Cu-Containing Polyoxotitanate Cluster as a Catalyst Precursor for Understanding the Importance of Cu(II)–TiOx Interface on Selective Catalytic Reduction of NO

The promoting effect of the interface between metal and TiOx structure has been widely recognized in heterogeneous catalysis. However, in-depth understanding at molecular level is a grand challenge due to the complex structural parameters in heterogeneous metal catalysts. Herein, using the Cu-containing polyoxotitanate as the precursor, a CuTiOx/Al2O3 catalyst with well-defined Cu(II)–TiOx interface was synthesized. Such a catalyst inherits the interfacial structure of Cu–O–TiOx in Ti4O(OEt)15(CuCl), eliminating the interference of multi-composition and multi-valence state. When applied in the representative reaction of NH3 selective catalytic reduction of NO (NH3-SCR), the CuTiOx/Al2O3 catalyst provided a higher deNOx activity than Cu/Al2O3 with isolated Cu(II). Mechanism studies demonstrated that the Cu(II)–TiOx interface facilities the adsorption and activation of O2, which effectively enhances the oxidation of NO to NO2 while inhibiting the formation of nitrite and nitrite species and inducing the occurrence of fast-SCR. This study provides a novel strategy for building model catalysts and studying the catalytic mechanism of complex systems.