Enhanced photocatalytic activity and selectivity for CO₂ reduction over a TiO₂ nanofibre mat using Ag and MgO as bi‐cocatalyst

The design and preparation of novel photocatalysts to enhance photocatalytic activity and selectivity for CO₂ 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 TiO₂ nanofibrous mat. Ag nanoparticles (NPs) as electron traps can effectively separate electron−hole pairs and reduce their recombination in TiO₂ nanofibres due to the formation of Schottky barriers. Accumulation of photogenerated electrons in the Ag NPs can enhance the formation of CH₄. The obtained Ag−MgO−TiO₂ 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 CO₂ molecules. The synergetic effects of Ag and MgO as a bi‐cocatalyst contribute to enhanced photocatalytic activity and CH₄‐selectivity for CO₂ reduction. Isotope (¹³C) tracer experiments confirm that the products are produced from photocatalytic reduction of the CO₂ 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 TiO₂‐based materials. Copyright © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.