Insights into high CO-SCR performance of CuCoAlO catalysts derived from LDH/MOFs composites and study of H2O/SO2 and alkali metal resistance

Selective catalytic reduction of NOx with CO technology (CO-SCR) is deemed to be a valid and economical solution for NOx abatement. Currently, developing CO-SCR catalysts with better performance for boosting NOx purification is imperative but still lacking. Moreover, H2O/SO2 and alkali metal poisoning of CO-SCR catalysts are still austere challenges. Herein, we have elaborately designed Cu and Zn modified CoAlO catalysts by heating decomposition of LDH/MOFs composite precursors. The physicochemical property, denitration performance, anti-K, anti-H2O and anti-SO2 poisoning ability of catalyst were systematically investigated. Catalytic tests showed that the CuCoAlO catalyst achieved 99.1% NO conversion at 200 °C, and maintained excellent long-term catalytic stability. The strong synergistic interaction between Co and Cu leads to stronger redox property and abundant surface active oxygen species, and brings the outstanding deNOx performance. Impressively, the CuCoAlO catalyst displayed splendid water and alkali resistance which exhibited great potential in practical application. The catalytic and SO2-deactivation mechanisms were investigated by in situ FTIR spectra and DFT analysis, demonstrating that the nitrates and weak carbonate species are the main intermediates. SO2 hindered the SCR reaction by competing with NO for adsorption sites. This work provides a new strategy for the design and fabrication of low temperature CO–SCR catalysts and will be favorable to academic and practical applications in the future.