Unveiling the synergy of piezoelectric polarization and oxygen vacancies in Y-doped SrTiO3 for enhanced N2 photofixation

Y-doped SrTiO 3 nanosheets were developed for piezophotocatalytic N 2 fixation. • 3%Y-SrTiO 3 achieves a robust ammonia yield of 642.66 μmol·g −1 ·h −1 under combined piezoelectric and visible-light excitation. • Piezoelectric field and oxygen vacancies synergistically boost charge separation and N 2 activation. Piezoelectric-assisted photocatalysis offers a sustainable route for N 2 fixation, but is often hampered by weak piezoelectric polarization and insufficient N 2 chemisorption/activation sites. Herein, we introduced aliovalent Y-doping into SrTiO 3 to induce lattice distortion for enhanced piezoelectric response and generated abundant oxygen vacancies for N 2 chemisorption. The optimized 3%Y-STO achieves a remarkable NH 3 yield of 642.66 μmol·g −1 ·h −1 under dual piezocatalytic and visible-light (PE/Vis) excitation. PFM measurements confirm the significantly improved piezoelectricity, and the resulting polarization field drives efficient carrier separation. DFT calculations reveal that Y-induced oxygen vacancies serve as active sites for N 2 adsorption, while the piezoelectric polarization facilitates the activation of adsorbed N 2 . This synergy between piezo-driven charge separation and defect-mediated N 2 activation enables efficient N 2 reduction. This work validates aliovalent doping as an effective dual-function strategy for sustainable piezophotocatalytic N 2 fixation. Download: Download high-res image (236KB) Download: Download full-size image