pH-dependence in facet-selective photo-deposition of metals and metal oxides on semiconductor particles

Igor  Sîretanu; YuXi Guo; Bastian Timo Mei; Xiaowei Li; Hongwei Huang; Guido  Mul; Friedrich Gunther Mugele

pH-dependence in facet-selective photo-deposition of metals and metal oxides on semiconductor particles

Igor Sîretanu, YuXi Guo, Bastian Timo Mei, Xiaowei Li, Hongwei Huang, Guido Mul, Friedrich Gunther Mugele

Research output: Contribution to conference › Poster

Abstract

Abstract: Facet-engineering and the deposition of co-catalysts lead to improvement in efficiency of semiconductors in photocatalytic applications. While facet-based charge separation is a known phenomenon and it is reported for a range of semiconductors, there is still a limited understanding of it and the mechanism behind remain elusive. Moreover, the proposed simplistic mechanism based on an offset of the valence band and conduction band of different facets is debated. Here, we show that facet-selective, photo-induced reductive or oxidative deposition of co-catalysts onto plate-like bismuth-oxy-bromide (BiOBr) nanoparticles is strongly pH-dependent. High resolution atomic force microscopy and spectroscopy measurements demonstrate that the effect of pH is caused by a reversal of the surface charge of the 001 facets upon increasing the pH from 3 to 9 (isoelectric point 5), while the side facets remain (increasingly) negatively-charged. We propose a different mechanism and we suggest that differences in surface charge/band bending that vary for different surface orientations is the dominant element causing selective charge transport between different facets and metal-oxide deposition

Original language	English
Publication status	Published - 22 Oct 2018
Event	Liquids@Interfaces 2018 - Bordeaux, France Duration: 22 Oct 2018 → 25 Oct 2018 https://lai2018.sciencesconf.org/

Conference

Conference	Liquids@Interfaces 2018
Abbreviated title	LAI 2018
Country	France
City	Bordeaux
Period	22/10/18 → 25/10/18
Internet address	https://lai2018.sciencesconf.org/

Fingerprint Dive into the research topics of 'pH-dependence in facet-selective photo-deposition of metals and metal oxides on semiconductor particles'. Together they form a unique fingerprint.

Cite this

Sîretanu, I., Guo, Y., Mei, B. T., Li, X., Huang, H., Mul, G., & Mugele, F. G. (2018). pH-dependence in facet-selective photo-deposition of metals and metal oxides on semiconductor particles. Poster session presented at Liquids@Interfaces 2018, Bordeaux, France.

@conference{edbc50796e36401196588b96cb0bb10c,

title = "pH-dependence in facet-selective photo-deposition of metals and metal oxides on semiconductor particles",

abstract = "Abstract: Facet-engineering and the deposition of co-catalysts lead to improvement in efficiency of semiconductors in photocatalytic applications. While facet-based charge separation is a known phenomenon and it is reported for a range of semiconductors, there is still a limited understanding of it and the mechanism behind remain elusive. Moreover, the proposed simplistic mechanism based on an offset of the valence band and conduction band of different facets is debated. Here, we show that facet-selective, photo-induced reductive or oxidative deposition of co-catalysts onto plate-like bismuth-oxy-bromide (BiOBr) nanoparticles is strongly pH-dependent. High resolution atomic force microscopy and spectroscopy measurements demonstrate that the effect of pH is caused by a reversal of the surface charge of the 001 facets upon increasing the pH from 3 to 9 (isoelectric point 5), while the side facets remain (increasingly) negatively-charged. We propose a different mechanism and we suggest that differences in surface charge/band bending that vary for different surface orientations is the dominant element causing selective charge transport between different facets and metal-oxide deposition",

author = "Igor S{\^i}retanu and YuXi Guo and Mei, {Bastian Timo} and Xiaowei Li and Hongwei Huang and Guido Mul and Mugele, {Friedrich Gunther}",

year = "2018",

month = "10",

day = "22",

language = "English",

note = "Liquids@Interfaces 2018, LAI 2018 ; Conference date: 22-10-2018 Through 25-10-2018",

url = "https://lai2018.sciencesconf.org/",

}

TY - CONF

T1 - pH-dependence in facet-selective photo-deposition of metals and metal oxides on semiconductor particles

AU - Sîretanu, Igor

AU - Guo, YuXi

AU - Mei, Bastian Timo

AU - Li, Xiaowei

AU - Huang, Hongwei

AU - Mul, Guido

AU - Mugele, Friedrich Gunther

PY - 2018/10/22

Y1 - 2018/10/22

N2 - Abstract: Facet-engineering and the deposition of co-catalysts lead to improvement in efficiency of semiconductors in photocatalytic applications. While facet-based charge separation is a known phenomenon and it is reported for a range of semiconductors, there is still a limited understanding of it and the mechanism behind remain elusive. Moreover, the proposed simplistic mechanism based on an offset of the valence band and conduction band of different facets is debated. Here, we show that facet-selective, photo-induced reductive or oxidative deposition of co-catalysts onto plate-like bismuth-oxy-bromide (BiOBr) nanoparticles is strongly pH-dependent. High resolution atomic force microscopy and spectroscopy measurements demonstrate that the effect of pH is caused by a reversal of the surface charge of the 001 facets upon increasing the pH from 3 to 9 (isoelectric point 5), while the side facets remain (increasingly) negatively-charged. We propose a different mechanism and we suggest that differences in surface charge/band bending that vary for different surface orientations is the dominant element causing selective charge transport between different facets and metal-oxide deposition

AB - Abstract: Facet-engineering and the deposition of co-catalysts lead to improvement in efficiency of semiconductors in photocatalytic applications. While facet-based charge separation is a known phenomenon and it is reported for a range of semiconductors, there is still a limited understanding of it and the mechanism behind remain elusive. Moreover, the proposed simplistic mechanism based on an offset of the valence band and conduction band of different facets is debated. Here, we show that facet-selective, photo-induced reductive or oxidative deposition of co-catalysts onto plate-like bismuth-oxy-bromide (BiOBr) nanoparticles is strongly pH-dependent. High resolution atomic force microscopy and spectroscopy measurements demonstrate that the effect of pH is caused by a reversal of the surface charge of the 001 facets upon increasing the pH from 3 to 9 (isoelectric point 5), while the side facets remain (increasingly) negatively-charged. We propose a different mechanism and we suggest that differences in surface charge/band bending that vary for different surface orientations is the dominant element causing selective charge transport between different facets and metal-oxide deposition

M3 - Poster

ER -