Regeneration of sulfur-poisoned CeO2 catalysts via in situ treatment from NH3-SCR atmosphere

Ammonia selective catalytic reduction (NH3-SCR) is well utilized for NOx elimination, but the deactivation of SCR catalysts under practical conditions is a headache. Conventional methods for catalyst regeneration include heat treatment and solution leaching, which bear typical drawbacks of high energy cost, long time duration and requirement of off-site regeneration. In the present study, a novel regeneration strategy was proposed to alleviate SO2 poisoned SCR catalyst via in situ treatment under reaction atmosphere. The effects from operation atmosphere, temperature and duration of treatment time on regeneration efficiency were comprehensively investigated. It was confirmed that the ammonia contained in the reaction atmosphere greatly promoted sulfur removal from catalyst surface. Simultaneously, the crucial active sites with good redox property were replenished, which played an essential role in securing activity recovery. The result of present study is expected to provide useful guidance for regeneration of SCR catalysts poisoned by SO2.