Eco‐Friendly Synthesis of Cobalt Phthalocyanine for High‐Efficiency CO2${\rm CO}_{2}$ Electroreduction

We report a sustainable and cost-effective synthesis of cobalt phthalocyanine (CoPc) using low-impact solvents and a streamlined purification procedure, achieving an 85% yield with limited waste generation, as indicated by an environmental factor (E-factor) of 18.6. This route provides an eco-friendly approach to producing a molecular electrocatalyst for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msub><mml:mi>CO</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:annotation>${\rm CO}_{2}$</mml:annotation></mml:semantics> </mml:math> reduction. The catalytic activity of the synthesized CoPc is validated by its integration into a gas diffusion electrode with carbon nanotube supports, exhibiting methanol production with a Faradaic efficiency up to 12%, matching the values reached with the conventionally synthesized counterparts. Notably, under high loading (micrometric crystallites of CoPc), <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msub><mml:mi>CO</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:annotation>${\rm CO}_{2}$</mml:annotation></mml:semantics> </mml:math> -to-CO conversion reached 65%, in fair alignment with literature benchmarks. Our work shows that green synthesis can yield high-performance catalysts for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msub><mml:mi>CO</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:annotation>${\rm CO}_{2}$</mml:annotation></mml:semantics> </mml:math> electrochemical reduction ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>CO</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>RR</mml:mi></mml:mrow> <mml:annotation>${\rm CO}_{2}{\rm RR}$</mml:annotation></mml:semantics> </mml:math> ), enabling sustainable methanol production.