Insights on the electrooxidation of formaldehyde over bimetallic Co2V2O7 nanorod and its implication towards water electrolysis

Abstract

Potential electrocatalytic system based on monoclinic Co₂V₂O₇ nanorods (Co₂V₂O₇ NRs) is proposed to realize formaldehyde (H₂CO) assisted green hydrogen production at ultra-low overpotential in an alkaline electrolyte. The mechanistic knowledge of H₂CO assisted hydrogen production over Co₂V₂O₇ NR surface is gained by the combination of experimental and density functional theory. The computational studies confirm that the Co₂V₂O₇ surface exhibit highest adsorption energy of −0.185 eV towards H₂CO oxidation compared to V₂O₅ (−0.144 eV) and Co₃O₄ (−0.108 eV). The Co₂V₂O₇ NRs renders kinetically more favorable surface for selective oxidation of H₂CO (SOF) compared to its counterparts Co₃O₄ and V₂O₅. The SOF over Co₂V₂O₇ NR surface results in green hydrogen at ultra-low overpotential and high-valued low-cost chemical formic acid. The Co₂V₂O₇ NRs exhibit an ultra-low onset potential of 1.26 V vs RHE towards FOR in three electrode configuration while Co₂V₂O₇ NRs || Co₂V₂O₇ cell needs a low cell potential of only 1.48 V at 10 mA cm⁻² in H₂CO assisted hydrogen production. The proposed research opens a new way to treat H₂CO contaminated water with simultaneous production of green hydrogen.