Zhang Yanke, Li Wan, France Liam John, Chen Zhihang, Zeng Qiang, Guo Dawei, Li Xuehui
School of Chemistry and Chemical Engineering, Pulp & Paper Engineering State Key Laboratory of China, South China University of Technology, Guangzhou 510640, P. R. China.
Guangdong Key Laboratory of Water and Air Pollution Control, South China Institute of Environmental Science, Ministry of Environmental Protection, Guangzhou 510655, P. R. China.
ACS Omega. 2019 May 17;4(5):8681-8692. doi: 10.1021/acsomega.9b00445. eCollection 2019 May 31.
Annealing strategies for the citrate complexation-combustion method have been explored as a simple approach for improving the catalytic activity of mixed Cr-Mn oxides for the NH-selective catalytic reduction of NO . Materials prepared at 300 and 400 °C possess largely amorphous structures, consistent with highly dispersed Cr/Mn components. Annealing at 300 °C for 10 h facilitates the formation of catalysts possessing the largest surface area, reducibility, acidity, and activity window (92-239 °C), while areal activity is measured at 3.8 nmol s m and is comparable to values obtained for materials prepared at 400 °C. Conversely, shorter annealing times of 1 and 5 h at 300 °C produce materials that transform NO about 2-3 times faster at equivalent surface area. Characterization demonstrates that simple annealing strategies have significant impact on the physiochemical and textural properties of these materials. Moreover, reducibility, O species, and acidity were correlated against areal activity, but only the latter exhibited a near-linear correlation, indicating its dominance in controlling surface reaction rates.
已探索了柠檬酸盐络合燃烧法的退火策略，作为提高混合Cr-Mn氧化物对NH₃选择性催化还原NO活性的一种简单方法。在300和400℃制备的材料具有很大程度上的非晶结构，这与高度分散的Cr/Mn组分一致。在300℃退火10小时有助于形成具有最大表面积、还原性、酸度和活性窗口（92-239℃）的催化剂，而面活性为3.8 nmol s⁻¹ m⁻²，与在400℃制备的材料所获得的值相当。相反，在300℃下1小时和5小时的较短退火时间产生的材料，在等效表面积下将NO转化的速度快约2-3倍。表征表明，简单的退火策略对这些材料的物理化学和织构性质有显著影响。此外，还原性、O物种和酸度与面活性相关，但只有后者表现出近乎线性的相关性，表明其在控制表面反应速率方面占主导地位。
