Enhanced production of C2-C4 alkanes from syngas via the metal sulfides-support interaction over Ni-MoS2/Ce1-xLaxO2-δ
Direct conversion of syngas for selective production of light alkanes (C2-C4), driven by the demand for renewable petrochemicals and fuels, is promising but challenging due to the low selectivity. This study reports construction of an interaction among the metal (Ni-Mo) sulfides and support (Ce1-xLaxO2-δ) serves to appreciably enhance the target alkane selectivity without a severe loss of catalytic activity or stability. Characterization measurements (e.g., XPS, TEM-EDX, TPR, TPR-S, TPS, CO-TPD, Raman and in-situ DRIFT of CO adsorption) demonstrates the interaction between Ni and MoS2 generated the active NiMoS phase, which facilitated the C-C chain growth, achieving up to 75.9% selectivity of C2-C4 alkanes at a CO conversion of 25.1%. Monolayer dispersed sulfide species (NiMoVOxSy-II) in strong interaction with the support, generated via the low-temperature sulfidation, was favorable for the CO adsorption and delivered higher conversion rates relative to the conditional multi-stacked metal sulfides. This work establishes tuning the interaction between the metal sulfides and support as an alternative means to selectively produce C2-C4 alkanes in the direct conversion of syngas.