Abstract
The oxidation rate of NO to NO(2) is a critical parameter in the removal of NO(x) within selective catalytic reduction (SCR) systems. LaCoO(3-δ) is a kind of potential catalyst to enhance the oxidation of NO to NO(2), it may offers an economic and stable alternative to noble metal catalysts, particularly at elevated temperatures. This study aimed to enhance the catalytic efficiency of LaCoO(3-δ) through strontium (Sr) doping. La(1-x)Sr(x)CoO(3-δ) (with varying x values of 0.1, 0.2, 0.3, 0.4) was synthesized using a sol-gel method. La(1-x)Sr(x)CoO(3-δ) exhibited superior NO oxidation catalytic activity compared to LaCoO(3-δ), with the most notable enhancement observed at x = 0.3 (84 % conversion). This improvement can be attributed to the substitution of La(3+) with Sr(2+), which induces lattice distortion and charge imbalance, thereby creating more oxygen vacancies that enhance the catalytic oxidation capability of La(1-x)Sr(x)CoO(3-δ). However, it's important to note that an excessive amount of Sr can result in the formation of SrCO(3) deposits on the surface of La(1-x)Sr(x)CoO(3-δ), thereby diminishing its catalytic oxidation performance. The catalytic oxidation reaction behavior adhered most closely to the O(2)-adsorbed E-R model, the surface defects in La(1-x)Sr(x)CoO(3-δ) playing a pivotal role in the catalytic reaction.