Tunable functional groups on MXene regulating the catalytic property of anchored cobalt phthalocyanine for electrochemical CO2 reduction

The regulation of the intermediate adsorption strength is the key for boosting the catalytic performance, while it is still a challenge to achieve this in a facile manner. Herein, CoPc complex was anchored on an MXene support bearing different terminal groups (-F or -OH) to systematically investigate the effect of the terminal groups of the MXene support on the performance of the electrochemical CO2 reduction reaction (ECRR). By forming Co-O axial coordination, the anchoring of CoPc was facilitated and the electronic states of Co were tuned. As a result, CoPc/MXene-OH shows an impressive faradaic efficiency for CO formation (FECO) of 92.4%, higher than that of CoPc/MXene-F (84.0%) under the same conditions. Mechanistic explorations show that the excellent performance is attributed to the electron-donating property of -OH enriching the electron density of Co, which optimizes the binding strength for intermediates and therefore boosts the ECRR performance. The simple synthesis method opens up a new avenue for regulating the electronic states of active sites and further the intermediate adsorption strength for efficient electrocatalyst design.