Synergistic effect of Ag decorated in-liquid plasma treated titanium dioxide catalyst for efficient electrocatalytic CO reduction application.

Recently, the conversion of carbon dioxide (CO) into a useful resource and its byproducts by electrocatalytic reduction has been studied. It is well known that CO can be selectively reduced by gold, lead, etc. supported on conductive carbon. However, the high pH in the vicinity of the electrode raises concerns about the catalyst and catalyst support degradation. Therefore, we considered that using chemically stable TiO (titanium dioxide) powder as an alternative to carbon. Surface treatment using in-liquid plasma was used to improve the electrochemical properties of TiO. TiO maintained its particle shape and crystalline structure after in-liquid plasma treatment. Electrochemical properties were evaluated and the disappearance of Ti and Ti redox peaks derived from TiO and a decrease in hydrogen overvoltage were observed. The hydrogen overvoltage relationship suggested that tungsten coating or doping on a portion of the reduced TiO surface. Electrocatalytic CO reduction using the silver nanoparticle-supported in-liquid plasma treated TiO showed increased hydrogen production. In electrocatalytic CO reduction, the ratio of hydrogen to carbon monoxide gas is important. Therefore, in-liquid plasma treated TiO is useful for the electrocatalytic CO reduction application.