Title: MoSe2-VSe2-NbSe2 Ternary Alloy Nanosheets to Boost Electrocatalytic Hydrogen Evolution Reaction

Authors: Ik Seon Kwon, In Hye Kwak, Getasew Mulualem Zewdie, Seung Jae Lee, Ju Yeon Kim, Seung Jo Yoo, Jin-Gyu Kim, Jeunghee Park*, and Hong Seok Kang*

DOI: 10.1002/adma.202205524

Abstract: Alloying of transition metal dichalcogenides (TMDs) is a pioneering method for engineering electronic structures with expanded applications. In this study, MoSe2-VSe2-NbSe2 ternary alloy nanosheets were synthesized via a colloidal reaction. The composition was successfully tuned over a wide range to adjust the 2H-1T phase transition. The alloy nanosheets consisted of miscible atomic structures at all compositions, which is distinct from the immiscible binary alloys. Compared to each binary alloy, the ternary alloys displayed higher electrocatalytic activity toward the hydrogen evolution reaction (HER) in an acidic electrolyte. The HER performance exhibited a volcano-type composition dependence, which is correlated with the experimental d-band center. Spin-polarized density functional theory calculations consistently predicted the homogenous atomic distributions. The Gibbs free energy of H adsorption and the activation barrier support that miscible ternary alloying greatly enhances the HER performance.