Family of biomass-derived Ni and Ni-Mn catalysts of CO2 methanation

CO2 utilization nowadays is one of the most important challenges posed by global warming. CO2 conversion to methane is considered as a stage of the Power-to-X technology that uses green electricity for hydrogen production. Sustainable utilization of agricultural wastes is also a hot topic of the responsible consumption and production. In this work rice husk (RH) was used to produce Ni-based catalysts of CO2 methanation. We suggested different treatments of RH for the synthesis of various catalyst supports. The purity of the support was found to be a crucial parameter determining the catalyst structure, activity, and selectivity. Sulfur, phosphorous, alkali and alkaline-earth metal impurities decreased the CO2 conversion and methane selectivity, while promotion with manganese strongly enhanced the catalyst efficiency. Up to 86 % CO2 conversion and 100 % methane selectivity were observed even at 250 degrees C over the Mn-promoted Ni-based catalysts supported on amorphous silica and purified RH ash. The stability of the catalyst depended on its specific surface area and chemical composition. The oxide-based supports with the highest specific surface areas were the most stable and active in CO2 conversion. The RH-derived samples showed a promising activity at rather low operation temperatures and can be considered as green, cheap, and stable catalysts for the Power-to-X technology.

Automated summary

CO2 utilization is a crucial challenge in combating global warming. This study focuses on the conversion of CO2 to methane using Ni-based catalysts supported on rice husk. The purity of the support plays a crucial role in determining the catalyst's structure, activity, and selectivity.