Optimization and comprehensive mechanism of environment-friendly bimetal oxides catalysts for efficient removal of NO in ultra-low temperature flue gas

•Using urea as reductant can bypass the dehydrogenation rate-limiting step in SCR.•The binary UT-USCR catalysts can effectively purify NOx at ultra-low temperature.•The specific synergistic path between CuOx and MnOx on binary catalyst was revealed.•KOH promoted NO removal at ultra-low temperature by enhancing the NO chemisorption.•The UT-USCR catalyst is a novel SCR catalyst that does not require the acid sites.