Atomic force microscopy resolved semiconductor-electrolyte interface for photocatalytic water splitting
Shaoqiang Su is a PhD student in the department Physics of Complex Fluids. (Co)Supervisors are prof.dr. F.G. Mugele, prof.dr. G. Mul, dr. I. Sîretanu and dr. B.T. Mei from the faculty of Science & Technology.
The semiconductor-electrolyte interface properties can have substantial impacts on the photocatalytic performance of semiconductors. However, they remain unexplored due to the lack of a suitable tool. In this thesis, duale scale atomic force microscopy was developed to resolve the semiconductor-electrolyte interface properties on individual faceted semiconducting nanoparticles in situ and operando with sub-facet resolutions. For the first the time, the facet and pH dependent surface charge/potential, surface photo voltage were determined in electrolytes. Thanks to the the high-resolution advantage of AFM, the atomic surface structures and facet dependent hydration structures were also imaged. It enabled us to corelate the heterogeneous surface structure especially on the wide defect rich regions and narrow atomic steps to the distinct charge behaviours and photo responses. All of the results are unique and crucial for facet-dependent phenomena, such as facet-selective accumulation of photo-generated charge carriers and photo deposition in the photocatalysis field, and organic adsorption and particulate aggregation in the colloidal society.
