Highly selective catalytic pathway utilizing metal oxide nanoparticles to produce formic acid through methanol oxidation

Abstract

An emerging alternative energy source is formic acid, which has low toxicity and high hydrogen-carrying capacity. Metal-containing nanoparticles are very attractive for many applications, allowing large-scale and environmentally friendly production. This study proposes liquid-state synthesis for clean and facile formic acid production via methanol oxidation over metal oxide nanoparticles. MoO₃, Fe₂O₃, TiO₂ and V₂O₅ nanocatalysts were prepared through sol–gel, solvothermal, reflux condensation and ball milling techniques, respectively, and their efficacy in formic acid production via methanol oxidation was assessed. The synthesized nanoparticles were further characterized through scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The performance of laboratory-prepared nanoscale metal oxide catalysts for formic acid production was evaluated through batch reactions under ambient temperature and pressure conditions to enhance energy efficiency and maximize conversion. Formic acid was quantitatively analyzed using high-performance liquid chromatography (HPLC). Results revealed that the nanocatalysts considerably promoted the generation of formic acid, especially MoO₃, which provided a 91% product acid yield, which was the greatest among the other nanocatalysts under the employed reaction conditions.