cs501733r_si_001.pdf (3.51 MB)
Structure Sensitivity of La2O2CO3 Catalysts in the Oxidative Coupling of Methane
journal contribution
posted on 2015-03-06, 00:00 authored by Yu-Hui Hou, Wei-Chen Han, Wen-Sheng Xia, Hui-Lin WanMethane is the main component of
natural gas and shale gas. It
is chemically stable, and its activation often requires high temperatures,
which lead to its extensive transformation into undesirable products
such as CO and CO2. Thus, the development of efficient
catalysts for the selective transformation of methane represents a
substantial challenge. In this work, we synthesized La2O2CO3 samples with different morphologies (rod-
and plate-shapes) at the nanometer scale. We observed that one of
the rod-shaped samples exhibited the best catalytic properties among
the investigated samples in the oxidative coupling of methane (OCM)
at low temperatures (420–500 °C); in addition, its specific
activity was 20 times greater than that of any of the other rod-shaped
samples. This difference corresponded to the O2-TPD results
and was attributed to the crystallographic facets exposed. Among the
exposed facets, the (110), (12̅0), and (21̅0) facets had
relatively loose atomic configurations that increased the conversion
of methane in the OCM. Moreover, these facets were beneficial to the
formation of the chemisorbed oxygen species and their moderately basic
sites, which improve the selectivity in the OCM.