Sunlight and LEDs are being harnessed by a European consortium to convert carbon dioxide and green hydrogen into methane gas, methanol liquid fuel and other clean energy forms.

A photonics device under development by the SPOTLIGHT consortium is intended to process up to one megaton of CO2 annually to complement existing large-scale carbon capture and utilization processes. Worldwide deployment of the scheme could result in conversion of 2.7 billion tons of CO2 per year into useful chemical fuels.

The process is based on the Sabatier reaction for methane production from green hydrogen and CO2, and on the reverse water gas shift mechanism for carbon monoxide synthesis as a starting material for methanol production.

The photonic device will comprise a transparent flow reactor, optimized for light incoupling in the catalyst bed. Secondary solar optics will concentrate natural sunlight and project it onto the reactor, and an energy efficient LED light source will ensure continuous 24/7 operation.

The system will rely on plasmonic catalysts capable of absorbing the entire solar spectrum. The space-time-yield achieved to date with these catalysts in the Sabatier and reverse water gas shift process is over 104 times higher than for conventional semiconductor catalysts. This makes the concept technically feasible for scale up without excessive land use and with reduced capital expenditures.