Low-cost Mn-Fe/SAPO-34 catalyst from natural ferromanganese ore and lithium-silicon-powder waste for efficient low-temperature NH-SCR removal of NO.

The development of low-temperature selective catalytic reduction of NO with NH (NH-SCR) catalysts is desirable but still challenging. Herein, a low-cost Mn-Fe/SAPO-34 catalyst was successfully synthesized using natural ferromanganese ore (FO) and industrial waste lithium-silicon-powder (LSP) by solid-state ion exchange (SSIE) method, and showed high NH-SCR activity at low temperature range (150-200 °C) with high N selectivity. After loading FO, Mn-O and Fe-O bonds on Mn-Fe/SAPO-34 were weakened, which were beneficial to electron transfer and the oxidation-reduction cycle of SCR. The coexisting of Mn and Fe promoted the dispersion of Fe, resulted in high amounts of O, Mn and Fe which facilitated the adsorption and activization of NH over Mn-Fe/SAPO-34 catalyst. The Brønsted and Lewis acid sites participate in NH-SCR, and the adsorbed nitrate species could quickly react with the adsorbed NH species via the Langmuir-Hinshelwood (L-H) mechanism. The Mn-Fe/SAPO-34 integrated the advantages of low-cost, resource saving and environment friendly, giving a low-carbon and sustainable choice for the industrial application of NO abatement.