Preparation of nano Cu-Mo2C interface supported on ordered mesoporous biochar of ultrahigh surface area for reverse water gas shift reaction

Abstract

Abstract High conversion rate and selectivity are challenges for CO 2 utilization through catalytic reverse water gas shift (RWGS) reaction. Herein, a novel mesoporous biochar (MB) supported Cu-Mo 2 C nano-interface was prepared by consecutive physical activation of coconut shells followed by carbothermal hydrogen reduction of bimetal. As compared with traditional carbon materials, this MB exhibited ultra-high specific surface area (2693 m 2 g –1 ) and mesopore volume of mesopore (0.81 cm 3 g –1 ) with a narrow distribution (2–5 nm), responsible for the high dispersion of binary Cu-Mo 2 C sites, CO 2 adsorption and mass transfer in the reaction system. Moderate carbothermal reduction led to the sufficient reduction of Mo ion with carbon matrix of MB and dispersive growth of nano Cu-Mo 2 C binary sites (~ 6.1 nm) on the surface of MB. Cu + species were formed from Cu 0 via electron transfer and showed high dispersion with simultaneous boosted bimetal loading due to the strong interaction between nano Mo 2 C and Cu. These were advantageous to the intrinsic activity and stability of the Cu-Mo 2 C binary sites and their accessibility to the reactant molecules. Under the RWGS reaction conditions of 500 °C, atmospheric pressure, and 300,000 ml/g/h gas hour space velocity, the CO 2 conversion rate over Cu-Mo 2 C/MB reached 27.74 × 10 –5 mol CO2 /g cat /s at very low H 2 partial pressure, which was more than twice that over traditional carbon supported Cu-Mo 2 C catalysts. In addition, this catalyst exhibited 99.08% CO selectivity and high stability for more than 50 h without a decrease in activity and selectivity. This study offers a new development strategy and a promising candidate for industrial RWGS. Graphical Abstract