TY - JOUR
T1 - Single Ir Atoms Anchored on Ordered Mesoporous WO3 Are Highly Efficient for the Selective Catalytic Reduction of NO with CO under Oxygen-rich Conditions
AU - Jiang, Ruihuan
AU - Liu, Shaomian
AU - Li, Liang
AU - Ji, Yongjun
AU - Li, Huifang
AU - Guo, Xiangfeng
AU - Jia, Lihua
AU - Zhong, Ziyi
AU - Su, Fabing
N1 - Publisher Copyright:
© 2021 Wiley-VCH GmbH
PY - 2021/4/9
Y1 - 2021/4/9
N2 - Under oxygen-rich conditions, achieving a selective and efficient reduction of NO by CO is always challenging. Here, we report the synthesis of the catalyst consisting of single Ir atoms anchored on mesoporous WO3 (denoted as Ir1/m-WO3) using a facile template method followed by wet impregnation. X-ray diffraction and transmission electron microscope studies indicated that the Ir atoms were distributed uniformly on the internal surface of m-WO3. When tested for the reduction of NO by CO, the Ir1/m-WO3 catalyst with a low Ir loading of 0.28 wt % exhibited excellent catalytic performance in the presence of 2 vol % O2 (volume ratio of CO to O2 being 1 : 10), achieving a NO conversion of 73 % and N2 selectivity of 100 % at 350 °C. In particular, its turnover frequency (TOF) value reached 0.30 s−1 at 200 °C, which is six times higher than that of the catalyst with Ir nanoparticles supported on mesoporous WO3 (0.05 s−1). The superior catalytic performance of Ir1/m-WO3 is attributed to the formation of the isolated Ir atoms and the more newly generated Ir-WO3 interfaces that can promote the adsorption and activation of NO, and the presence of accessible mesopores in m-WO3 that facilitates the mass transfer of NO and CO. This study brings a new fundamental understanding of active sites in Ir-based catalysts for the CO+NO reaction and provides a new way to the design and synthesis of single-atom catalysts, especially precious metal catalysts for emissions control.
AB - Under oxygen-rich conditions, achieving a selective and efficient reduction of NO by CO is always challenging. Here, we report the synthesis of the catalyst consisting of single Ir atoms anchored on mesoporous WO3 (denoted as Ir1/m-WO3) using a facile template method followed by wet impregnation. X-ray diffraction and transmission electron microscope studies indicated that the Ir atoms were distributed uniformly on the internal surface of m-WO3. When tested for the reduction of NO by CO, the Ir1/m-WO3 catalyst with a low Ir loading of 0.28 wt % exhibited excellent catalytic performance in the presence of 2 vol % O2 (volume ratio of CO to O2 being 1 : 10), achieving a NO conversion of 73 % and N2 selectivity of 100 % at 350 °C. In particular, its turnover frequency (TOF) value reached 0.30 s−1 at 200 °C, which is six times higher than that of the catalyst with Ir nanoparticles supported on mesoporous WO3 (0.05 s−1). The superior catalytic performance of Ir1/m-WO3 is attributed to the formation of the isolated Ir atoms and the more newly generated Ir-WO3 interfaces that can promote the adsorption and activation of NO, and the presence of accessible mesopores in m-WO3 that facilitates the mass transfer of NO and CO. This study brings a new fundamental understanding of active sites in Ir-based catalysts for the CO+NO reaction and provides a new way to the design and synthesis of single-atom catalysts, especially precious metal catalysts for emissions control.
KW - CO+NO reaction
KW - Ir single-atom
KW - ordered mesoporous WO
KW - oxygen-rich condition
UR - http://www.scopus.com/inward/record.url?scp=85100832005&partnerID=8YFLogxK
U2 - 10.1002/cctc.202001784
DO - 10.1002/cctc.202001784
M3 - 文章
AN - SCOPUS:85100832005
SN - 1867-3880
VL - 13
SP - 1834
EP - 1846
JO - ChemCatChem
JF - ChemCatChem
IS - 7
ER -