Natural gas as a relatively cleaner fuel has gained widespread use in industrial and domestic sectors. However, some countries are short of natural gas and rich in other energies (such as coal and biomass resources), which renders it essential to develop the technology for production of synthetic natural gas (SNG) as a substitute. SNG production relies on catalytic methanation of syngas to methane. MoS2-based catalysts have been studied in the methanation reaction due to the high capability for sulfur tolerance and flexibility in conversion of syngas with a wide range of H2/CO ratios. The existing researches associated with MoS2 system focus on support effect, the dispersion and the sulfuration degree of the molybdenum oxide precursor, the catalytic role of MoS2 in sulfur-resistant methanation haven’t been studied to any significant extent. In this paper, a strategy based on NH4+ intercalation is proposed for synthesis of MoS2 with controllable morphology and contents of edges. A series of ex- and in situ characterizations (including XRD, TEM, SEM, TG-DTG, Raman, N2-physisorption, in situ FT-IR spectroscopy and CHNS elemental analysis) are used to explore the correlation between catalyst characteristics and catalytic response. A linear relationship between the CO conversion rate and the edge site quantity over unsupported MoS2 catalysts revealed that the active site was MoS2-edge. And the NO-IR spectra indicated that the activity was dependent on the content of S-edge. A slight decrease of CO conversion in the long-term stability evaluation can be linked to carbon deposition and a loss of active components on the basis of Raman and elemental analysis of the spent catalysts. This study established the intercalation of NH4+ into the MoS2 layers as an effective method to tune the edge sites and catalytic activity in the sulfur resistant methanation of syngas, which can broaden the application of MoS2 in other fields.

Tuning the edge sites of MoS2 and catalytic performance in sulfur-resistant methanation of syngas

2019 Fall National Meeting

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