Efficient electrooxidation of biomass-derived aldehydes over ultrathin NiV-layered double hydroxides films

Selective upgrading of CO bonds to afford carboxylic acid is significant for the petrochemical industry and biomass utilization. Here we declared the efficient electrooxidation of biomass-derived aldehydes family over NiV-layered double hydroxides (LDHs) thin films. Mechanistic studies confirmed the hydroxyl active intermediate (OH*) generated on the surface of NiV-LDHs films by employing electrochemical impedance spectroscopy and the electron paramagnetic resonance spectroscopy. By using advanced techniques, e.g., extended X-ray absorption fine structure and high-angle annular dark-field scanning transmission electron microscopy, NiV-LDHs films with 2.6 nm could expose larger specific surface area. Taking benzaldehyde as a model, high current density of 200 mA cm−2 at 1.8 V vs. RHE, 81.1% conversion, 77.6% yield of benzoic acid and 90.8% Faradaic efficiency were reached, which was superior to most of previous studies. Theoretical DFT analysis was well matched with experimental findings and documented that NiV-LDHs had high adsorption capacity for the aldehydes to suppress the side reaction, and the aldehydes were oxidized by the electrophilic hydroxyl radicals formed on NiV-LDHs. Our findings offer a universal strategy for the robust upgrading of diverse biomass-derived platform chemicals.