Abstract
Chemical-looping oxidative dehydrogenation(CL-ODH)is a process designed for the conversion of al-kanes into olefins through cyclic redox reactions,eliminating the need for gaseous O2.In this work,we investigated the use of Ca2MnO4-layered perovskites modified with NaNO3 dopants,serving as redox catalysts(also known as oxygen carriers),for the CL-ODH of ethane within a temperature range of 700-780 ℃.Our findings revealed that the incorporation of NaNO3 as a modifier significantly enhanced the selectivity for ethylene generation from Ca2MnO4.At 750 ℃ and a gas hourly space velocity of 1300 h-1,we achieved an ethane conversion up to 68.17％,accompanied by a corresponding ethylene yield of 57.39％.X-ray photoelectron spectroscopy analysis unveiled that the doping NaNO3 onto Ca2MnO4i not only played a role in reducing the oxidation state of Mn ions but also increased the lattice oxygen content of the redox catalyst.Furthermore,formation of NaNO3 shell on the surface of Ca2MnO4 led to a reduction in the concentration of manganese sites and modulated the oxygen-releasing behavior in a step-wise manner.This modulation contributed significantly to the enhanced selectivity for ethylene of the NaNO3-doped Ca2MnO4 catalyst.These findings provide compelling evidence for the potential of Ca2MnO4-layered perovskites as promising redox catalysts in the context of CL-ODH reactions.
基金项目
National Natural Science Foundation of China(22179027)
Natural Science Foundation of Guangxi Province(2021GXNSFAA075063)
Natural Science Foundation of Guangxi Province(2018GXNSFDA281005)
National Key Research and Development Program of China(2017YFE0105500)
Science & Technology Research Project of Guangdong Province(2017A020216009)
NETL
NSTL
万方数据