Unraveling the role of single-atom metal dopant over CeO2 catalyst in tuning catalytic performance of ethane oxidative dehydrogenation

Abstract

Single-atom metal doped CeO2 (M1@CeO2) catalysts have exhibited better catalytic performance in methane and propane dehydrogenation, which may be applied to ethane dehydrogenation, revealing structure-activity relationship of M1@CeO2 catalysts is of great importance. In this work, DFT + U calculations together with kinetic Monte Carlo simulations were implemented to investigate the oxidative dehydrogenation stage (ODH) in ethane chemical looping-oxidative dehydrogenation (CL-ODH) over thirteen types of M1@CeO2 catalysts (M = Cr, Mn, Fe, Co, Ni, Ga, Mo, Ru, Rh, Pd, In, Ir and Pt). The results show that the doped single-atom metal and its adjacent O atoms act as active sites over four catalysts Rh, Pd, Ir and Pt doped CeO2, while only O atoms act as active sites over other nine catalysts M1@CeO2. Rh1@CeO2 was screened out to perform higher C2H4(g) selectivity of 98.8 % and C2H4(g) formation activity of 8.72×103 s−1 site−1 at 823.15 K with C2H6(g) partial pressure <0.2 bar, which is superior to the previously reported catalysts Pt, Pt3Sn, Pt3Ir, Ni3Mo, Co/g-C3N4 and Rh/ZrO2, and so on. A quantitative and quick descriptor, the binding strength of C2H5* intermediate is proposed to evaluate C2H4(g) formation activity. This study unravels the role of doped single-atom metal over CeO2 catalyst and help rationally design high-efficiency alkane dehydrogenation.