Metal organic frameworks-assisted fabrication of CuO/Cu2O for enhanced selective catalytic reduction of NOx by NH3 at low temperatures.

Porous CuO/Cu2O heterostructure was successfully synthesized through a metal organic frameworks (MOFs)-assisted template method. Tunable production of pure phase CuO and Cu2O could be achieved by regulating the coordination environment of copper. The copper oxides inherited the polyhedral morphology from the Cu MOFs and possessed higher surface area and larger pore volume. Compared with pure CuO and Cu2O, heterostructured CuO/Cu2O displayed remarkably enhanced NH3-SCR de-NOx activity and N2 selectivity in a low temperature range of 170-220 °C. Systematical in situ DRIFT characterization revealed that the NH3-SCR of NOx over CuO/Cu2O heterostructure followed Eley-Rideal (E-R) mechanism, which was greatly improved by the abundant Lewis acid sites, improved O2 adsorption and the synergistic effect between Cu+ and Cu2+. In addition, CuO/Cu2O heterostructure exhibited excellent H2O, SO2, alkali metals, and hydrocarbon durability, indicating its potential use in industrial NH3-SCR of NOx.