Role of V doping in core–shell heterostructured Bi2Te3/Sb2Te3 for hydrogen evolution reaction

Abstract

Non-noble metal-based materials as low-cost hydrogen evolution reaction (HER) catalysts are key materials for sustainable hydrogen energy production. Bismuth and antimony chalcogenides are among the hopeful candidates to achieve this goal. In this work, a V-doped Sb₂Te₃ encapsulated Bi₂Te₃ core-shell electrocatalyst (Bi₂Te₃/V_x-Sb₂Te₃) has been synthesized by a two-step solvothermal method. V doping adjusts the electronic structure of catalyst, dramatically enhances electric double layer capacitance (C_dl) of the catalyst, decreases charge transfer resistance (R_ct) of the catalyst and increases carrier concentration of the catalyst. Therefore, the V doping method increases the active sites on the surface of the material, and promotes the charge transfer and electron transport in the HER process. In addition, V doping can also adjust the hydrophilicity of the material surface, promote the release of hydrogen, and quickly re-expose the active sites. Bi₂Te₃/V_x-Sb₂Te₃ electrocatalysts exhibit brilliant HER activity and high stability in both acidic and alkaline electrolytes. This study uses the strategy of V doping to control the electronic structure of materials, which will provide suggestions for the design and preparation for other high-activity catalysts.