Shape-induced d-band center optimization of PdBiNi nanocubes for exclusive oxidation of glycerol into C3 products

The electrocatalytic oxidation of glycerol toward high-value three-carbon (C3) products on Pd-based catalysts presents a promising strategy for upgrading and conversion of glycerol, a major carbon-rich byproduct from biodiesel manufacturing. However, C3 intermediates often adsorb too tightly on Pd-based catalyst surfaces during glycerol oxidation, leading to C-C bond cleavage and downstream formation of C2 and C1 products. Herein, cubic-shaped PdBi nanoparticles with tunable Ni-doping levels are successfully synthesized through a one-step solvothermal method. Owing to the downshift of d-band center originating from the introduction of Bi and Ni as well as the cubic shape, the PdBiNi ternary nanocubes (NCs) exhibit excellent electrocatalytic performance in glycerol oxidation reaction (GOR) in alkaline electrolytes. Specifically, the Pd83Bi12Ni5 NCs with the lowest d-band center exhibit a specific activity of 61.12 mA cmgeo-2 and a mass activity of 5.34 A mgPd-1, respectively. Notably, the Faradaic efficiency (FE) toward C3 products exceeds 97%. In-situ Fourier transform infrared spectroscopy shows that key C3 intermediates are easily desorbed from catalyst surface, thereby suppressing C-C bond cleavage and thus preventing overoxidation into low-value products. In addition, Pd83Bi12Ni5 NCs possess long-term durability over the course of 16 cycles (1 hour/cycle) with a FE for value-added C3 products between 92.5% and 97.6% upon scale-up deployment in a flow electrolyzer, validating its feasibility in practical operations.