Co<inf>4</inf>N-WN<inf>x</inf> composite for efficient piezocatalytic hydrogen evolution

A dual-phase transition metal nitride (TMN) based Co4N-WNx system has been fabricated using nitridation of CoWO4. The interface between centrosymmetric Co4N and non-centrosymmetric WNx promotes charge carrier separation. This system also shows piezoelectric behavior. The piezoelectric property has been proved using piezoelectric force microscopy (PFM) measurements. In addition, modulating the non-centrosymmetric structure of Co4N-WNx allows a hydrogen production rate of about 262.7 μmol g−1 h−1 in pure water. We also show that the piezocatalytic hydrogen evolution efficiency is satisfactory. Co4N-WNx can also help achieve simultaneous piezocatalytic hydrogen production and RhB degradation. This work provides a novel strategy for designing efficient piezocatalytic materials.