▎ 摘　　要

In this research, we synthesized a quaternary composite containing a graphene-based LaYAgO4-Graphene-TiO2 nanocomposite using a hydrothermal method. We examined all prepared samples by means of physical techniques, such as XRD, SEM-EDX, HRTEM, XPS, Raman, and DRS. We tested the photocatalytic activity of the ternary composite for CO2 reduction in a reactor using commercial carbonated water, and the target product was methanol (CH3OH), detected under UV and Vis light irradiation. The ternary nanocomposite, which contains three times a quaternary composite (LaYAgO4), exhibited high photocatalytic activity and improved a sum total of methanol of 12.27% after 48 h reaction time. In a heterogeneous system, the relevance between the GrapheneTiO(2) and LaYAgO4 components showed an excellent photoreduction efficiency. This heterojunction presented herein offers a promising route for the rational design of a new class of photocatalysts for various applications in environmental protection and solar-energy conversion.