Tailoring Electron Redistribution and Hydrogen Adsorption in Epitaxial MnTe/Cr2Te3 Semiconductor/Metal Heterojunction for Highly Efficient Hydrogen Evolution Catalysis

Abstract

Electronic structure engineering and interface chemistry is critical for optimizing hydrogen evolution reaction (HER) electrocatalysts. Here, we report a solution-based synthesis of Cr-doped MnTe nanowires and a Cr2Te3/MnTe/Cr2Te3 metal/semiconductor/metal heterojunctions that achieves outstanding HER performances. The epitaxial interface, defined by coherent lattice alignment between MnTe and Cr2Te3, enables directional electron transfer from the metallic metallic Cr2Te3 caps to the MnTe semiconductor, as supported by XPS and Bader charge analyses. DFT calculations reveal that Cr doping enhances conductivity and introduces active electronic states, while the heterojunction simultaneously optimizes hydrogen adsorption free energy (ΔGH*) and reduces HER reaction barriers. As a result, the catalyst achieves a low overpotential of -0.354 V at 10 mA cm-2 and a small Tafel slope of 53.9 mV dec-1, surpassing its individual components. This work offers strategic guidance for designing highly efficient non-noble metal HER electrocatalysts via interface engineering and electronic structure tuning.