Modification of Nickel Surfaces by Bismuth: Effect on Electrochemical Activity and Selectivity toward Glycerol

Herein, we study the effect of adding bismuth to Ni-nanostructured catalysts (NixBi1–x, x = 100–90 at. %) for glycerol electro-oxidation in alkaline solution by combining physiochemical, electrochemical, and in situ infrared spectroscopy techniques, as well as continuous electrolysis with HPLC (high-performance liquid chromatography) product analysis. The addition of small quantities of Bi (<20 at. %) to Ni nanoparticles led to significant activity enhancement at lower overpotentials, with Ni90Bi10 displaying an over 2-fold increase compared to Ni. Small quantities of bismuth actively affected the reaction selectivity of Ni by suppressing the pathways with C–C bond cleavage, hindering the production of carbonate and formate and improving the formation of tartronate, oxalate, and glycerate. Furthermore, the effect of aging on NixBi1–x catalysts was investigated, resulting in structural modification from the Ni–Bi double shell/core structure to Bi decorated on the folded Ni sheet, thus enhancing their activity twice after 2 weeks of aging. NiBi catalysts are promising candidates for glycerol valorization to high-value-added products.