Semiconductor-mediated photocatalysis often benefits from the use of a metal co-catalyst, which promotes the electron-hole separation across the Schottky barrier at the interface. Photodeposition of the metal onto the semiconductor presents an opportunity to create an intimate interface between the metal and the semiconductor. In aqueous conditions, pH serves as a tunable parameter affecting the semiconductor surface, solvent interactions, and chemical potential of the metal ions in solution. In this study, we systematically explore the effect of pH on the growth of photodeposited Ag nanoparticles using several titania-based semiconductor substrates: TiO2 rutile, TiO2 anatase, SrTiO3, and BaTiO3. Photodeposition efficiency was monitored by Atomic Absorption, UV-visible Absorption, X-ray Fluorescence Spectroscopies, X-ray Diffraction, and Transmission Electron Microscopy. Total Ag photodeposition becomes suppressed as pH is lowered, although the quantitative trends differ for different substrates. In combination with the results of zeta-potential measurements, we discuss the findings from the point of view of pH-dependent surface charging effect.

Semiconductor-Independent effect of pH on the growth of photodeposited silver nanoparticles

2019 Spring National Meeting

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