Junhwi Han, Myeong Kyun Nam, Seunghun Shin, Iaan Cho, Hotae Jeon, Jaewon Heo, Jaehyun Lee, Min Kyung Cho, Daniel J. Preston, Mark C. Hersam, In Soo Kim, Bonggeun Shong, Won‐Kyu Lee
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 MoTe 2 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.