Improved electrochemical reduction of CO 2 to syngas with a highly exfoliated Ti 3 C 2 T x MXene-gold composite.

Transforming carbon dioxide (CO 2 ) into valuable chemicals via electroreduction presents a sustainable and viable approach to mitigating excess CO 2 in the atmosphere. This report provides fresh insights into the design of a new titanium-based MXene composite as a catalyst for the efficient conversion of CO 2 in a safe aqueous medium. Despite its excellent electrocatalytic activity towards CO 2 reduction and high selectivity for CO production, the high cost of Au and the decline in catalytic activity on a larger scale hinder its large-scale CO 2 conversion applications. In this research, we have successfully prepared an Au/Ti 3 C 2 T x composite and tested its catalytic activity in the electrochemical CO 2 reduction reaction (ECRR). The as-prepared composite features strong interactions between gold atoms and the MXene support, achieved through the formation of metal-oxygen/carbon bonds. The Au/Ti 3 C 2 T x electrode demonstrated a significant current density of 17.3 mA cm -2 at a potential of -0.42 V vs. RHE, in a CO 2 saturated atmosphere (faradaic efficiency: CO = 48.3% and H 2 = 25.6%). Nyquist plots further indicated a reduction in the charge-transfer resistance of the Au/Ti 3 C 2 T x layer, signifying rapid charge transfer between the Au and Ti 3 C 2 T x . Furthermore, it is known that liquid crossover through the Gas Diffusion Electrode (GDE) significantly improves CO 2 diffusion to catalyst active sites, thereby enhancing CO 2 conversion efficiency. The goal of this work is to design an interface between metal and MXene so that CO 2 can be electroreduced to fuels and other useful chemical compounds with great selectivity.