A dual-cocatalyst-loaded Au/BiOI/MnOx system for enhanced photocatalytic greenhouse gas conversion into solar fuels

Abstract

Photocatalysis is a green and economical method to convert greenhouse gases such as carbon dioxide (CO₂) for environmental remediation and solar fuel generation. In a semiconductor photocatalyst system, cocatalysts play a very important role. They are not only redox-active sites but also can be used to improve the separation efficiency of photo-induced carriers. In this work, a dual-cocatalyst-loaded Au/BiOI/MnO_x photocatalyst was prepared to enhance the photocatalytic reduction activity for the conversion of greenhouse gases (CO₂) into solar fuels. The as-prepared BiOI, Au/BiOI, MnO_x/BiOI and Au/BiOI/MnO_x were characterized by using X-ray diffraction patterns (XRD), the Brunauer–Emmett–Teller (BET) method, transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic reduction results showed that Au/BiOI/MnO_x had higher activity than pure BiOI, MnO_x–BiOI, Au–BiOI and other BiOI-based photocatalysts for solar fuel generation. Photocurrent and electrochemical impedance (EIS) spectroscopy revealed that the efficient photo-induced carrier separation efficiency of Au/BiOI/MnO_x induced the high photocatalytic activity.