PTFE nanocoating on Cu nanoparticles through dry processing to enhance electrochemical conversion of CO towards multi-carbon products

Polymer modified copper (Cu) catalysts have demonstrated an increased production of multi-carbon (C 2+ ) products during the electrochemical CO 2 reduction reaction (CO 2 RR). Herein, a solvent-free processing method has been developed to cover commercial Cu nanoparticles with a porous nanocoating of polytetrafluoroethylene (PTFE) that greatly improved the production of C 2+ products. The PTFE coating created a large interfacial surface area that facilitated the transport of CO 2 to the solid-liquid-gas interface. The optimal catalyst achieved a faradaic efficiency of 78% for C 2+ products and a notably large C 2+ to C 1 product ratio of ∼13 at current densities ranging from 400 to 500 mA cm −2 . In comparison, catalysts prepared by a conventional solvent-based method only achieved a faradaic efficiency of 56% for C 2+ products and a small C 2+ to C 1 product ratio of ∼2 in the same current density range. Density functional theory (DFT) calculations suggested that the physisorbed PTFE coating on Cu catalysts plays a more significant role than the most frequently studied chemisorbed PTFE. The physisorbed PTFE is predicted to increase the binding energy of CO intermediates on Cu and lower the activation energy for C-C coupling steps, leading to significantly higher C 2+ product selectivity of the Cu catalysts. Solvent-free synthesis of porous PTFE thin film coated Cu nanocomposite for selective multi-carbon production from electrochemical CO 2 reduction.