A comparative investigation of NdSrCu1-xCo(x)O4-delta and Sm1.8Ce0.2Cu1-xCo(x)O4-delta (x: 0-0.4) for NO decomposition.
A series of single-phase T-structured NdSrCu1-xCo(x)O4-delta with oxygen vacancies and T'-structured Sm1.8Ce0.2Cu1-xCo(x)O4-delta (x: 0-0.4) with oxygen excess were prepared using ultrasound-assisted citric acid complexing method, and characterized by means of techniques such as thermogravimetric analysis and NO temperature-programmed desorption (NO-TPD). The catalytic activities of these materials were evaluated for the decomposition of NO. It was found that the NdSrCu1-xCo(x)O4-delta catalysts were of oxygen vacancies whereas the Sm1.8Ce0.2Cu1-xCo(x)O4-delta ones possessed excessive oxygen (i.e., over-stoichiometric oxygen); with arise in Co doping level, the oxygen vacancy density of NdSrCu1-xCo(x)O4-delta decreased while the over-stoichiometric oxygen amount of Sm1.8Ce0.2Cu1-xCo(x)O4-delta increased. The NO-TPD results revealed that NO could be activated much easier over the oxygen-deficient perovskite-like oxides than over the oxygen-excessive perovskite-like oxides, with the NdSrCuO3.702 catalyst showing the best efficiency in activating NO molecules. Under the conditions of 1.0% NO/helium, 2800 hr(-1), and 600-900 degrees C, the catalytic activity of NO decomposition followed the order of NdSrCuO3.702 > NdSrCu0.8Co0.2O3.736 > NdSrCu0.6Co0.4O3.789 > Sm1.8Ce0.2Cu0.6Co0.4O4.187 > Sm1.8Ce0.2Cu0.8Co0.2O4.104 > Sm1.8Ce0.2CuO4.045, in concord with the sequence of decreasing oxygen vacancy or oxygen excess density. Based on the results, we concluded that the higher oxygen vacancy density and the stronger Cu3+/Cu2+ redox ability of NdSrCu1-xCo(x)O4-delta account for the easier activation of NO and consequently improve the catalytic activity of NO decomposition over the catalysts.
Deng
Jiguang
J
Laboratory of Catalysis Chemistry and Nanoscience, Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China. dengjiguang@emails.bjut.edu.cn
Zhang
Lei
L
Xia
Yunsheng
Y
Dai
Hongxing
H
He
Hong
H
D002384:Catalysis; D004785:Environmental Pollutants / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D013696:Temperature
D004785:Environmental Pollutants; D008670:Metals; D009569:Nitric Oxide