Xiaoya Gao,Guangbei Tang,Wen Peng,Qian Guo,Yongming Luo
Phosphate modification is a general strategy for improving the photocatalytic activities of semiconductors. Ion exchange can be occurred during the phosphate modification process. This would give a surprise for a new phase formed on the surface of the parent photocatalyst. More importantly, this is conductive to form close contact and continuous interface favoring the charge transfer between two phases. Here, a novel BiOCl-OV-BiPO 4 photocatalyst was fabricated using a facile in situ phosphate modification method. BiOCl-OV-BiPO 4 displayed a maximum carbamazepine (CBZ) degradation efficiency of 81.70% after 30 min Xe lamp irradiation, with a reaction kinetics rate constant ( k ) of 5.75 times higher than ordinary BiOCl samples. Oxygen vacancy (OV) is important for the construction of Z-scheme BiOCl-OV-BiPO 4 : OV benefits the generation of BiPO 4 on the surface of BiOCl; furthermore, OV acting as electron mediator, promotes the separation of photogenerated charge carriers between BiOCl and BiPO 4. Based on the results from PL tests, photocurrent density, EIS Nyquist plots, and cyclic voltammetry, it can be demonstrated that Z-scheme structure of BiOCl-OV-BiPO 4 not only increases the photogenerated electrons-holes separation rate but also retains their strong redox ability. This significantly facilitates the production of superoxide radical (O 2 − ) and holes ( h + ), which dominates the CBZ photodegradation. This work provides a new sight for the fabrication of Z-scheme photocatalysts to improve the photocatalytic performance.
Xue Ye,Yangzhou Xu,Peipei Zhang,Dongwang Zhu,Zhicheng Chen,Yudong Xia,Fulin Yang,Xinhua Gao,Jie Li
CO 2 hydrogenation to methanol is one of the most promising pathways for emission reduction. Unlike traditional synthesis gas (CO + H 2 ) to methanol, a major challenge is that the activation of inert CO 2 at high temperature will induce the reverse water-gas shift (RWGS) reaction to generate CO, thereby reducing the methanol yield. In this research, a novel catalyst Cu 7 Zn 3 Cr 0.3 was synthesized by the carbon microsphere-assisted sol-gel method, which remarkably achieved a maximum methanol space-time yield of 345.1 g kg cat −1 h −1 under mild conditions (200 °C, 3.0 MPa, and 21600 mL g cat −1 h −1 ). Characterizations combined with theoretical simulations show that Cr doping can affect the crystal structure of ZnO, resulting in the formation of more oxygen vacancies (O V s), and induce Cu to form a stable Cu 0 -O V -Cu + active center at the interface. This active structure efficiently enhances the adsorption and activation of CO 2 , while changing the reaction path to inhibit the production of CO. The results indicate that there is a clear linear relationship between the Cu + and O V s concentration and methanol yield, which could provide experimental references for the development of high-performance catalysts for CO 2 methanol production.
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