Using Obrando Raman spectroscopy to investigate the conversion of carbon dioxide to ethanol on nanowires

In a study published in the journal China Chemistry Science Led by Professor Pingping Fang (Faculty of Chemistry, Zhejiang University) and Professor Jianfeng Li (Faculty of Chemistry and Chemical Engineering, Xiamen University), the experiments were performed using an Xplora Raman spectrometer with a 50x microscope objective and a 638-nm excitation wavelength of a He–Ne laser.

“Because of the suitable adsorption energy of CO on partially oxidized Ag NWs, it is of great interest to relate ethanol’s high selectivity to CO₂ Electrical conductivity of the partially oxidized active center. It has been shown that Ag catalysts exhibit high CO selectivity₂ electoreduction to CO at low voltage with low H₂ development. CO is an important intermediate for CC coupling, and thus, Ag has the potential to show high selectivity to ethanol products by tuning the CO adsorption energy. This study provides new insight into designing effective catalysts and investigating mechanisms for improving selectivity,” says Fang.

Interestingly, high FE ethanol was obtained on Ag NWs partially oxidized to CO.₂ Electrosorption and EC-SERS process combined with DFT calculation elucidated the mechanisms that make the partially oxidized Ag NWs display high ethanol selectivity. The ethanol FE can reach 85% on partially oxidized Ag NWs at −0.95 V vs RHE. Operando EC-SERS found that high CO coverage can significantly facilitate the formation of ethanol on partially oxidized Ag NWs during CO₂ Electrodoctoral.

DFT calculation results show that the adsorption energy of CO on partially oxidized Ag NWs is higher than that on Cu, and the reaction free energy of coupling CO with *CHO to *COCHO intermediate on partially oxidized Ag NWs is smaller than that on Cu surface, Which explains the high selectivity of ethanol very well.

Therefore, the experiment results, EC-SERS coefficient calculations and DFT together prove that such partially oxidized Ag NWs can provide high ethanol selectivity for CO.₂ Electrodoctoral. These results provide new evidence for the design of Ag-based catalysts for improved ethanol selectivity and mechanism studies.