A Voltage Bias Effect on Catalytic Activity of Electrically Continuous Pt/TiO₂ Nanocomposites

Abstract

Recently, efforts to optimize catalytic performance have included the utilization of catalytic nanoparticles with careful control over their shape and size, chemical composition, surface functionalization, and structural architecture. Here, we report direct measurements detailing the impact of applied external bias on the exothermic catalytic formation of water for a Pt/TiO 2 nanocomposite under exposure to gaseous oxyhydrogen environments. As external voltages of opposite polarity are applied to the system, the surface temperature kinetics, total pressure kinetics within the analytical chamber, and water turnover frequency transition in a reproducible manner between two well-defined states, resulting in (1) decreased catalytic activity, (2) decreased initial molecular adsorption onto the Pt catalyst, and (3) lower rates of water production under negative voltage. These findings pave the road toward the realization of a catalytic switch that can be activated by applying a voltage to Schottky barrier systems to enhance or mitigate catalytic surface reactions.