Online FTIR\nand Mass Spectrometry Study of Direct\nMethyl Formate Electro-oxidation for Fuel-Cells Application

We examined the electro-oxidation of methyl formate on\na ternary\nnanocatalyst supported on a multiwall carbon nanotube (Pt<sub>3</sub>Pd<sub>3</sub>Sn<sub>2</sub>/MWCNT). Compared to PtRu/C, this nanocatalyst\nexhibited a 2.5 times higher peak oxidation current (482 mA mg<sup>–1</sup> at 1.00 V vs RHE) for methyl formate oxidation. The\noxidation mechanism was studied by online electrochemical Fourier-transform\ninfrared spectrometry and online mass spectrometry. The online spectroscopic\nstudies illustrate that CO<sub>2</sub> from formate oxidation and\nmethanol is formed electrochemically in the first step. In the low\npotential region (<0.60 V), CO<sub>2</sub> is mainly produced from\nthe oxidation of the formate part, while at high potentials (>0.60\nV) it is formed from the methanolic part of methyl formate. Comparison\nof methyl formate oxidation behavior with its constituent molecules\ni.e., methanol and formic acid confirms a fully electrochemical methyl\nformate path besides the widely proposed large-scale chemical hydrolysis\nof methyl formate within the time scale of the measurement. A comparative\nstudy of different catalyst support materials (Vulcan XC72, Black\nPearl Carbon 2000, and MWCNT) in aqueous electrolyte and fuel cells\nrevealed superior activity of the MWCNT-supported nanocatalyst owing\nto its one-dimensional structure, which facilitates ease of accessibility\nto the fuel.