Fig. 1: Pressure-induced generation of heterogeneous electrocatalytic metal hydride surfaces for sustainable hydrogen transfer.

a Representative enzymatic metal hydride sites in nickel-iron hydrogenases. The shadow image representing a typical nickel-iron hydrogenase was plotted using the structure deposited in the Protein Data Bank (ID: 5ADU). Hydride formation generally involves complex electron transfer channels (e.g., chains of iron-sulfide clusters) and proton transfer channels (e.g., various amino acids). b Representative synthetic strategies for constructing homogeneous metal hydrides. A molecular metal hydride site is generally obtained by directly reacting precursors with toxic and reductive silanes, phosphines, or boranes. Recently, mediator-mediated hydride generation via photo- or electro-catalytic routes was also reported. c Representative synthetic strategies for fabricating bulk metal hydrides. The synthesis of bulk metal hydrides generally requires elevated temperature and pressure to facilitate hydrogen (H₂) dissociation and penetration. In addition, mechanochemical ball-milling methods adopting lithium or barium hydrides as precursors have also been reported. d Schematic illustration of the sustainable generation of heterogeneous electrocatalytic metal hydride surfaces via a facile high-pressure electrosynthesis methodology. More importantly, the obtained metal hydride surface is stable under ambient conditions and thus enables ambient-pressure electrocatalytic hydrogen processes.