Pd Nanoparticles Coupled to WO_2.72 Nanorods for Enhanced Electrochemical Oxidation of Formic Acid

We synthesize a new type of hybrid Pd/WO_2.72 structure with 5 nm Pd nanoparticles (NPs) anchored on 50 × 5 nm WO_2.72 nanorods. The strong Pd/WO_2.72 coupling results in the lattice expansion of Pd from 0.23 to 0.27 nm and the decrease of Pd surface electron density. As a result, the Pd/WO_2.72 shows much enhanced catalysis toward electrochemical oxidation of formic acid in 0.1 M HClO₄; it has a mass activity of ∼1600 mA/mg_Pd in a broad potential range of 0.4-0.85 V (vs RHE) and shows no obvious activity loss after a 12 h chronoamperometry test at 0.4 V. Our work demonstrates an important strategy to enhance Pd NP catalyst efficiency for energy conversion reactions.