Simultaneous Generation of Ammonia during Nitrile Waste Gas Purification over a Silver Single-Atom-Doped Ceria Catalyst

This work proposed a waste-to-resourcesolution for purificationof nitrile waste gas via a selective catalytic oxidation reactionon a silver single-atom-doped ceria nanorod. Catalytic elimination of toxic nitrile waste gas is ofgreat significancefor preserving the atmospheric environment, but achieving resourceutilization during its destruction has been less explored. Herein,this study proposed a universal strategy for nitrile waste gas purificationand NH3 generation simultaneously. The developed silversingle-atom-doped ceria nanorod (Ag-1/R-CeO2)was endowed with near complete mineralization and around 90% NH3 yield at 300-350 & DEG;C for the catalytic oxidationof both acetonitrile and acrylonitrile. The introduction of the Agsingle atom created more surface oxygen vacancies, thereby promotingwater activation to form abundant surface hydroxyl groups. As a benefitfrom this, the hydrolysis reaction of nitrile to generate NH3 was accelerated. Meanwhile, the electron transfer effect from theAg atom to Ce and hydroxyl species facilitated NH3 desorption,which inhibited the oxidation of NH3. Moreover, the increasedsurface oxygen vacancies also promoted the mineralization of hydrolysiscarbonaceous intermediates to CO2. In contrast, the Agnanoparticle-modified sample possessed stronger reducibility and NH3 adsorption, leading to the excessive oxidation of NH3 to N-2 and NO x . Thiswork provided a useful guidance for resourceful purification of nitrilewaste gas.

Automated summary

This study proposed a universal strategy for the purification of nitrile waste gas and simultaneous generation of NH3. A silver single-atom-doped ceria nanorod was used for selective catalytic oxidation of the waste gas, resulting in near complete mineralization and high NH3 yield. The introduction of the silver single atom promoted water activation and accelerated the hydrolysis reaction of nitrile to generate NH3.