Abatement of Nitrogen Oxides via Selective Catalytic Reduction over Ce1-W1Atom-Pair Sites

Environmentally benign CeO2-WO3/TiO2catalysts are promisingalternatives to commercial toxic V2O5-WO3/TiO2for controlling NOxemission viaselective catalytic reduction (SCR), but the insufficient catalytic activity of CeO2-WO3/TiO2catalysts is one of the obstacles in their applications because of a lack of anin-depth understanding of the CeO2-WO3interactions. Herein, we design a Ce1-W1/TiO2model catalyst by anchoring Ce1-W1atom pairs on anatase TiO2(001) toinvestigate the synergy between Ce and W in SCR. A series of characterizationscombined with density functional theory calculations andin situdiffuse-reflectanceinfrared Fourier-transform experiments reveal that there exists a strong electronicinteraction within Ce1-W1atom pairs, leading to a much better SCR performance ofCe1-W1/TiO2compared with that of Ce1/TiO2and W1/TiO2. The Ce1-W1synergynot only shifts down the lowest unoccupied states of Ce1near the Fermi level, thusenhancing the abilities in adsorbing and oxidizing NH3but also makes the frontierorbital electrons of W1delocalized, thus accelerating the activation of O2. The deepinsight of the Ce-W synergy may assist in the design and development of efficient catalysts with an SCR activity as high as or evenhigher than V2O5-WO3/TiO2

Automated summary

This study investigates the synergy between Ce and W in selective catalytic reduction (SCR) by designing a Ce1-W1/TiO2 model catalyst. The strong electronic interaction within Ce1-W1 atom pairs is found to enhance the SCR performance of Ce1-W1/TiO2 catalysts.