前驱体对MnO2同时催化脱除氮氧化物与氯苯性能的影响

氮氧化物(NO_x)是导致酸雨和光化学烟雾的主要污染物之一,二噁英(PCDD/Fs)则是迄今为止人类已知毒性最强的物质,多污染物协同控制因能大幅降低治理成本而成为新时期大气污染治理的重点。通过水热法制备了MnO₂催化剂,研究了MnO₂催化剂同时催化脱除NO_x与氯苯(CB)的催化性能,同时考察了不同前驱体对催化性能的影响。结果表明:以MnSO₄为前驱体主要形成的是α-MnO₂,其具有最好的同时脱硝脱CB催化性能,并且具有良好的催化稳定性,在长达16 h的连续反应后仍然保持了98%的NO转化率和88%的CB脱除率。α-MnO₂催化剂具有较大的比表面积、较高的表面Mn3+浓度,丰富的表面活性氧物种,使其在中低温下具有优异的氧化还原性能。

EFFECT OF PRECURSORS ON SIMULTANEOUS CATALYTIC REMOVAL OF NITROGEN OXIDES AND CHLOROBENZENE BY MnO2

NO_x is one of the main pollutants that cause acid rain and photochemical smog. PCDD/Fs are the most toxic substance known to mankind so far. The coordinated control of multiple pollutants has become the focus of air pollution control in the new era because it can greatly reduce the cost of treatment. In this paper, the MnO₂ catalyst was prepared by hydrothermal method, and the simultaneous catalytic removal of nitrogen oxides and chlorobenzene was investigated. Meanwhile, the effect of different precursors on the catalytic performance was investigated. The results showed that the main formation of manganese sulfate as the precursor was α-MnO₂, which exhibited the best catalytic performance for catalytic removal of nitrogen oxides and chlorobenzene, and had good catalytic stability. It still maintained 98% of NO conversion and 88% of chlorobenzene conversion after 16 h continuous reaction. The α-MnO₂ had a large specific surface area, a high Mn3+ concentration on the surface, and richer surface active oxygen species, so it exhibited excellent redox performance at medium and low temperatures. Therefore, the α-MnO₂ catalyst with manganese sulfate as the precursor exhibited the best catalytic performance.