Online FTIR and Mass Spectrometry Study of Direct Methyl Formate Electro-oxidation for Fuel-Cells Application

We examined the electro-oxidation of methyl formate on a ternary nanocatalyst supported on a multiwall carbon nanotube (Pt3Pd3Sn2/MWCNT). Compared to PtRu/C, this nanocatalyst exhibited a 2.5 times higher peak oxidation current (482 mA mg–1 at 1.00 V vs RHE) for methyl formate oxidation. The oxidation mechanism was studied by online electrochemical Fourier-transform infrared spectrometry and online mass spectrometry. The online spectroscopic studies illustrate that CO2 from formate oxidation and methanol is formed electrochemically in the first step. In the low potential region (<0.60 V), CO2 is mainly produced from the oxidation of the formate part, while at high potentials (>0.60 V) it is formed from the methanolic part of methyl formate. Comparison of methyl formate oxidation behavior with its constituent molecules i.e., methanol and formic acid confirms a fully electrochemical methyl formate path besides the widely proposed large-scale chemical hydrolysis of methyl formate within the time scale of the measurement. A comparative study of different catalyst support materials (Vulcan XC72, Black Pearl Carbon 2000, and MWCNT) in aqueous electrolyte and fuel cells revealed superior activity of the MWCNT-supported nanocatalyst owing to its one-dimensional structure, which facilitates ease of accessibility to the fuel.