Ozone-Assisted Cu-Based Catalysts for the Efficient Electro-Reforming Glycerol to Formic Acid.

Abstract

Glycerol electrooxidation reaction (GOR) to produce value-added chemicals, such as formic acid, could make more efficient use of abundant glycerol and meet future demand for formic acid as a fuel for direct or indirect formic acid fuel cells. Non-noble metal Cu-based catalysts have great potential in electro-reforming glycerol to formic acid. However, the high activity, selectivity and stability of Cu based catalysts in GOR cannot be achieved simultaneously. Here, we used ozone-assisted electrocatalyst to convert glycerol to formic acid under alkaline conditions, the onset potential was reduced by 60 mV, the Faraday efficiency (FE) reached 95 %. The catalyst has excellent stability within 300 h at the current density of 10 mA cm-2. The electron spin resonance proved that ozone produced superoxide anion during the GOR. In situ Raman spectroscopy, electrochemical studies showed that glycerol can be activated with ozone in GOR, and the C-C bond can be broken to reduce the polymerization of glycerol on the catalyst surface, so as to produce more formic acid at a lower voltage. Moreover, the removal of dissolved O3 from water can be up to 100 % after 30 minutes of GOR reaction at a solubility of 50 mg L-1 as measured by UV-VIS spectrophotometry.