Performance Exploration of Ni-Doped MoS2 in CO2 Hydrogenation to Methanol

The preparation of methanol chemicals through CO2 and H-2 gas is a positive measure to achieve carbon neutrality. However, developing catalysts with high selectivity remains a challenge due to the irreversible side reaction of reverse water gas shift (RWGS), and the low-temperature characteristics of CO2 hydrogenation to methanol. In-plane sulfur vacancies of MoS2 can be the catalytic active sites for CH3OH formation, but the edge vacancies are more inclined to the occurrence of methane. Therefore, MoS2 and a series of MoS2/Ni-x and MoS2/Co-x catalysts doped with different amounts are prepared by a hydrothermal method. A variety of microscopic characterizations indicate that Ni and Co doping can form NiS2 and CoS2, the existence of these substances can prevent CO2 and H-2 from contacting the edge S vacancies of MoS2, and the selectivity of the main product is improved. DFT calculation illustrates that the larger range of orbital hybridization between Ni and MoS2 leads to CO2 activation and the active hydrogen is more prone to surface migration. Under optimized preparation conditions, MoS2/Ni-0.2 exhibits relatively good methanol selectivity. Therefore, this strategy of improving methanol selectivity through metal doping has reference significance for the subsequent research and development of such catalysts.

Automated summary

Preparation of methanol chemicals from CO2 and H-2 gas is a positive step towards achieving carbon neutrality. However, developing catalysts with high selectivity is challenging due to the side reaction of RWGS and low-temperature characteristics of CO2 hydrogenation. Doping MoS2 with Ni and Co can prevent contact between CO2 and H-2 and enhance the selectivity of the main product, CH3OH. This strategy of metal doping has reference significance for future catalyst research and development.