Photoinduced deposition of palladium nanoparticles on TiO2 nanotube electrode and investigation of its capability for formaldehyde oxidation

Highly ordered palladium nanoparticle modified TiO2 nanotube electrode (Pd/TiO2NT/Ti) was prepared by electrochemical anodization of a Ti sheet, followed by photocatalytic reduction process in palladium chloride solution. The prepared electrodes were characterized by SEM, EDX, and EIS techniques. The electrocatalytic oxidation of formaldehyde at the surface of Pd/TiO2NT/Ti was studied by cyclic voltammetry and chronoamperometry methods. Oxidation of formaldehyde was well evidenced by appearance of two well defined anodic peaks in the forward and backward scans during CV experiments. Effects of some parameters including formaldehyde concentration, scan rate, and upper potential limit on the electrooxidation performance of electrode were investigated. In comparison with some of the previously reported electrodes, the Pd/Ti/TiO2NTs anode exhibited superior performance for electrooxidation of formaldehyde with a very low overpotential and high current density. This electrode showed a good stability during experiments and after storage for a long time in dry condition.