Ethanol–water ambient precipitation of {111} facets exposed Ag3PO4 tetrahedra and its hybrid with graphene oxide for outstanding photoactivity and stability

Abstract

This study presents the combinative merits of facet effect and the graphene oxide (GO) hybrid of Ag₃PO₄ photocatalyst. First, Ag₃PO₄ tetrahedra with exposed {111} facets were controllably prepared via an ethanol–water ion exchange strategy at room temperature. The amount of ethanol was crucial to regulate the orientation growth of Ag₃PO₄ crystals along {111} planes through the balance of coordination and adsorption. The sample exhibited an enhanced visible-light photocatalytic efficiency of 3.3-fold for pollutant degradation as compared to that of Ag₃PO₄ particles due to the active facets. GO/Ag₃PO₄ hybrid was then constructed based on the electrostatic interaction between Ag⁺ enriched {111} facets and negatively charged GO sheets. The photocatalytic activity of the hybrid increased by 4.6-fold with admirable recyclability as compared to that of the bare Ag₃PO₄ tetrahedra. Systematical optical and photoelectrochemical characterizations revealed that the hybrid exhibits extended light absorption and significantly accelerated carrier transfer due to the coaction of unique charge mobility of GO, electronic effect of trace Ag and increased catalytic active sites. A possible migration mechanism of photoinduced carriers at the interface of GO/Ag₃PO₄ tetrahedron is proposed based on the above analyses, detected oxidative species and band positions of Ag₃PO₄ tetrahedra. This study provides new insight into the rational design of carbonaceous material-hybridized semiconductor photocatalysts with facet dependency.