Effective PtRu-Based Multicomponent Alloy Catalysts for Selective Conversion of Glycerol to Value-Added Products

The selective electrooxidation of glycerol to value-added products is an effective method to address the surplus glycerol derived from biodiesel production. In this study, a series of carbon-supported non-precious metal-doped PtRu-based multicomponent alloy catalysts (PtRuFeCrNi/C, PtRuMnCrNi/C, PtRuSnCrNi/C and PtRuCuCrNi/C) were prepared by a one-pot solvothermal method. The effects of elemental compositions on the catalyst morphology, catalytic activity, and the selectivity of the glycerol conversion to high-value products were investigated. XRD patterns verify the formation of single-phase face-centered cubic (fcc) solid solutions for the metallic moieties in all as-prepared catalysts. The PtRuCuCrNi/C exhibits a unique cluster-like nanoflower structure and demonstrates the lowest onset potential, smallest charge transfer resistance, and excellent catalytic activity for glycerol oxidation, with a mass activity of 3.18 A mgPtRu−1, which is 3.46 times that of the commercial Pt/C (20 wt%) catalysts (0.92 A mgPt−1). This performance improvement is attributed to the significant synergistic effect resulting from the optimized compositions. The selectivities of the PtRuFeCrNi/C, PtRuMnCrNi/C and PtRuCuCrNi/C catalysts toward glyceric acid in the detected liquid products are 81.4%, 83.0% and 78.9%, respectively. Over PtRuCuCrNi/C, formic acid content increases at high potentials, as glycerol tends to undergo deep oxidation. Our results reveal that the selectivity toward high-value products in glycerol electrooxidation depends not only on catalyst compositions, but also on the applied potential. This work offers insights into the rational design and development of alloy electrocatalysts for alcohol electrooxidation.