3D ordered macroporous copper nitride–titanium oxynitride as highly efficient electrocatalysts for universal-pH hydrogen evolution reaction

The demand for hydrogen for future clean energy has increased research interest in developing non-noble high-efficiency electrocatalysts for the hydrogen evolution reaction (HER). In this study, we prepared a copper nitride-loaded 3D ordered macroporous titanium oxynitride (Cu3N@3DOM-TiOxNy) via PS-metal sol–gel and ammonia annealing method. The present Cu3N@3DOM-TiOxNy as an electrocatalyst demonstrated high efficiency towards the HER, with low overpotentials ranging from 71 to 79 mV at a current density of 10 mA cm−2 in all-pH electrolyte. Additionally, the low Tafel slopes of the Cu3N@3DOM-TiOxNy revealed the fast electron transfer in the electrocatalytic process. In-depth investigation illustrated that the Cu3N with an extremely low activation barrier energy associated with rapid H2 release process works as the main active site and plays a pivotal role in efficiently electrocatalysing the HER. This work not only proposes a highly efficient, robust and low-cost copper-based all-pH HER electrocatalyst, but also demonstrates the significance of nano-engineering in developing next-generation electrocatalysts.