Abundant Ce Ions in Au-CeO Nanosheets to Enhance CO Electroreduction Performance.

The electroreduction of CO to CO provides a potential way to solve the environmental problems caused by excess fossil fuel utilization. Loading transition metals on metal oxides is an efficient strategy for CO electroreduction as well as for reducing metal usage. However, it needs a great potential to overcome the energy barrier to increase CO selectivity. This paper describes how 8.7 wt% gold nanoparticles (NPs) loaded on CeO nanosheets (NSs) with high Ce concentration effectively decrease the overpotential for CO electroreduction. The 3.6 nm gold NPs on CeO NSs containing 47.3% Ce achieve CO faradaic efficiency of 90.1% at -0.5 V in 0.1 m KHCO solution. Furthermore, the CO electroreduction activity shows a strong relationship with the fractions of Ce on Au-CeO NSs, which has never been reported. In situ surface-enhanced infrared absorption spectroscopy shows that Au-CeO NSs with high Ce concentration promote CO activation and *COOH formation. Theoretical calculations also indicate that the improved performance is attributed to the enhanced *COOH formation on Au-CeO NSs with high Ce fraction.