Regulation Lattice Oxygen Mobility via Dual Single Atoms for Simultaneously Enhancing VOC Oxidation and NOx Reduction

Abstract

Synergistic catalytic removal of multipollutants (e.g., volatile organic compound (VOC) oxidation and nitrogen oxide (NO_x) reduction) is highly demanded due to the increasingly strict emission standards. The prevention of the key reactive intermediate species nitrite excessive oxidation over the supported noble-metal catalysts, rather than the traditional low-efficiency transition metal oxide catalysts, remains a great challenge. Herein, a sound strategy of Pd single atoms saturated with acidic transition element ligands is proposed. The coexistence of Pd and V dual single atoms strengthens the adsorption of reactants, while synergistic interaction between dual atoms and surface oxygen weakens activation of lattice oxygen, thus significantly reducing the overoxidation of nitrite. Meanwhile, the neutralization of the active Pd and inert V sites results in a rational decrease in the redox property of Pd and an obvious increase in that of V. The Pd₁V₁/CeO₂ dual single-atom catalyst achieves 90% conversion of NO_x and toluene at 238 and 230 °C and has a large temperature window (>150 °C) for NO_x reduction. This research makes a breakthrough in the development of efficient supported noble-/transition-metal dual single-atom catalysts for VOC and NO_x simultaneous purification.