For TiO2-based photoanodes, the interfacial coupling between TiO2 and conductive materials (e.g., carbon), plays a vital role in determining the electron transfer efficiency and thus photoelectrical performance. In this paper, we describe a facile approach to effectively engineering the interfacial coupling between reduced graphene oxide (RGO) and TiO2 in well-designed one-dimensional (1D) RGO-wrapped TiO2 nanofibers, which act as ultrafast electron transfer bridges when implanted in photoanodes. The 3-5 nm RGO nanoshells were hybridized with TiO2 nanofibers as an electron donor component via d-p electron orbital overlap between C and Ti atoms, by adopting a thermal reduction at 450 oC. Remarkable photoelectric improvement in term of high photocurrent density by 2.2-fold and ultralow charge transfer resistance (Rct) by 0.2-fold is ascribed to the interfacial charge transfer. Completely reduced RGO in RGO/TiO2 nanofibers was not necessary at the expense of their hydrophilicity, as it led to unexpected isolation in the photoanodes. The thermal reduction temperature of RGO/TiO2 nanofibers was found to be critical, and a maximal photocurrent density could be achieved by 2.7-fold at 530 oC. The excessive RGO/TiO2 nanofibers more than 5 wt % had degrading effect on photoelectrical activity, largely due to the light-block effect and isolation in matrix. This strategy provides new insight for tuning intrinsically chemical and/or physical properties of well-designed semiconductor nanostructures with promising photoactivities in highly efficient photovoltaic devices.

Novel graphene-wrapped TiO<sub>2</sub> nanofibers with effective interfacial coupling as ultrafast electron transfer bridges

248th National Meeting (2014)

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Novel graphene-wrapped TiO2 nanofibers with effective interfacial coupling as ultrafast electron transfer bridges

Novel graphene-wrapped TiO₂ nanofibers with effective interfacial coupling as ultrafast electron transfer bridges