Transition metal chalcogenides based nanocomposites as efficient electrocatalyst for hydrogen evolution reaction over the entire pH range

In the present investigation, a series of noble metal-free, earth-abundant, inexpensive, efficient, and long-term stable electrocatalysts have been developed for hydrogen evolution reaction at different pH values. Transition metal chalcogenides nanocomposites, namely, CoTe2@CuTe, FeTe2@CuTe, CoSe2@CuS2, and FeSe2@CuSe2 have been synthesized via hydrothermal method and their electrocatalytic activity towards hydrogen evolution reaction at different pH values have been studied using different techniques. All the four investigated electrocatalysts are efficient towards the hydrogen evolution reaction. Out of these electrocatalysts, the sphere-like shaped CoTe2@CuTe nanocomposite exhibits outstanding electrocatalytic activity towards hydrogen evolution reaction at different pH values. The novelty of the designed catalyst is its specific shape, low cost and high activity towards HER. The overpotential of CoTe2@CuTe nanocomposite electrocatalyst to achieve current density of 10 mA/cm(2) has been found as 68,106, and 125.8 mV in 0.5 M H2SO4 (pH < 0), 1.0 M KOH (pH approximate to 14) and 1.0 M PBS (pH approximate to 7), respectively and corresponding Tafel slope as 59.94, 67.6 and 69.53 mV/decade, respectively. Thus, CoTe2@CuTe nanocomposite exhibits good electrocatalytic activity in acidic, basic, and neutral medium. It possesses significant Brunauer-Emmett-Teller surface area, synergic effect, small charge transfer resistance, good conductivity, considerable electrochemically sur- face area (ECSA) value, and higher number of active sites. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.