Electrochemical Reduction of Carbon Dioxide at TiO/Au Nanocomposites.

Herein, we report on the facile synthesis of nanocomposite consisting of TiO and Au nanoparticles (NPs) via a tailored galvanic replacement reaction (GRR). The electrocatalytic activity of the synthesized TiO/Au nanocomposites for CO reduction was investigated in an aqueous solution using various electrochemical methods. Our results demonstrated that the TiO/Au nanocomposites formed through the GRR process exhibited improved catalytic activities for CO 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 were the gas products, whereas HCOO, CHCOO, CHOH, and CHCHOH were the liquid products from the CO reduction at different cathodic potentials. This remarkable change was further studied using the density functional theory (DFT) calculations, showing that the TiO/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/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 to value-added products.