Heterophase-Interfaced Ultrasmall Pt−In Nanocatalysts: Multifunctional Catalysis in Fuel Cells

Aiming at the key issues of high cost, poor stability, and insufficient multifunctional catalytic performance of platinum-based electrocatalysts for fuel cells, a series of Pt−In nanocatalysts with triphasic heterointerfaces (face-centered cubic phase, ordered intermetallic phase, and amorphous phase) were prepared in one step via a liquid-phase reduction method in this work. The regulatory mechanisms of PDDA modification and the Pt−In atomic ratio on the catalyst structure were systematically investigated, and their catalytic performance in various electrocatalytic reactions of fuel cells was thoroughly characterized. The results demonstrated that PDDA not only realized the regulation of ultrasmall size and uniform dispersion of Pt−In nanoparticles but also played a pivotal role in the formation of triphasic heterointerfaces. The optimal atomic ratio of the triphasic PtIn0.701 nanocatalyst exhibited enhanced catalytic activity compared to the biphasic Pt−In catalyst and commercial Pt/C catalyst in methanol oxidation reaction, ethanol oxidation reaction, formic acid oxidation reaction, hydrogen oxidation reaction, and oxygen reduction reaction. The combination of theoretical and experimental studies confirmed that the geometric and electronic synergetic effects of the triphasic heterointerfaces were the core factors for the enhanced catalytic performance. This study lays a foundation for the development of low-cost and multifunctional electrocatalytic systems with promising potential for fuel cells.