Novel Z-scheme composite Ag2CrO4/NG/polyimide as high performance nano catalyst for photoreduction of CO2: design, fabrication, characterization and mechanism

Abstract

The evolution of new Z-scheme composites aids to solve the increasing energy demand via artificial photosynthesis. This research introduced novel Z-scheme nanocomposite, Ag2CrO4/nitrogen-doped graphene /Polyimide (Ag2CrO4/NG/PI), and its photocatalytic activity in CO2 reduction under simulated sunlight irradiation. The nanocomposite was prepared with ultrasound-assisted in-situ deposition of different amounts of Ag2CrO4-NPs on NG/ PI and completely characterized using various techniques such as AFM, FE-SEM, XPS, XRD, FT-IR, DRS and PL which confirmed the presence of Ag2CrO4, NG and PI in the composite structure. The photocatalytic investigations showed a significant promotion for light absorption ability of Ag2CrO4 on NG and PI. The high performance photocatalytic activity of Ag2CrO4/NG/PI can be interpreted by the gap of EHPs in the photocatalyst as a Z-scheme due to the construction of hetero-linkage structure between Ag2CrO4 and PI. Meanwhile, the presence of the pyridinic N as an unique selective site toward CO generation, can reduce the free energy barrier for the potential-limiting step to compose important intermediates which lead to high-efficiency photocatalyst activity. The optimal Ag2CrO4/NG/PI (25AN) photocatalyst presented a CO2 photoreduction rate of 352.1 μmol h−1·gcat −1, which was higher than previously reported works under similar condition. This investigation introduces a novel photocatalyst nanocomposite of the, Ag2CrO4/NG/PI, in concurrent natural resources conservation and green productivity.