Mo‐Single‐Atom‐Enabled Functional‐Site‐Decoupled PdMo Catalysts for High‐Power Borane Fuel Cells and Alkaline Water Electrolysis

ABSTRACT Dimethylamine borane (DMAB) is a promising solid fuel for borane fuel cells due to its high hydrogen content and safety. However, the development is hindered by electrochemically sluggish DMAB oxidation reaction (DMABOR), since strongly adsorbed hydrogen‐containing reaction intermediates (*H) poison active sites. Herein, a Mo‐single‐atom‐enabled functional‐site‐decoupled PdMo catalyst is developed by combining functional‐site decoupling with atomic‐level oxophilic engineering. Spectroscopy and theoretical studies reveal that the catalyst comprises PdMo alloy particles (APs) and Mo single atoms (SAs), wherein alloyed Mo modulates electronic structure of Pd to weaken *H binding, and Mo SAs act as *OH‐affinitive Lewis‐acid sites that stabilize interfacial *OH, which is proposed to assist the oxidative removal of Pd‐bound *H. Notably, PdMo/KB was applied as the anode in direct DMAB fuel cells (D‐DMABFCs) for the first time, enabling an outstanding peak power density of 1195 mW cm −2 and stable operation for over 160 h, highlighting the potential of borane fuel cells as alternatives to hydrogen fuel cells. This functional‐site‐decoupling mechanism is further extended to alkaline hydrogen evolution reaction (HER), enabling a PdMo/KB‐based anion‐exchange membrane water electrolyzer (AEMWE) to reach 1.0 and 2.0 A cm −2 at 1.59 and 1.70 V, respectively, and operate stably for 1000 h.