Porous polypropylene membrane for CO2 electro-reduction in organic medium

A low-cost porous polypropylene membrane has been employed as the diaphragm for CO2 electro-reduction in H-type electrolysis cell in organic electrolyte. Compared with the commonly used Nafion membrane, porous polypropylene exhibits many advantages, such as low cost, low ionic transport resistance, high Faradaic efficiency, low cell voltage, and high energy efficiency. The ionic transport mechanism in polypropylene membrane has been investigated: owing to the presence of interconnected sponge-like in the membrane, and due to the hydrophobic nature of polypropylene, only organic solution can enter into the pore of the polypropylene membrane. As a consequence, an organic/aqueous liquid–liquid interface is formed on the anode side. During the electrolysis process, H2O is oxidized at the anode. The generated protons transfer through the liquid–liquid interface and diffuse to the cathode to take part in CO2 electro-reduction reaction. Because the cost of polypropylene membrane is cheap, it has a promising perspective in practical utilization.