Tunable Built‐In Electric Field in Ru Nanoclusters‐Based Electrocatalyst Boosts Water Splitting and Simulated Seawater Electrolysis

Abstract The development of bifunctional electrocatalysts suitable for a wide pH range and seawater splitting under simulated industrial electrolysis conditions is expected to advance practical applications of clean hydrogen energy. Here, the study reports a built‐in electric field approach to assemble heterogeneous Ru nanoclusters (Ru NCs) anchored in P,O co‐doped NiFe layered double hydroxide bifunctional electrocatalysts (Ru NCs/P,O‐NiFe LDH) for overall water splitting. It is revealed that the BEF ensures electron enrichment via unidirectional electron transfer from P,O‐NiFe LDH to Ru nanoclusters due to the difference in the corresponding Fermi levels. The optimized Ru NCs/P,O‐NiFe LDH/NF shows excellent electrocatalytic activity toward hydrogen evolution reaction, oxygen evolution reaction, and overall water splitting in a wide pH range, as well as simulated seawater electrolysis under industry‐relevant conditions. The long‐term catalyst stability under high currents and industrial process temperatures is also demonstrated. Density functional theory calculations further confirm that the active sites at the BEF interface effectively reduce the energy barrier of water electrolysis, thereby facilitating the electrocatalytic processes.