Improved electrochemical reduction of CO to syngas with a highly exfoliated TiCT MXene-gold composite.

Transforming carbon dioxide (CO) into valuable chemicals electroreduction presents a sustainable and viable approach to mitigating excess CO 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 in a safe aqueous medium. Despite its excellent electrocatalytic activity towards CO 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 conversion applications. In this research, we have successfully prepared an Au/TiCT composite and tested its catalytic activity in the electrochemical CO 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/TiCT electrode demonstrated a significant current density of 17.3 mA cm at a potential of -0.42 V RHE, in a CO saturated atmosphere (faradaic efficiency: CO = 48.3% and H = 25.6%). Nyquist plots further indicated a reduction in the charge-transfer resistance of the Au/TiCT layer, signifying rapid charge transfer between the Au and TiCT. Furthermore, it is known that liquid crossover through the Gas Diffusion Electrode (GDE) significantly improves CO diffusion to catalyst active sites, thereby enhancing CO conversion efficiency. The goal of this work is to design an interface between metal and MXene so that CO can be electroreduced to fuels and other useful chemical compounds with great selectivity.