Selective catalytic reduction; Nitrogen oxides removal; Catalyst regeneration; Thermoporometry; Catalyst pore landscape

Controlling carbon and nitrogen chemistry is essential for human life and civilization. In particular, high-temperature combustion of carbon fuels in the air results in the formation of ecotoxic carbon and nitrogen oxides (NOx). Specifically, NOx needs to be removed from the flue gases of electric power stations. The selective catalyst reduction (SCR) systems support the deNOx (NOx removal) process; however, surface deposits deactivate the SCR system while operating. Moreover, the surface texture is damaged during the exploitation. We show here how this damage reveals itself in the pore landscape of the commercial SCR catalysts. In particular, for the first time, we showed how this could be assessed by a combination of thermoporometry (TPM) and gas physisorption. Accordingly, a correlation between the assessed quality of the pore landscape and the catalyst activity was determined and discussed. We designed a broad collection of new innovative regeneration procedures, which appear to be robust and selective methods for removing surface poisons. The optimal regeneration scheme fully restored the catalyst activity.