Electrochemical Reduction of Carbon Dioxide at TiO 2 /Au Nanocomposites.

Herein, we report on the facile synthesis of nanocomposite consisting of TiO 2 and Au nanoparticles (NPs) via a tailored galvanic replacement reaction (GRR). The electrocatalytic activity of the synthesized TiO 2 /Au nanocomposites for CO 2 reduction was investigated in an aqueous solution using various electrochemical methods. Our results demonstrated that the TiO 2 /Au nanocomposites formed through the GRR process exhibited improved catalytic activities for CO 2 reduction, while generating more hydrocarbon molecules than the typical formation of CO in contrast to polycrystalline Au. GC analysis and NMR spectroscopy revealed that CO and CH 4 were the gas products, whereas HCOO - , CH 3 COO - , CH 3 OH, and CH 3 CH 2 OH were the liquid products from the CO 2 reduction at different cathodic potentials. This remarkable change was further studied using the density functional theory (DFT) calculations, showing that the TiO 2 /Au nanocomposites may increase the binding energy of the formed · CO intermediate and reduce the free energy compared to Au, thus favoring the downstream generation of multicarbon products. The TiO 2 /Au nanocomposites have high catalytic activity and excellent stability and are easy to fabricate, indicating that the developed catalyst has potential application in the electrochemical reduction of CO 2 to value-added products.