Electrochemical oxidation of ethylene glycol on TiO2-supported platinum single-atom catalyst into valuable chemicals in alkaline media

Abstract

The application of single-atom catalysts (SACs) receives excellent attention in producing fine chemicals. SACs demonstrate higher activity, selectivity, stability and are more economical. Herein we designed and successfully synthesized an electrochemical catalyst consisting of Pt single atoms on titanium oxide support (PtSAC/TiO2) via hydrothermal assisted co-precipitation method, which is simple, fast, and efficient. The high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image and FT- EXAFS spectra disclose that Pt atoms are well dispersed and show no Pt–Pt coordination. We are the first to apply SACs for partial oxidation of Ethylene glycol (EGO) using PtSAC/TiO2. The strong metal support interaction (SMSI) between Pt and TiO2 and the availability of identical Pt active sites enhanced catalytic selectivity of PtSAC/TiO2. These help EG oxidation on PtSAC/TiO2 to produce glycolate and formate selectively. The higher surface contacts between PtSAC and EG lead to an improved catalytic performance towards EGO. Our stability tests demonstrated that PtSAC/TiO2 showed a slower current decay rate and higher oxidation current density, thus providing better electrocatalytic activity and stability. Hence, PtSAC/TiO2 led to higher reactivity and provided a higher current density response. The as-synthesized PtSAC/TiO2 catalyst exhibits an excellent Faradaic efficiency of 99.7 % and remarkable stability, with a very minimal current drop within 12 h in an alkaline solution.