Tailoring the mechanochemical interaction between vanadium oxides and zeolite for sulfur-resistant DeNOx catalysts

Abstract

© 2022 Elsevier B.V.Utilizing mechanochemical interactions to fabricate hybrid catalysts composed of two or more materials is an important emerging area in heterogeneous catalysis. Here, we report unusual deactivation of vanadia catalyst derived from mechanical grinding with Al-rich zeolite, initially designed to overcome the ammonium bisulfate poisoning in low-temperature selective catalytic reduction (SCR) of NOx. Various characterizations reveal that mechanical force applied to zeolite imparts mobility to extra-framework AlOx moieties. Some of the diffused AlOx species bound to VOx sites lower reducibility of catalyst, degrading its initial performance. These phenomena are effectively resolved by novel strategy of covering the surface of zeolite with a thin carbon layer, suppressing the diffusion of AlOx moieties during grinding. The hybrid catalyst prepared by tailoring mechanochemical interaction demonstrates superior sulfur resistance in low-temperature (180 °C) SCR operation. Our study critically describes effects of mechanical forces on catalytic properties and efficient modulation of these interactions through surface functionalization.