Is it possible to convert carbon dioxide into a solid at low cost?
This article in the press cites CO2 has been converted  into Carbon at relative low temperature.

The research team led by RMIT University in Melbourne, Australia, have developed a new technique that can efficiently convert CO2 from a gas into solid particles of carbon.


To date, CO2 has only been converted into a solid at extremely high temperatures, making it industrially unviable.
By using liquid metals as a catalyst, we’ve shown it’s possible to turn the gas back into carbon at room temperature, in a process that’s efficient and scalable.
While more research needs to be done, it’s a crucial first step to delivering solid storage of carbon.

The study is published in Nature Communications. They used cerium oxyde as catalyst to reduce the temperature of the reaction.

... which facilitates the electrochemical reduction of CO2 to layered
solid carbonaceous species, at a low onset potential of −310 mV vs
CO2/C

All these CO2 sequestration issues are under investigation and will be implemented in the coming years by energy companies.

Esrafilzadeh, D., Zavabeti, A., Jalili, R. et al. (2019): &quot;Room temperature CO2 reduction to solid carbon species on liquid metals featuring atomically thin ceria interfaces.&quot; Nat Commun 10, 865. https://doi.org/10.1038/s41467-019-08824-8