NCAFM2023 Programme Booklet

CHARGE STATE OF STEPS ON ANATASE TiO2(101) AT 78 K BY AFM KPFM

Jiuyan Wei, Yasuhiro Sugawara and Yanjun Li

Department of Applied Physics, Osaka University, 565-0871 Japan Email: liyanjun@ap.eng.osaka-u.ac.jp

Steps on anatase TiO 2 (101) surface as the important surface defects strongly influence the catalyst surface. The structures of steps on anatase TiO 2 (101) are complex which are found that step B has stronger charge trapping characteristics [1] [2]. However, the charge state of other steps and their different origin are still unclear. In this work, the structure and charge of different steps on the anatase TiO 2 (101) surface are investigated by AFM/KPFM at 78 K. The property of detail steps may help to understand catalytic reaction and overall materials performance in many applications. The steps on the surface were investigated by simultaneously topographic, CPD and current images using AFM/KPFM as shown in Fig.1. The four steps of A, B, C and D can be clearly obtained in topographic image. We know that the charge states of steps are different in current and CPD images. Step B has lowest CPD and charge trapping property than steps A, C, and D. Step A has the highest CPD and the weakest current. Step C has lower CPD than step D. This study demonstrates how steps charge properties can be used by adsorbates, enhancing catalytic and allowing one to design high-performance transition-metal oxide catalysts.

Fig. 1 Steps on anatase TiO 2 (101) surface by AFM/KPFM at 78 K. (a) Topography. (b) CPD image. (c) Current image. The line profiles of (d-f) correspond to (a-c). The steps are marked by A, B, C and D.

References [1] Gong, Xue-Qing, et al. Nature materials 5.8: 665-670 (2006). [2] Setvin, Martin, et al. Angewandte Chemie International Edition 53.18: 4714-4716 (2014).

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