Combined poisoning effect of K+ and its counter-ion (Cl− or NO3−) on MnOx/TiO2 catalyst during the low temperature NH3-SCR of NO

•Alkali poisoning is a major concern for low-T NH3-SCR on MnOx/TiO2.•KCl impacts more severely than KNO3 on deNOx activity due to combined poisoning effects.•K+ poisons strong Lewis acid sites of the catalyst regardless of counter-ion.•Cl− inhibits oxygen availability from MnOx.•NO3− strongly affects process selectivity for T>150°C.