Synergistic interplay of dual active sites on spinel ZnAl2O4 for syngas conversion

The urgent need for efficiency improvement in the oxide-zeolite bifunctional syngas-to-hydrocarbon catalysis necessitates in-depth mechanistic insights into this reaction, especially for the initial syngas conversion over the oxide component, which remains poor. Herein, we comprehensively investigated syngas conversion over a representative ZnAl 2 O 4 spinel oxide with state-of-the-art solid-state NMR technologies. Notably, specific surface dual active sites for syngas activation with –Al IV –OH···Zn III – structure were unambiguously identified. More importantly, the dynamic evolution of the reaction intermediates and active sites during the reaction process was elaborated at atomic level by a series of double resonance and multi-dimensional correlation NMR experiments. In combination with in situ spectroscopic characterizations, we revealed the full cycle of the formate-methoxy-based pathway for the syngas-to-methanol conversion via synergistic interplay of the dual active sites. The in-depth atomic-level understanding of the catalytic mechanism will be beneficial to further rational design of high-performance catalysts for syngas conversion.