Z-scheme Ag-NPs-embedded LaCoO3 dispersed pCN heterojunction with higher kinetic rate for stimulating photocatalytic solar H-2 production

Abstract

Well-designed LaCoO3 perovskite anchored pCN Z-scheme heterojunction embedded with Ag NPs was fabricated for photocatalytic H2 evolution under visible irradiation. The pure LaCoO3 phase was obtained having narrow band gap through the combination of coprecipitation and hydrothermal method. The controlled interface heterojunction was produced for the proficient charge's mobility with the capability of Ag to act as an electron sink. The Ag-LaCoO3/pCN nanocomposite generated H2 yield of 3160 µmol g-1, a 5.5 and 7-folds improved compared to pCN and LaCoO3 samples, respectively. Among the sacrificial agent, TEOA yielded boosted H2 production compared to methanol, linked to strong binding of amine containing pCN with TEOA. Ag-LaCoO3/pCN nanocomposite depicted an excellent stability and reusability over 4 consecutive cycles. Overall, the improved photoactivity was associated with Z-scheme formation of LaCoO3/pCN supported with Ag-NPs, leading to improved absorption of visible light, effective charge separation with more reaction sites. Kinetic model based on the Langmuir-Hinshelwood model was developed for the determining rate of reaction. The model results were fitting well with the experimental data, attributing adsorption process is the rate limiting step and controlled overall reaction kinetics. In conclusion, this study contributes to the development of efficient photo-technology for H2 production towards sustainable solar fuels.