Boron‐Intercalation‐Induced Phase Evolution of Rh Metallene for Energy‐Saving H2 Production by H2O2 Oxidation Coupled with Water Electrolysis

Abstract Tailoring the morphology and crystal structure of metallene is critical to improve its electrocatalytic performance. In this work, hetero‐phase RhB metallene ( h ‐RhB metallene) with amorphous/crystalline structure is readily prepared by a two‐step method. The h ‐RhB metallene is very unique in its non‐metallic heteroatom doping and amorphous/crystalline structure. Benefiting from the unique metallene structure and the optimized electronic states induced by the incorporation of B atoms, the h ‐RhB metallene exhibits superior performance for hydrogen evolution reaction and hydrogen peroxide electro‐oxidation reaction (HPOR). When coupled with HPOR, the h ‐RhB metallene|| h ‐RhB metallene water electrolysis two‐electrode system exhibits a lower cell voltage of 0.379 V (@ 10 mA cm −2 ) compared with the overall water splitting (1.35 V). The presented synthetic method provides a powerful strategy to design metallene with hetero‐phase for energy‐saving H 2 production.