Regulating the Alloying Degree and Electronic Structure of Pt–Au Nanoparticles for High-Efficiency Direct C₂₊ Alcohol Fuel Cells

Direct alcohol fuel cells represent a promising green and sustainable route for chemical to electrical energy conversion; however, designing highly efficient electrocatalysts for the electro-oxidation of C2+ alcohol molecules is an ongoing challenge. Herein, we report a convenient room-temperature reduction method to fabricate a series of Pt–Au alloy catalysts with controllably tailored alloying degrees and particle diameters (4.6–7.9 nm) for enhancing the electro-oxidation capability toward C2+ alcohols. Benefiting from the strong electron interactions between Pt and Au, the electronic state and size of the alloy nanoparticles can be effectively optimized, alleviating the CO poisoning and aggregation problem of the catalytic species. As a result, the Pt45Au55 alloy nanoparticles grown in situ on carbon nanotubes (Pt45Au55/CNTs) show an enhanced C–C bond cleavage ability, as confirmed by a quantitative analysis of the final C2 oxidation products as well as by comparing the oxidation activity in different C1–C3 alcohols and other high-energy-density molecules. The Pt45Au55/CNTs catalyst exhibits excellent catalytic activity (1746 mA·mgPt–1), high CO tolerance, and good stability for the ethanol oxidation reaction (EOR) in an acidic medium. Moreover, the Pt38Au62/CNTs catalyst displays dramatically enhanced ethanol oxidation activity (13 993 mA·mgPt+Au–1) in an alkaline medium. The proposed rational design of Pt–Au alloy catalysts with controllable alloying degrees and particle sizes provides a feasible strategy for boosting the overall performance of Pt-based electrocatalysts for the direct C2+ alcohol fuel cells.