Sustainable Conversion of Glycerol into Value-Added Chemicals by Selective Electro-Oxidation on Pt-Based Catalysts

Abstract Electro‐oxidation of glycerol affords a totally green route to produce high value‐added chemicals. Herein, we report a study on glycerol electro‐oxidation over a series of graphene nanosheet supported Pt (Pt/GNS), PtNi (PtNi/GNS), PtRu (PtRu/GNS), PtRh (PtRh/GNS), PtRuNi (PtRuNi/GNS), and PtRhNi (PtRhNi/GNS) catalysts in alkaline solution. The activity of the catalysts was evaluated by cyclic voltammetry, linear sweep voltammetry, and chronoamperometric measurements. The PtRh/GNS and PtRhNi/GNS catalysts exhibited superior activity in terms of higher current densities and lower onset potentials. The products of glycerol oxidation formed at potentials of −0.4, −0.1, and 0.2 V, were systematically analyzed by high performance liquid chromatography (HPLC). Five compounds as products from glycerol electro‐oxidation catalyzed by the prepared materials were found, including glyceraldehyde, glycolic acid, tartronic acid, glyceric acid and oxalate acid. The product distribution at the different potentials was investigated for all catalysts. A maximum glycolic acid selectivity of 65.4 % was obtained for the Pt/GNS catalyst at 0.2 V while a maximum glyceric acid selectivity of 47.7 % was achieved using the PtNi/GNS catalyst at −0.1 V. It was found that the introduction of Ru facilitated the formation of C3 products while the addition of Rh was beneficial for the formation of C2 products. Based on HPLC results, the pathways of glycerol electro‐oxidation by the prepared catalysts were proposed.