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Exploring high efficiency S‐scheme heterojunction photocatalysts with strong redox ability for removing volatile organic compounds from the air is of great interest and importance. However, how to predict and regulate the transport of photogenerated carriers in heterojunctions is a great challenge. Here, density functional theory calculations were first used to successfully predict the formation of a CdS quantum dots/InVO4 atomic‐layer (110)/(110) facet S‐scheme heterojunction. Subsequently, a CdS quantum dots/InVO4 atomic‐layer was synthesized by in‐situ loading of CdS quantum dots with (110) facets onto the (110) facets of InVO4 atomic‐layer. As a result of the deliberately constructed built‐in electric field between the adjoining facets, we obtain a remarkably enhanced photocatalytic degradation rate for ethylene. This rate is 13.8 times that of pure CdS and 13.2 times that of pure InVO4. In‐situ irradiated X‐ray photoelectron spectroscopy, photoluminescence and time‐resolved photoluminescence measurements were carried out. These experiments validate that the built‐in electric field enhanced the dissociation of photoexcited excitons and the separation of free charge carriers, and results in the formation of S‐scheme charge transfer pathways. The reaction mechanism of the photocatalytic C2H4 oxidation is investigated by in‐situ electron paramagnetic resonance. This work provides a mechanistic insight into the construction and optimization of semiconductor heterojunction photocatalysts for application to environmental remediation. [ABSTRACT FROM AUTHOR]

Photocatalytic oxidation of ethylene continues to be a challenge at the frontier of chemistry. In a previous report, a simple Ag3PO4 semiconductor material was shown to have strong photooxidative properties and efficiently oxidised water and decomposed organics in aqueous solution under visible-light illumination. Herein, its effects on the photo-oxidation of gaseous C2H4 were investigated by fabricating graphitic C3N4-Ag3PO4 composite semiconductors with direct Z-scheme configuration. It was found that both the ethylene photo-oxidative activity and the stability of Ag3PO4 are considerably improved by fabrication of Z-scheme composites. Moreover, stable C2H4 photo-oxidation activity could be obtained by treating the composite at 450 °C for 3 h after long-term operation. From the point of view of environmental pollutant cleanup, the present technique avoids the side reaction of oxidising water and will be valuable for further investigations on both Ag3PO4 and CH degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoO was first used as C 2 H 4 degradation photocatalyst in this study. • A 0D/2D CoO QDs/Bi 2 MoO 6 monolayer S-scheme heterojunction is built. • This photocatalyst shows outstanding visible light activities for C 2 H 4 degradation. • The S-scheme heterojunction enhances the stability of CoO in photocatalytic reaction. • The S-scheme heterojunction could apply in fruit and vegetable preservation. As a plant hormone, C 2 H 4 causes significant economic losses during the storage and transportation of fruits and vegetables. How to efficiently photocatalytic oxidation of atmospheric C 2 H 4 using sun-light remains a significant challenge at the frontiers of chemistry. Inspired by natural photosynthesis of plant, here, we design a novel S-scheme heterojunction for highly efficient photocatalytic C 2 H 4 degradation. We first conducted density functional theory (DFT) calculations to predict an S-scheme heterojunction can be formed between CoO and Bi 2 MoO 6 , and then fabricated a novel CoO Quantum dots (QDs)/Bi 2 MoO 6 monolayer S-scheme heterojunction by using a practical hydrothermal approach to in-situ deposit CoO QDs on a Bi 2 MoO 6 monolayer. Furthermore, the UV–Vis DRS, UPS, in-situ XPS and electron spin resonance (ESR) characterization of DMPO-•O 2 – signals and DMPO-•OH signals evidence that the transfer pathway of space charge in photocatalytic degradation of ethylene accords with the S-scheme. Moreover, due to the unique structural design, CoO QDs and Bi 2 MoO 6 monolayer form an S-scheme heterojunction, and the intimate contact that enables efficient charge transfer and sufficient redox ability simultaneously, the CoO QDs/Bi 2 MoO 6 monolayer catalyst achieves a remarkable ethylene photocatalytic-degradation rate of 3.27 × 10−2∙min−1, 19.2 times higher than CoO and 22.5 times higher than Bi 2 MoO 6. This work provides novel insights for designing efficient S-scheme photocatalysts for C 2 H 4 degradation. [ABSTRACT FROM AUTHOR]

Achieving efficient photocatalytic degradation of atmospheric volatile organic compounds (VOCs) under sun-light is still a significant challenge for environmental protection. The S-scheme heterojunction with its unique charge migration route, high charge separation rate and strong redox ability, has great potential. However, how to regulate interfacial charge transfer of the S-scheme heterojunction is of significant importance. Here, density functional theory (DFT) calculations were first conducted and predicted that an S-scheme heterojunction could be formed in the CdS quantum dots/Bi 2 MoO 6 monolayer system. Subsequently, this novel heterojunction is constructed by in-situ hydrothermal synthesis of CdS quantum dots on monolayer Bi 2 MoO 6. Under visible-light, this novel S-scheme system gives a high-efficiency photocatalytic degradation rate (6.04 × 10−2 min−1) towards C 2 H 4 , which is 30.3 times higher than that of pure CdS (1.99 × 10−3 min−1) and 41.7 times higher than pure Bi 2 MoO 6 (1.45 × 10−3 min−1). Strong evidence for the S-scheme charge transfer path is provided by in-situ XPS, PL, TRPL and EPR. [Display omitted] • A novel S-scheme CdS QDs/Bi 2 MoO 6 monolayer photocatalyst was synthesized. • This S-scheme heterojunction shows excellent activities for C 2 H 4 photodegradation. • The reaction mechanism of C 2 H 4 photooxidation was comprehensively investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Designed and fabricated a CdS QDs/Bi 2 WO 6 monolayer S-scheme heterojunction. • Bi-S bonds deliberately introduced at the interface to regulate the charge transfer. • S-scheme heterojunction show excellent photoactivities for C 2 H 4 oxidation. The S-scheme heterojunction with unique photogenerated electrons and holes migration pathway, excellent separation efficiency of photogenerated carrier and high redox potential, has great potential in this field of photocatalytic oxidation of atmospheric C 2 H 4. However, optimising the transfer of photogenerated charge at the S-scheme heterostructure interface continues to a major challenge. Here, density functional theory (DFT) calculations were first conducted to predict an S-scheme heterojunction can be formed in the CdS quantum dots (QDs)/Bi 2 WO 6 monolayer system, and then CdS QDs/Bi 2 WO 6 monolayer S-scheme heterojunction were constructed by in-situ hydrothermal synthesis of CdS QDs onto Bi 2 WO 6 monolayer. Bi-S bonds are deliberately introduced at the interface to maximise the photogenerated charge transfer. As expected, the substantial enhancement of the photocatalytic degradation of ethylene and the photostabilization of CdS is demonstrated. The S-scheme band alignment and the connected Bi-S coordination introduced at the junction interface allow highly efficient charge separation and an effective interfacial charge migration path. This research provides a basis for understanding the design of materials for the removal of hydrocarbons in air and environmental pollutant remediation, and improving the stability of sulfide and other photocatalysts to photocorrosion. [ABSTRACT FROM AUTHOR]