN by extending the π-conjugation system and constructing Schottky junctions. [ABSTRACT FROM AUTHOR]

Novel visible-light-driven AgI/WO 3 nanocomposites were synthesized by a facile precipitation method. Multiple techniques were applied to investigate the structures, morphologies, optical and electronic properties and photocatalytic performance of as-prepared samples. The photocatalytic performance of the AgI/WO 3 nanocomposites was evaluated sufficiently by using colorless antibiotic agent tetracycline hydrochloride (TC). The optimum photocatalytic performance of TC photodegradation over 20%-AgI/WO 3 is as about 4.3 and 25 times high as that of pure AgI and WO 3 , respectively. The possible mechanism for the enhanced photocatalytic activity could be attributed to the formation of a redox-mediator-free direct Z-scheme system which causes the photogenerated electrons migrate from WO 3 to AgI, leading to effective charge separation of WO 3 . Furthermore, the stability and the possible mechanism of AgI/WO 3 nanocomposite photocatalysts for TC degradation are also elucidated. [ABSTRACT FROM AUTHOR]