Title

Perovskite LaFeO3-SrTiO3 composite for synergistically enhanced NO removal under visible light excitation

Authors

Zhang, Q ; Huang, Y; Peng, SQ; Zhang, YF; Shen, ZX; Cao, JJ; Ho, WK; Lee, SC; Pui, DYH

Abstract

Perovskite oxides (ABO₃) are widely studied as excellent sorbing and catalytic materials for NO_xabatement in automobile or stationary depollution processes, and recently they have attracted significant interest in solar conversion reactions due to the flexible composition, facile optical and electronic tuning properties. In this work, perovskite LaFeO₃microspheres were synthesized and employed as photo catalysts to remove parts-per-billion level NO, and it is found that the photocatalytic efficiency was dramatically improved by coupling with SrTiO₃nanocubes. The LaFeO₃-SrTiO₃composite with proper mass ratio (0.3-1) displayed 3.1 and 4.5 fold enhancement in NO removal rate as compared to the pristine LaFeO₃and SrTiO₃, respectively. Moreover, the LaFeO₃-SrTiO₃composite exhibited decreased NO₂yield possibly due to the basic surface property of strontium sites. The synergistically improved activity was due to broad visible light harvest, enlarged surface area, and most importantly, the depressed surface charge recombination originating from the perfectly matched LaFeO₃-SrTiO₃interface and facile charge transfer along the staggered band alignment. The temperature programmed desorption (TPD) analysis revealed that the composite had efficient chemisorption for NO. Further, the electron spin resonance (ESR) combined with the radical scavenger tests and density functional theory (DFT) calculations suggested that the photocatalytic NO oxidation via superoxide radicals (O-center dot₂^-) from SrTiO₃and direct hole (h⁺) transfer from LaFeO₃might be the predominant routes. We believe that this study provides some new insights into perovskite nanomaterials as photocatalyst for NO_xabatement under ambient conditions.

Corresponding author

Huang Yu，Cao Junji

Volume

204

Issue

Page

346-357

Pub year

2017

Publication name

APPLIED CATALYSISB-ENVIRONMENTAL

Details

http://www.sciencedirect.com/science/article/pii/S0926337316309201