Electrochemical performance of oxygen-containing vacancy TiO2-CNT support Pt single-atom electrocatalyst
In order to reduce the Pt loading and atom utilization of Pt-supported catalysts,TiO2-CNT composite support was prepared from carboxylated multi-walled carbon nanotubes(MWCNT)and tetrabutyl titanate via sol-gel method,and its surface was introduced a large number of oxygen vacancy(OV)defects by high temperature heat treatment.An electrocatalyst Pt SA/TiO2(OV)-CNT anchored by a composite support with oxygen vacancy defects was then prepared by deposition-precipitation of Pt single-atom(Pt SA)on TiO2(OV)-CNT,characterized by XRD,electron paramagnetic resonance spectroscopy(EPR),HAADF-STEM and XPS,and evaluated by standard three-port electrolytic cell for its electrochemical performance.The results showed that oxygen vacancy defects were successfully introduced onto TiO2-CNT and Pt SA was anchered in the TiO2(OV)-CNT lattice,with charge transfer between the two forming strong metal-support interactions.Pt SA/TiO2(OV)-CNT exhibited a half-wave potential of 0.804 V,a mass activity(MA)of 451.24 A/g(Pt),and a Tafel slope of 63.75 mV/dec at 0.90 V.During oxygen reduction(ORR)operation for 10000 s,the normalized current decreased by 17%,showing better ORR dynamics.Pt SA/TiO2(OV)-CNT showed high catalytic activity with lower Pt loading(mass fraction 1.13%),due to the strong anchoring effect of oxygen vacancy on Pt SA and the protective effect of TiO2 film on CNT.
万方数据
