A new electrocatalytic technology (diagram) is said to be the first to produce methanol from CO2 at ambient temperature and pressure in a commercially viable reactor design. Oxylus Energy (New Haven, Conn.; www.oxylusenergy.com) recently unveiled a 5-cm2 electrolysis cell to demonstrate its electrified CO2-conversion process.
Special modifications to the cobalt phthalocyanine catalyst, developed by professor Hailiang Wang and Oxylus chief technology officer and co-founder Conor Rooney at Yale University’s Energy Science Institute, enable the process to operate at much milder process conditions, but also significantly increase the methanol selectivity of the reaction. “There are no other catalysts that can do low-temperature and low-pressure CO2 electrolysis to methanol,” emphasizes Perry Bakas, CEO and co-founder of Oxylus Energy. The first iteration of the catalyst involved cobalt phthalocyanine being spread over carbon nanotubes, the addition of a microporous layer to the catalytic electrode structure and the amendment of an amine to the cobalt phthalocyanine’s ligands, explains Bakas.
Initial runs showed reaction selectivity for methanol of around 40%, but subsequent kinetic studies have continued to improve upon the Faradaic efficiency of the reaction. The microporous layer greatly enhanced mass transport of CO and increased Faradaic efficiency from 40 to 66%, according to work published last year in Nature Synthesis. “We’ve now achieved well over 80% selectivity of the CO2-to-methanol conversion. We’ve really proven that we can do this at a commercially relevant selectivity,” says Bakas.
Oxylus is now building membrane-electrode assembly reactors around this catalyst. “The reactor is similar to a typical proton-exchange-membrane (PEM) electrolyzer setup, but on the cathode side, there’s a gas-diffusion electrode where the CO2 conversion takes place,” says Bakas. Alongside the launch of the 5-cm2 cell, the team is currently running tests on a 50-cm2 cell.