Unraveling Synergistic Effect of Defects and Piezoelectric Field in Breakthrough Piezo-Photocatalytic N 2 Reduction.

Piezo-photocatalysis is a frontier technology for converting mechanical and solar energies into crucial chemical substances, and has emerged as a promising and sustainable strategy for N 2 fixation. In this study, for the first time, we synergize defects and piezoelectric field to achieve unprecedented piezo-photocatalytic nitrogen reduction reaction (NRR) activity and unravel their collaborative catalytic mechanism over BaTiO 3 with tunable oxygen vacancies (OVs). The introduced OVs change the local dipole state to strengthen the piezoelectric polarization of BaTiO 3 , resulting in a more efficient separation of photogenerated carrier. Ti 3+ sites adjacent to OVs promote N 2 chemisorption and activation through d-π back-donation with the help of the unpaired d-orbital electron. Furthermore, a piezoelectric polarization field could modulate the electronic structure of Ti 3+ to facilitate the activation and dissociation of N 2 , thereby substantially reducing the reaction barrier of the rate-limiting step. Benefitting from the synergistic reinforcement mechanism and optimized surface dynamics processes, an exceptional piezo-photocatalytic NH 3 evolution rate of 106.7 μmol g -1 h -1 is delivered by BaTiO 3 with moderate OVs, far surpassing that of previously reported piezocatalysts/piezo-photocatalysts. This study provides new perspectives for the rational design of an efficient piezo-photocatalytic system for the NRR. This article is protected by copyright. All rights reserved.