Breaking Surface Atomic Monogeneity of Rh2P Nanocatalysts by Defect‐Derived Phosphorus Vacancies for Efficient Alkaline Hydrogen Oxidation

Breaking atomic monogeneity of catalyst surfaces is promising for constructing synergistic active centers to cope with complex multi‐step catalytic reactions. Here, we report a defect‐derived strategy for creating surface phosphorous vacancies (P‐vacancies) on nanometric Rh2P electrocatalysts toward drastically boosted electrocatalysis for alkaline hydrogen oxidation reaction (HOR). This strategy disrupts the monogeneity and atomic regularity of the thermodynamically stable P‐terminated surfaces. Density functional theory calculations initially verify that the competitive adsorption behavior of Had and OHad on perfect P‐terminated Rh2P{200} facets (p‐Rh2P) can be bypassed on defective Rh2P{200} surfaces (d‐Rh2P). The P‐vacancies enable the exposure of sub‐surface Rh atoms to act as exclusive H adsorption sites. Therein, the Had cooperates with the OHad on the peripheral P‐sites to effectively accelerate the alkaline HOR. Defective Rh2P nanowires (d‐Rh2P NWs) and perfect Rh2P nanocubes (p‐Rh2P NCs) are then elaborately synthesized to experimentally represent the d‐Rh2P and p‐Rh2P catalytic surfaces. As expected, the P‐vacancy‐enriched d‐Rh2P NWs catalyst exhibits extremely high catalytic activity and outstanding CO tolerance for alkaline HOR electrocatalysis, attaining 5.7 and 14.3 times mass activity that of p‐Rh2P NCs and commercial Pt/C, respectively. This work sheds light on breaking the surface atomic monogeneity for the development of efficient heterogeneous catalysts. Defect‐derived surface phosphorus vacancies on ultrathin Rh2P nanowires break the monogeneity and atomic regularity of thermodynamically stable P‐terminated surfaces, which can create additional Rh sites to act as exclusive H adsorption sites and diminish the inhibition effect of the interfacial water network to achieve drastically improved alkaline HOR electrocatalysis.