TY - JOUR
T1 - Integration of Molybdenum-Doped, Hydrogen-Annealed BiVO 4 with Silicon Microwires for Photoelectrochemical Applications
AU - Milbrat, Alexander
AU - Vijselaar, Wouter
AU - Guo, Yuxi
AU - Mei, Bastian
AU - Huskens, Jurriaan
AU - Mul, Guido
N1 - ACS deal
PY - 2019/3/4
Y1 - 2019/3/4
N2 - H-BiVO 4-x :Mo was successfully deposited on microwire-structured silicon substrates, using indium tin oxide (ITO) as an interlayer and BiOI prepared by electrodeposition as precursor. Electrodeposition of BiOI, induced by the electrochemical reduction of p-benzoquinone, appeared to proceed through three stages, being nucleation of particles at the base and bottom of the microwire arrays, followed by rapid (homogeneous) growth, and termination by increasing interfacial resistances. Variations in charge density and morphology as a function of spacing of the microwires are explained by (a) variations in mass transfer limitations, most likely associated with the electrochemical reduction of p-benzoquinone, and (b) inhomogeneity in ITO deposition. Unexpectedly, H-BiVO 4-x :Mo on microwire substrates (4 μm radius, 4 to 20 μm spacing, and 5 to 16 μm length) underperformed compared to H-BiVO 4-x :Mo on flat surfaces in photocatalytic tests employing sulfite (SO 3 2- ) oxidation in a KPi buffer solution at pH 7.0. While we cannot exclude optical effects, or differences in material properties on the nanoscale, we predominantly attribute this to detrimental diffusion limitations of the redox species within the internal volume of the microwire arrays, in agreement with existing literature and the observations regarding the electrodeposition of BiOI. Our results may assist in developing high-efficiency PEC devices.
AB - H-BiVO 4-x :Mo was successfully deposited on microwire-structured silicon substrates, using indium tin oxide (ITO) as an interlayer and BiOI prepared by electrodeposition as precursor. Electrodeposition of BiOI, induced by the electrochemical reduction of p-benzoquinone, appeared to proceed through three stages, being nucleation of particles at the base and bottom of the microwire arrays, followed by rapid (homogeneous) growth, and termination by increasing interfacial resistances. Variations in charge density and morphology as a function of spacing of the microwires are explained by (a) variations in mass transfer limitations, most likely associated with the electrochemical reduction of p-benzoquinone, and (b) inhomogeneity in ITO deposition. Unexpectedly, H-BiVO 4-x :Mo on microwire substrates (4 μm radius, 4 to 20 μm spacing, and 5 to 16 μm length) underperformed compared to H-BiVO 4-x :Mo on flat surfaces in photocatalytic tests employing sulfite (SO 3 2- ) oxidation in a KPi buffer solution at pH 7.0. While we cannot exclude optical effects, or differences in material properties on the nanoscale, we predominantly attribute this to detrimental diffusion limitations of the redox species within the internal volume of the microwire arrays, in agreement with existing literature and the observations regarding the electrodeposition of BiOI. Our results may assist in developing high-efficiency PEC devices.
KW - UT-Hybrid-D
KW - BiVO
KW - PEC devices
KW - Performance
KW - Silicon geometry
KW - Sulfite oxidation
KW - BiOI
UR - http://www.scopus.com/inward/record.url?scp=85062399032&partnerID=8YFLogxK
U2 - 10.1021/acssuschemeng.8b05756
DO - 10.1021/acssuschemeng.8b05756
M3 - Article
AN - SCOPUS:85062399032
VL - 7
SP - 5034
EP - 5044
JO - ACS sustainable chemistry & engineering
JF - ACS sustainable chemistry & engineering
SN - 2168-0485
IS - 5
ER -