Zhao Jiuhu, Jiang Jingjing, Chen Guanyu, Wang Meng, Zuo Xiaoyuan, Bi Yanjiao, Zhu Rongshu
State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Economics and Management, Harbin Institute of Technology, Shenzhen 518055, China.
School of Eco-Environment, Harbin Institute of Technology, Shenzhen 518055, China.
Molecules. 2025 Jun 21;30(13):2691. doi: 10.3390/molecules30132691.
The selective catalytic reduction of NO with CH (CH-SCR) holds the potential to simultaneously abate harmful NO and CH greenhouse gases. In this study, a series of bimetallic M-In/H-SSZ-39 catalysts (where M represents Cr, Co, Ce, and Fe) were prepared via an ion exchange method and subsequently evaluated for their CH-SCR activity. The influences of the preparation parameters, including the metal ion concentration and calcination temperature, as well as the operating conditions, such as the CH/NO ratio, O concentration, water vapor content, and gas hourly space velocity (GHSV), on the catalytic activity of the optimal Cr-In/H-SSZ-39 catalyst were meticulously examined. The results revealed that the Cr-In/H-SSZ-39 catalyst exhibited peak CH-SCR catalytic performance when the Cr(NO) concentration was 0.0075 M, the In(NO) concentration was 0.066 M, and the calcination temperature was 500 °C. Under optimal operating conditions, namely GHSV of 10,000 h, 400 ppm NO, 800 ppm CH, 15 vol% O, and 6 vol% HO, the NO conversion rate reached 93.4%. To shed light on the excellent performance of Cr-In/H-SSZ-39 under humid conditions, a comparative analysis of the crystalline phase, chemical composition, pore structure, surface chemical state, surface acidity, and redox properties of Cr-In/H-SSZ-39 and In/H-SSZ-39 was conducted. The characterization results indicated that the incorporation of Cr into In/H-SSZ-39 enhanced its acidity and also facilitated the generation of InO active species, which promoted the oxidation of NO and the activation of CH, respectively. A synergistic effect was observed between Cr and In species, which significantly improved the redox properties of the catalyst. Consequently, the activated CH could further interact with InO to produce carbon-containing intermediates such as HCOO, which ultimately reacted with nitrate-based intermediates to yield N, CO, and HO.
用CH选择性催化还原NO（CH-SCR）具有同时减少有害NO和CH温室气体的潜力。在本研究中，通过离子交换法制备了一系列双金属M-In/H-SSZ-39催化剂（其中M代表Cr、Co、Ce和Fe），随后对其CH-SCR活性进行了评估。精心研究了制备参数（包括金属离子浓度和煅烧温度）以及操作条件（如CH/NO比、O浓度、水蒸气含量和气体时空速（GHSV））对最佳Cr-In/H-SSZ-39催化剂催化活性的影响。结果表明，当Cr(NO)浓度为0.0075 M、In(NO)浓度为0.066 M且煅烧温度为500℃时，Cr-In/H-SSZ-39催化剂表现出CH-SCR催化性能峰值。在最佳操作条件下，即GHSV为10,000 h、400 ppm NO、800 ppm CH、15 vol% O和6 vol% HO时，NO转化率达到93.4%。为了阐明Cr-In/H-SSZ-39在潮湿条件下的优异性能，对Cr-In/H-SSZ-39和In/H-SSZ-39的晶相、化学成分、孔结构、表面化学状态、表面酸度和氧化还原性能进行了对比分析。表征结果表明，将Cr引入In/H-SSZ-39增强了其酸度，还促进了InO活性物种的生成，分别促进了NO的氧化和CH的活化。观察到Cr和In物种之间的协同效应，显著改善了催化剂的氧化还原性能。因此，活化的CH可以进一步与InO相互作用生成含碳中间体如HCOO，最终与基于硝酸盐的中间体反应生成N、CO和HO。
