Asymmetrically strained hcp rhodium sublattice stabilized by 1D covalent boron chains as an efficient electrocatalyst

RhB comprising an asymmetrically strained hcp Rh sublattice is identified as a hydrogen-evolving electrocatalyst with Pt-like activity, due to its optimized electronic structure primarily controlled by Rh(d)–B(s,p) orbital hybridization.