Tuning the Tin Oxide-Carbon Composite Support to Deposit Rh Nanoparticles for Glycerol-to-Carbonate Electro-Conversion

Abstract

Glycerol Electrooxidation Reaction (GEOR) has been herein investigated on Rh/C and Rh/SnO2-C prepared by polyol method. The particle mean sizes were found to be 2.0 and 1.8 nm in Rh/C and Rh/SnO2-C, respectively. The alloying degree reached 63% in Rh/SnO2-C, confirming a Sn-Rh alloy formation. The activity towards GEOR on Rh/SnO2-C was almost 5-fold higher than on Rh/C, as demonstrated by electrochemical measurements in alkaline medium. This trend indicated the beneficial effect of the SnO2-C carbon-oxide composite support in the catalyst composition. Analysis of the products generated after the bulk electrolysis using high-performance liquid chromatography (HPLC) and FTIRS demonstrated that at 0.55 V vs RHE the main reaction products were glycerate ion and carbonate (CO3 2−). Then, a C–C–C cleavage was demonstrated with the CO3 2− formation at low potentials. During the testings conducted in a home-made acrylic direct glycerol fuel cell at room temperature in 0.5 mol l−1 NaOH, the maximum power density (390 μW cm−2) obtained on a Rh/SnO2 anode, was 5-fold higher than that on Pd/C. These testings demonstrated that the co-generation of sustainable energy and value-added products is a promising way to valorize glycerol.