Selective Electrooxidation of Glycerol to Formic Acid over Carbon Supported Ni<sub>1–<i>x</i></sub>M<sub><i>x</i></sub>(M = Bi, Pd, and Au) Nanocatalysts and Coelectrolysis of CO<sub>2</sub>
Mohamed S.E. Houache, Reza Safari, Uzoma O. Nwabara, Thibault Rafaïdeen, Gianluigi A. Botton, Paul J. A. Kenis, Stéve Baranton, Christophe Coutanceau, Elena A. Baranova
Abstract
The composition effect of carbon supported NixM1–x (M = Bi, Pd, and Au) nanomaterials toward glycerol electrooxidation (GEOR) was evaluated in alkaline media. Ni-rich catalysts with different atomic ratios (M atomic ratio ≤20%) were synthesized by the heatless coreduction method and characterized by various physicochemical and electrochemical techniques. All structures of the NixM1–x/C catalysts were composed of a rich phase of Ni(OH)2, as evidenced by TDA-TGA and XPS. Among the different nanomaterials, the Ni0.9Au0.1/C catalyst provided the lowest onset potential (+0.12 V vs Hg/HgO) and the highest peak current density. In situ infrared spectroscopy experiments combined with electrochemical measurements exhibited the formation of formate for all catalysts, thus indicating the breakage of C–C bonds of glycerol. GEOR led to 100% selectivity for formate after 1 h electrolysis and 100% conversion of glycerol after 24 h at +1.55 V. Furthermore, when these inexpensive catalysts were tested in tandem with cathodic CO2 electroreduction, the anodic Ni0.9Au0.1/C catalyst displayed the highest partial current density for CO and the lowest onset potential.