Tungsten-based porous thin-films for electrocatalytic hydrogen generation

Developing inexpensive and efficient electrocatalysts without using precious metals for the hydrogen evolution reaction (HER) is essential for the realization of economical clean energy production. Here we demonstrate a facile approach to access interconnected three-dimensional (3-D) porous tungsten-based (WS₂ and WC) thin-films without using any templates. Benefiting from the 3-D open frameworks of these highly porous thin-films, there are enormous amounts of exposed active sites and efficient mass transport in favor of the HER. Both electrodes exhibit excellent catalytic activity towards HER with onset overpotentials of ∼100 mV for WS₂ and ∼120 mV for WC, and similar Tafel slopes of ∼67 mV per decade. The long-term operation of these thin-film electrodes is confirmed by their electrochemical stability test. With the low loading mass (∼80 and ∼160 μg cm^-2 for WS₂ and WC, respectively), these porous thin-films are among the best tungsten-based HER electrocatalysts.