g‑C3N4 recombining with recovered TiO2 from Waste SCR Catalyst for photocatalytic CO2 reduction

Abstract

Abstract Purpose Photocatalytic reduction of CO2 to CO is an ideal way to provide renewable energy and mitigate global warming. The g‑C3N4 recombining with recovered TiO2 from waste SCR catalyst to prepare g-C3N4/TiO2 heterostructures photocatalyst showed good photocatalytic performance in photocatalytic CO2 reduction, which can not only realize cost-efficiency but also recycle waste SCR catalyst is of great significance. Methods TiO2 recovered from waste SCR catalysts through carbonate leaching. The g-C3N4/TiO2 heterojunction photocatalyst was prepared by calcination method. The photocatalytic activity of the g-C3N4/TiO2 photocatalysts was evaluated in the photocatalytic reduction of CO2. Results The recovered TiO2 still remains the crystal structure of the standard anatase TiO2 phase by XRD. The tremella structure g-C3N4/TiO2 heterojunction photocatalys with larger specific surface area and smaller band gap showed good photocatalytic activity. The specific surface area of CNT3:1 sample is 109 m2g− 1, the band gap is 2.40 eV, and the average CO yield reaches 1.2488 µmol·g− 1h − 1. Conclusion Used the TiO2 carrier from waste SCR catalysts to synthesize a series of g-C3N4/R-TiO2 photocatalyst materials for efficient CO2 reduction. The g-C3N4 recombining with recovered TiO2 from waste SCR catalyst extends the visible range and reduces the rate of photogenerated carrier recombination in the g-C3N4/R-TiO2 composite photocatalyst. The average CO production rate reached 1.2488 µmol·g–1h−1 of CNT3:1 sample with band gap 2.40 eV and surface area (SBET) of 109 m2g− 1.