Highly stable LaCoO3 perovskite supported g-C3N4 nanotextures with proficient charges migration for visible light CO2 photoreduction to CO and CH4

Abstract

Z-scheme LaCoO3/g-C3N4 heterojunction, synthesized via a facile one-step wet impregnation process, has been investigated for photoinduced CO2 reduction to CO and CH4. The LaCoO3 was uniformly dispersed with g-C3N4 nanotexture to construct heterojunction with proficient electron-hole separation due to good interfacial interaction. The photocatalytic CO2 reduction reveals highest CO evolution over 15% LaCoO3 loaded g-C3N4 with yield rate 135.2 μmol g−1h−1, which is 1.2 and 1.18 folds-higher than using pristine LaCoO3 and g-C3N4 samples, respectively. Similarly, in comparison to LaCoO3 and g-C3N4, using LaCoO3/g-C3N4, CH4 evolution of 1.7 and 1.59 folds higher was achieved. This significantly enhanced productivity toward CO and CH4 was evidently due to good interface interaction with higher light absorption and fascinating separation of charge carrier. Among the operating parameters, highest photoactivity for CO and CH4 production was achieved at lower catalyst loading, which confirms higher light utilization to promote quantum yield of the products. This further confirms that mass transfer and catalyst exposed to light irradiations are the determinable factors to promote efficiency. Furthermore, Z-scheme LaCoO3/g-C3N4 composite exhibits excellent stability in consecutive three cycles. This research provides pathways to construct composite photocatalyst with high-performance and stability, thus would also be useful for other solar energy applications.