Selective Catalytic Reduction of NO(x) over Perovskite-Based Catalysts Using C(x)H(y)(O(z)), H(2) and CO as Reducing Agents—A Review of the Latest Developments

Selective catalytic reduction (SCR) is probably the most widespread process for limiting NO(x) emissions under lean conditions (O(2) excess) and, in addition to the currently used NH(3) or urea as a reducing agent, many other alternative reductants could be more promising, such as C(x)H(y)/C(x)H(y)O(z), H(2) and CO. Different catalysts have been used thus far for NO(x) abatement from mobile (automotive) and stationary (fossil fuel combustion plants) sources, however, perovskites demand considerable attention, partly due to their versatility to combine and incorporate various chemical elements in their lattice that favor deNO(x) catalysis. In this work, the C(x)H(y)/C(x)H(y)O(z)(−), H(2)(−), and CO-SCR of NO(x) on perovskite-based catalysts is reviewed, with particular emphasis on the role of the reducing agent nature and perovskite composition. An effort has also been made to further discuss the correlation between the physicochemical properties of the perovskite-based catalysts and their deNO(x) activity. Proposed kinetic models are presented as well, that delve deeper into deNO(x) mechanisms over perovskite-based catalysts and potentially pave the way for further improving their deNO(x) efficiency.