Co 4 N-WN x composite for efficient piezocatalytic hydrogen evolution.

A dual-phase transition metal nitride (TMN) based Co 4 N-WN x system has been fabricated using nitridation of CoWO 4 . The interface between centrosymmetric Co 4 N and non-centrosymmetric WN x 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 Co 4 N-WN x 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. Co 4 N-WN x can also help achieve simultaneous piezocatalytic hydrogen production and RhB degradation. This work provides a novel strategy for designing efficient piezocatalytic materials.