Inhibition of CO oxidation over Cu-Mn-Ce-O composite catalyst in the presence of dry powder fire extinguishing agent: Mechanism investigation and mitigation strategy

The effects of typical dry powder fire extinguishing agents (DPFEA) on the CO oxidation catalysts were carried out. Cu-Mn-Ce-O composite catalyst (CuMn/Ce) for CO oxidation in loose contact with two typical components of DPFEA (NH4H2PO4 and NaHCO3) was tested to evaluate the performance of CO removal. The CO catalytic activities mixed by NaHCO3 are worse than those mixed by NH4H2PO4 at the same mixing ratios, which may be caused by the lower temperature range of NaHCO3 decomposition and the masked catalyst surfaces by CO2 and H2O released by NaHCO3. Further, the NaHCO3 resistance approach was proposed by introducing rare earth metal dopants (La, Sm and Ho) or coupling an alkaline sorbent (LiOH). Among all rare earth metal dopants, Sm is most appropriate for enhanced NaHCO3 resistance of CuMn/Ce catalyst. And 20 wt% LiOH-CuMn/Ce shows the best capacity for NaHCO3 resistance, as evidenced by the excellent CO catalytic performance similar to pure CuMn/Ce.