Cu改性ZIF-67衍生的Co3O4/C催化剂的CO-SCR脱硝特性

采用CO气体对NO进行选择性催化还原(CO-SCR)是一种有前景的脱硝技术.目前已报道的CO-SCR催化剂的脱硝特性主要是在无氧条件下开展的研究,考虑到实际应用情况,探究一种在有氧环境中具有较高脱硝效率的催化剂是很有必要的.作为一种新型功能性材料的金属有机骨架是脱硝催化剂的优良载体,其中ZIFs系列具有优良的性能.引入Cu对ZIF-67衍生的Co₃O₄/C进行改性,通过浸渍法在载体上负载铜后,热解氧化获得一系列CuO_x/Co₃O₄/C催化剂.利用ICP、 SEM、 XRD、 TEM、 TGA、 XPS、 BET和H₂-TPR等技术对催化剂的物理化学性质进行表征,结果表明,由于Cu的引入增加了表面的氧空位,改善了氧化还原能力,进而提高了催化剂脱硝活性.在制备的一系列催化剂中, 8.0 CuO_x/Co₃O₄/C在300℃时即可达到约95%NO转化率,并且其N₂选择性也达到9...

Selective Catalytic Reduction of NO by CO over Cu-doped Co3O4/C Catalysts Derived from ZIF-67

NOx from industrial gas or motor vehicle exhaust is bad for the environment and the human. Selective catalytic reduction of NO by CO gas (CO-SCR) is a promising denitrification technology. At present, the denitration characteristics of CO-SCR catalysts have been reported mainly under anaerobic conditions. Considering the practical application, it is necessary to explore a catalyst with high denitration efficiency in an aerobic environment. As a new functional material, the metal-organic framework is an excellent carrier of denitration catalyst, among which the ZIFs series has excellent performance. ZIF-67-derived Co3O4/C was modified by introducing Cu, and a series of CuOx/Co3O4/C catalysts were obtained by pyrolysis and oxidation after loading copper on the carrier by the impregnation method. The physical and chemical characteristics of catalysts were characterized by ICP, SEM, XRD, TEM, TGA, XPS, BET, and H2-TPR techniques. The introduction of Cu metal will not damage the original crystal structure of the carrier, according to the XRD, and will instead promote the dispersion of surface materials, suggesting that copper has a promoting influence on the dispersion of cobalt. This conclusion was further supported by XPS, which demonstrated that the promotion effect might increase the number of oxygen vacancies on the surface of the catalyst. BET discovered that copper promotes cobalt dispersion, which promotes the dispersion of metal oxides to prevent the emergence of big holes. Additionally, according to H2-TPR results, we discovered that the addition of Cu caused the reduction peak of the catalyst to move toward the low-temperature region, indicating that Cu improved the reducing ability of the catalyst. In the series of catalysts prepared, 8.0 CuOx/Co3O4/C achieves approximately 95% NO conversion at 300 °C and N2 selectivity of 98%.