Enhanced Photocatalytic Activity and Selectivity for CO2 Reduction over a TiO2 Nanofibre Mat Using Ag and MgO as Bi‐Cocatalyst

Abstract The design and preparation of novel photocatalysts to enhance photocatalytic activity and selectivity for CO 2 reduction is highly important both theoretically and practically. Herein, we develop an electrospinning and wet‐impregnation method to obtain an Ag and MgO co‐modified TiO 2 nanofibrous mat. Ag nanoparticles (NPs) as electron traps can effectively separate electron−hole pairs and reduce their recombination in TiO 2 nanofibres due to the formation of Schottky barriers. Accumulation of photogenerated electrons in the Ag NPs can enhance the formation of CH 4 . The obtained Ag−MgO−TiO 2 composite mat exhibits extended visible light absorption owing to the surface plasmon resonance effect of the Ag NPs. Deposition of MgO NPs, as basic sites, could facilitate the adsorption of CO 2 molecules. The synergetic effects of Ag and MgO as a bi‐cocatalyst contribute to enhanced photocatalytic activity and CH 4 ‐selectivity for CO 2 reduction. Isotope ( 13 C) tracer experiments confirm that the products are produced from photocatalytic reduction of the CO 2 source instead of organic contaminants. This report highlights the importance of the synergistic effect of Ag and MgO NPs on enhancing the photocatalytic activity and selectivity of TiO 2 ‐based materials.