Yanze Wang,Zhenyu Liu,Wenxuan Wang,Junxiao Tang,Rongjie Wang,Jingjing Xie,Zhengyi Fu
Accelerating charge transport and avoiding recombination are promising strategies for establishing highly efficient artificial photosystems. Herein, an S-scheme heterostructure consisting of Zn x Cd 1− x S and TiO 2 is fabricated via the in situ crystal growth method. The refined structure significantly enhances the transport of photogenerated charges, thereby improving photocatalytic hydrogen production efficiency. The optimized TiO 2 −Zn x Cd 1− x S composite, incorporating 60% TiO 2 with Zn 0.4 Cd 0.6 S, exhibits a robust H 2 evolution rate of 50.96 mmol g −1 h −1 with continuous release of H 2 bubbles. It is worth noting that the hydrogen production rate in seawater is as high as 26.22 mmol g −1 h −1 . The strong interfacial interaction and staggered band alignment between TiO 2 and Zn x Cd 1− x S result in the formation of a built-in electric field and high-content oxygen vacancies, which can drive the directional migration of photoelectrons with high redox ability and high speed. The designed photocatalyst with S-scheme and rich Oxygen vacancies at the interface provides a new approach for fabricating high-efficiency photocatalysts.
Lifang Chen,Haiyang Zheng,Aimin Li,Xin Qiu,Lian Wang
The photocatalytic reduction of nitrate has received considerable attention due to its high efficiency and environmentally friendly nature. The excessive addition of hole scavengers is the most commonly used method to increase the nitrate reduction efficiency. However, achieving high selectivity in the photocatalytic reduction of nitrate to N 2 with low concentration of hole scavengers remains challenging. In this study, the SrFe x Ti 1−x O 3 /TiO 2 S-scheme heterojunction photocatalysts with many Lewis acidic adsorption sites have been developed. The experimental results demonstrated that the incorporation of 6% Fe into SrFe 0.06 Ti 0.94 O 3 /TiO 2 (SFTO6) resulted in the nitrate conversion rate of 97.68% and the N 2 selectivity reached 96.35% with 25 mmol/L formic acid . Moreover, it also exhibited excellent stability and recycle ability. After 5 cycles, SFTO6 still exhibited a stable photocatalytic denitration efficiency of 92.94%, highlighting its potential for practical application. Through comprehensive mechanistic investigations, enhancing direct reduction process is considered the key to its high reduction efficiency with low formic acid . And the Lewis acidic adsorption sites enhance N 2 selectivity by enriching NO x − on the surface of the material. Overall, this study provides a novel approach for achieving efficient photocatalytic reduction of nitrate to N 2 under conditions with low concentration of hole scavengers.
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