Efficient and Stable Electrocatalytic Oxygen Evolution from MoTe_x/Ni(OH)₂ Heterostructures

A design methodology is presented here for MoTe_x/Ni(OH)₂ heterostructured catalysts that enhance the oxygen evolution reaction (OER) in water electrolysis. This approach relies on the transfer of mechanically exfoliated MoTe₂ nanosheets to Au/Si substrates followed by electrochemical Te dissolution to induce defect-mediated, partial semiconducting (2H) to metallic (1T') phase transitions. Immersing the resulting MoTe_x into a nickel nitrate hydrate solution results in a heterostructure consisting of 2H-MoTe_x/Ni(OH)₂ and 1T'-MoTe_x/Ni(OH)₂ domains, which enables high stability and improved efficiency for the OER compared to IrO_x. Both machine-learning potential and density functional theory calculations searched and evaluated all atomic sites for this materials system, thus revealing the enhancement mechanisms of OER via four-electron transfer processes with lowered free energy barriers in the rate-determining steps.