Theory-assisted design of transition-metal-doped Bi5O7I for efficient contact-electro-catalytic hydrogen evolution

Contact-electro-catalysis (CEC) offers a promising mechanochemical pathway for harvesting ubiquitous mechanical energy to drive hydrogen evolution. Bismuth oxyhalides are attractive CEC candidates owing to their layered polar structures and strong internal electric fields, yet their performance is limited by weak interactions between surface sites and adsorbates. Here, we combine density functional theory screening with experimental validation to investigate transition-metal-doped Bi 5 O 7 I as vibration-driven hydrogen evolution catalysts. Ten dopants ( M  = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) were systematically evaluated with respect to doping feasibility, water adsorption, and electronic characteristics. Among them, Fe-doped Bi 5 O 7 I was identified as a representative system offering a favorable balance of activity, abundance, and cost. Guided by theoretical insights, Fe/Bi 5 O 7 I nanorods were synthesized and demonstrated a hydrogen evolution rate of 2004.11 μmol·g −1 ·h −1 under ultrasonic stimuli. Mechanistic analyses further revealed that Fe doping enriches the electronic states near the Fermi level, enhances water adsorption, and reduces reaction barriers, while strain introduced by mechanical stimulation provides additional electronic modulation. This work establishes a theory-assisted framework for designing transition-metal-doped Bi 5 O 7 I catalysts and highlights the potential of CEC as a sustainable approach to hydrogen production.