Ti3+ defects bridge a Cu-Nx structure to improve electron transport for photocatalytic nitrogen fixation

Abstract

Photocatalytic nitrogen reduction (PNRR) has emerged as a promising alternative for the sustainable and distributed production of NH3. In this paper, structures consisting of Cu-Nx (electron aggregates) bridged on electron donors (Ti3+ defects) are demonstrated as PNRR catalysts. The surface charge polarisation of Cu-N3-Ti3+ enhances the N2 adsorption capacity of PNRR and exhibits a catalytic ammonia production rate of 29 umol.g−1.h−1. More importantly, DFT calculations find the Cu-N3 adsorption of N2 (ΔG*NN = −0.09 eV) to be in a preferred state (Cu-N2 compared to Cu-N1), significantly hindering the competitive hydrogen evolution reaction, reducing the energy barrier of the PNRR reaction (*NN→*NNH) and promoting the activation of the N-N bond. The concept of synergistically catalysing the construction of efficient charge channels can be generalised for other system materials, thereby creating new opportunities for the development of such adjuvants.