Combined fast selective reduction using Mn-based catalysts and nonthermal plasma for NOx removal.

In this study, the concept of fast SCR for NO reduction with NH as reducing agent is realized via the combination of nonthermal plasma (NTP) with Mn-based catalyst. Experimental results indicate that 10% wt. Mn-Ce-Ni/TiO possesses better physical and chemical properties of surface, resulting in higher NO removal efficiency if compared with 10% wt. Mn-Ce/TiO and 10% wt. Mn-Ce-Cu/TiO. Mn-Ce-Ni/TiO of 10% wt. achieves 100% NO conversion at 150 °C, while 10% wt. Mn-Ce/TiO and 10% wt. Mn-Ce-Cu/TiO need to be operated at a temperature above 200 °C for 100% NO conversion. However, NO conversion achieved with 10% wt. Mn-Ce-Ni/TiO is significantly reduced as HO and SO are introduced into the SCR system simultaneously. Further, two-stage system (SCR with DBD) is compared with the catalyst-alone for NO conversion and N selectivity. The results indicate that 100% NO conversion can be achieved with two-stage system at 100 °C, while N selectivity reaches 80%. Importantly, NO conversion achieved with two-stage system could maintain >95% in the presence of CH, CO, SO, and HO, indicating that two-stage system has better tolerance for complicated gas composition. Overall, this study demonstrates that combining NTP with Mn-based catalyst is effective in reducing NO emission at a low temperature (≤200 °C) and has good potential for industrial application.