Room-temperature sputtered electrocatalyst WSe2 nanomaterials for hydrogen evolution reaction

The low-temperature physical vapor deposition process of atomically thin two-dimensional transition metal dichalcogenide（2D TMD） has been gaining attention owing to the cost-effective production of diverse electrochemical catalysts for hydrogen evolution reaction（HER） applications. We, herein, propose a simple route toward the cost-effective physical vapor deposition process of 2D WSelayered nanofilms as HER electrochemical catalysts using RF magnetron sputtering at room temperature（<27℃）. By controlling the variable sputtering parameters, such as RF power and deposition time, the loading amount and electrochemical surface area（ECSA） of WSefilms deposited on carbon paper can be carefully determined. The surface of the sputtered WSefilms are partially oxidized, which may cause spherical-shaped particles. Regardless of the loading amount of WSe, Tafel slopes of WSeelectrodes in the HER test are narrowly distributed to be ～120–138 mV dec, which indicates the excellent reproducibility of intrinsic catalytic activity. By considering the trade-off between the loading amount and ECSA, the best HER performance is clearly observed in the 200 W-15 min sample with an overpotential of 220 mV at a current density of 10 mA cm. Such a simple sputtering method at low temperature can be easily expanded to other 2D TMD electrochemical catalysts, promising potentially practical electrocatalysts.