Ni-doped metal-azolate framework-6 derived carbon as a highly active catalyst for CO2 conversion through the CO2 hydrogenation reaction

A profound and accelerated solution towards mitigating atmospheric CO2 levels and converting the CO2 to useful fuels and chemicals, such as CO or CH4, would be to utilize and promote the catalytic CO2 hydrogenation reaction. To optimize this process, high-performance catalysts and favorable conditions must be identified. This study incorporated Ni-doped MAF-6 (containing Zn, N and C) derived carbon-supported catalysts synthesized by in-situ impregnation. By varying the Ni loading amount (1–4 wt.%) and the pyrolysis temperature (600–900 °C), this determined as to how the nanomaterial structures and interactions can tune the reaction performance. Based on BET, PXRD and XPS characterization tests, the carbon structure was porous with highly dispersed and embedded Ni generated by a strong interaction between Ni and Zn-N-C in the MAF-6-derived carbon material, especially as the increasing pyrolysis temperatures evaporated more Zn. From this, CO2 hydrogenation catalytic tests were carried out at 500–800 °C and 100 mL min−1 flow at a H2: CO2 ratio of 3:1. Based on the key structural and material properties, the MAF-64Ni,600 catalyst (i.e., 4 wt.% Ni loading, 600 °C pyrolysis) proved to be optimal, displaying 59% CO2 conversion and 100% CO selectivity at 650 °C. Most of the catalysts formed no CH4 due to the low loading of Ni.