Synergistic electronic-geometric regulation of Pt-based intermetallics resolves the activity-selectivity trade-off in borohydride oxidation

Direct borohydride fuel cells (DBFCs) exhibit a high theoretical energy density of 9946 Wh L−1, yet their application is hindered by the competition between the target 8-electron borohydride oxidation reaction (8e-BOR) and the parasitic incomplete borohydride oxidation reaction (i-BOR). Herein, we resolve this activity-selectivity trade-off by synergistically regulating the electronic and geometric structures of ordered Pt-based intermetallic catalysts (IMCs). Pt-Fe orbital coupling lowers the d-band center by 0.37 eV, weakening the adsorption of intermediates that trigger i-BOR. Meanwhile, the ordered lattice isolates Pt sites, disrupting the continuous Pt-Pt ensembles required for i-BOR. This dual regulation effectively suppresses hydrogen evolution, yielding a near-ideal electron transfer number of 7.72. A DBFC using a Pt-Fe IMC anode delivers a peak power density of 1208 mW cm−2 with 60.3% fuel utilization. Scalability is further demonstrated through a 1.3 kW industrial stack, confirming its practical potential. This work provides a general strategy for managing selectivity in complex electrocatalytic systems. Direct borohydride fuel cells offer a high energy density but suffer from incomplete fuel oxidation on conventional catalysts. Here, the authors show ordered Pt-Fe intermetallic catalysts suppress parasitic hydrogen release and improve fuel utilization, with a peak power density of 1208 mW cm−2.