Yuxiang Hua,Chengyao Hu,Muhammad Arif,Shen-ming Chen,Min Zhang,Xiaoheng Liu
The design of efficient and stable photocatalysts for the removal of heavy metals in the environment has become a research hotspot. Here, a composite photocatalyst with three-dimensional In 2 S 3 microspheres supported by WO 3 nanoparticles was synthesized for the photoreduction of Cr(VI) for the first time. The constructed composite catalyst has a direct Z-scheme electron transport mechanism without any precious metals (Au, Pt, and Ag), quantum dots (TiO 2 QDs) or carbon materials (Graphene) as electronic media. Constructing a direct Z-scheme WO 3 /In 2 S 3 photocatalyst can greatly retain the reduction and oxidation reaction sites on the surface of the heterojunction and accelerate the reduction reaction. Under visible light irradiation, it greatly promotes the photocatalytic reduction of Cr(VI), which is 67.7 times and 3.6 times the reduction rates of WO 3 and In 2 S 3 , respectively. The favorable photocatalytic performance of WO 3 /In 2 S 3 should be attributed to the effective interfacial contact between the semiconductors in the Z-scheme system, thereby realizing effective electron transfer and charge separation. In addition, the stability of WO 3 /In 2 S 3 was studied, and a possible mechanism in the photoreduction process of Cr(VI) was proposed.
Constructing heterostructures is an effective strategy to improve the performance of semiconductor metal oxide . The heterostructure exhibits strong interaction between tightly packed interfaces, showing better performance than a single structure. Therefore, indium sulfide (In 2 S 3 )/tungsten oxide (WO 3 ) composites were synthesized with heterojunction by a simple hydrothermal method to enhance the gas sensing performance of WO 3 . The WO 3 and In 2 S 3 exist in the form of nanoparticles . Then the gas sensing test of the material was carried out, by exploring the performance of WO 3 based on doping different amounts of In 2 S 3 , the response of WO 3 based on 3 wt% In 2 S 3 to 10 parts per million (ppm) nitrogen dioxide (NO 2 ) is 170.1 at the optimum operating temperature of 170 °C. Compared with pure WO 3 , the response is enhanced by seven times. Besides, the detection limit of the sample is low. The minimum detection concentration of NO 2 can reach 20 parts per billion (ppb). The reason for the improved performance can be attributed to the wider electron depletion layer or hole accumulation layer formed by the heterojunction for electron transfer . Finally, a convenient wearable NO 2 Real-time Detection System is designed to detect different concentrations of NO 2 in the factory, which provides an effective alarm mean for the excessive emission of industrial waste gas in the factory environment.
CO2photoreduction technology offers significant potential for addressing energy and environmental challenges, though its practical application is hindered by insufficient photo-absorption and rapid carrier recombination. Herein, we constructed the WO3/In2S3S-scheme heterojunction through hydrothermal assembly of two-dimensional WO3nanosheets and scale-like In2S3nanoflakes. Systematic characterization via XRD, XPS, SEM, and TEM verified the successful preparation of hierarchical nanostructures with optimized interfacial contact in the WO3/In2S3composites. UV-Vis DRS analysis showed that the photo-absorption range of the catalyst was significantly widened. Photoelectrochemical investigations (EIS, TPR, PL, and LSV) revealed enhanced carrier separation efficiency and reduced recombination kinetics in the heterojunction system. The optimized WO3/In2S3(WI-60) catalyst had a CO evolution efficiency of 55.14 μmol·g−1under the UV-Vis light, representing a 3.9-fold enhancement over the pure In2S3(14.08 μmol·g−1). Mechanistic studies through the XPS and band-structure analysis confirmed the establishment of an S-scheme carrier’ transfer pathway, which simultaneously preserved strong redox potentials and promoted the separation process of carriers. This research provides a validated strategy for developing efficient S-scheme photocatalytic systems for solar fuel generation.
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