Pd–PdO Nanodomains on Amorphous Ru Metallene Oxide for High‐Performance Multifunctional Electrocatalysis

Abstract Developing highly efficient multifunctional electrocatalysts is crucial for future sustainable energy pursuits, but remains a great challenge. Herein, a facile synthetic strategy is used to confine atomically thin Pd–PdO nanodomains to amorphous Ru metallene oxide (RuO 2 ). The as‐synthesized electrocatalyst (Pd 2 RuOx‐0.5 h) exhibits excellent catalytic activity toward the pH‐universal hydrogen evolution reaction (η 10 = 14 mV in 1 m KOH, η 10 = 12 mV in 0.5 m H 2 SO 4 , and η 10 = 22 mV in 1 m PBS), alkaline oxygen evolution reaction (η 10 = 225 mV), and overall water splitting ( E 10 = 1.49 V) with high mass activity and operational stability. Further reduction endows the material (Pd 2 RuOx‐2 h) with a promising alkaline oxygen reduction activity, evidenced by high halfway potential, four‐electron selectivity, and excellent poison tolerance. The enhanced catalytic activity is attributed to the rational integration of favorable nanostructures, including 1) the atomically thin nanosheet morphology, 2) the coexisting amorphous and defective crystalline phases, and 3) the multi‐component heterostructural features. These structural factors effectively regulate the material's electronic configuration and the adsorption of intermediates at the active sites for favorable reaction energetics.