Complete Oxidation of Formaldehyde at Room Temperature Using TiO₂ Supported Metallic Pd Nanoparticles

A series of reduced and oxidized Pd/TiO2 catalysts were prepared and used for catalytic oxidation of formaldehyde (HCHO) at room temperature. The reduced catalysts were much more active than the oxidized ones. Nearly 100% HCHO conversion was achieved over the former while it was less than 18% over the latter. Sodium borohydride (NaBH4) reduced Pd/TiO2 catalysts exhibited very high turnover frequencies of HCHO oxidation and kept highly active in the presence of chloride. Strong metal−support interaction, well-dispersed and negatively charged metallic Pd nanoparticles, and rich chemisorbed oxygen are probably responsible for the high catalytic activities over the former. Metallic Pd nanoparticles with a strong capacity for oxygen activation should be the active sites for catalytic oxidation of HCHO.