Electrocatalytic Oxidation of Formic Acid on Pt-Se Hollow Nanosphere Modified Glassy Carbon Electrodes

Platinum-selenium and platinum hollow nanospheres (denoted as (Pt-Se)(HN) and Pt-HN, respectively) with different coverages of Se (theta(Se))(theta(Se)=0.49, 0.39, 0.06, 0) were prepared using amorphous Se colloids as a sacrificial template. Sulfite was used to completely remove Se from the core-shell nanoparticles. The morphology and structure of the nanoparticles were characterized using various methods, which revealed a hollow structure with a very uniform size distribution and a porous structure on the shell. Assembly of Pt-Se hollow nanospheres ((Pt-Se)(HN)) on a glassy carbon (GC) electrode produced a (Pt-Se)(HN)/GC electrode. The electrocatalytic activity of the electrode for the oxidation of formic acid was compared with the Pt-HN/GC and commercial Pt/C/GC electrodes by cyclic voltammetry and chronoamperometry. The activity followed the order: (Pt-Se)(HN)/GC > Pt-HN/GC > Pt/C/GC. The electrooxidation of formic acid on (Pt-Se)(HN)/C, Pt-HN/C, and Pt/C catalysts follows different mechanisms: the former tends to directly oxidize formic acid to CO2 via weakly adsorbed intermediates, and the latter two via both weakly and strongly adsorbed intermediates. (Pt-Se)(HN) with a suitable selenium content showed optimal electrocatalytic activity for the oxidation of formic acid.