Turning CO₂ into methane with a blue pigment: results and limits

Copper phthalocyanine achieved up to 79.5% Faradaic efficiency for methane in laboratory conditions.

Oct 19, 2026 0 1

Turning CO₂ into methane with a blue pigment: results and limits

Copper phthalocyanine achieved up to 79.5% Faradaic efficiency for methane in laboratory conditions.

The result

Researchers led by Tohoku University used copper phthalocyanine on a gas-diffusion electrode to electrochemically reduce CO₂ to methane. The 79.5% figure is peak Faradaic efficiency for methane under tested conditions. It is not an electricity-to-fuel energy efficiency figure, nor proof of a positive overall climate balance.

Scaling questions

The team reports a maximum current density of 575 mA/cm² and methane selectivity above 60% for roughly 80 hours at 150 mA/cm². Real deployment requires more evidence on durability, electricity cost, CO₂ capture, gas purification and eventual combustion emissions. Low-emission power is relevant but not a complete climate assessment.