Ag-based photocatalytic heterostructures: Construction and photocatalytic energy conversion application

Global environment pollution and energy exhaustion are two main problems that threaten the existence of mankind. Construction of Ag-based heterostructures in photocatalytic application is one of the best promising means for resolving these environmental and energy issues. Ag materials possess with benign visible light absorption, great quantum efficiency, excellent electrical conductivity and photoelectrochemical activity. This critical review summarizes the construction and photocatalytic performance of Ag-based heterostructures (including semiconductor heterojunctions, Schottky junction and Z-scheme heterojunctions). The basic classification of photocatalyst and photocatalytic theory are briefly discussed for better understanding the construction principle of heterostructures. The foundational principles and recent progresses of these three kinds of heterojunction are also demonstrated subsequently. The roles of Ag-based semiconductors and metallic Ag in these heterostructures is an important parameter in design of these heterostructures. Among these heterostructures, Ag-based Z-scheme heterostructures presented with fast charge separation routes and more photostability in practical application have attracted interests in environment remedy and energy store. Therefore, the environmental and energy application, including environmental decontamination, photoelectrochemical water splitting, CO2 conversion and N-2 fixation, are elaborated in detail. Eventually, the challenges and perspectives of these Agbased heterostructures, even for Ag-based Z-scheme heterostructures, are proposed.