ZTO nanostructures were
synthesized via hydrothermal method, using a modified version of the
synthesis reported by Li et al.,12 (link) without
the use of a seed layer (in ref (12 (link)) a stainless steel mesh seed-layer is used).Figure S18a shows the schematic of the synthesis
where the precursor concentrations used were 0.020 M SnCl4·5H2O and 0.040 M Zn(CH3COO)2·2H2O. The precursors were separately dissolved in
7.5 mL of Millipore water and were then mixed together. Afterward,
7.5 mL of the surfactant ethylenediamine (EDA) were added, and
the mixture was left stirring for 30 min. Finally 0.240 M NaOH was
added. The precursors were smashed in a mortar before being added
to water to help dissolution. The reagents used were all commercially
available: zinc acetate dihydrate 99.0% (Zn(CH3COO)2·2H2O), sodium hydroxide ≥98% (NaOH),
and ethylenediamine 99% (EDA) from Sigma-Aldrich, tin(IV) chloride
5-hydrate (SnCl4·5H2O) extra pure from
Riedel-de Haën and zinc chloride 98% (ZnCl2) from
Merck.
To study the influence of the zinc precursor, zinc acetate
was replaced by zinc chloride, maintaining the same concentration
of zinc in the solution. Different Zn:Sn ratios (molar concentration)
were studied, namely, 2:1, 1:1, and 1:2. The ratio between H2O and EDA was varied (H2O:EDA, 15:0, 9:6, 8:7, 7.5:7.5,
7:8, 6:9, 0:15), as well as the concentration of NaOH (0.100 M, 0.175
M, 0.240, and 0.350 M). When the solution was ready, it was transferred
into a 45 mL Teflon-lined stainless-steel autoclave, filling 80% of
the total autoclave volume. The mixture was kept in an electric oven
(Thermo Scientific) at 200 °C for 24 h, with a heating ramp of
200 °C/h. The autoclave was cooled to ambient temperature naturally.
The resultant precipitate, comprising the nanostructures, was centrifuged
at 4000 rpm and washed several times with deionized water and isopropyl
alcohol, alternately. The nanostructures were finally dried at 60
°C,
in vacuum, for 2 h, as schematized inFigure S18b .
synthesized via hydrothermal method, using a modified version of the
synthesis reported by Li et al.,12 (link) without
the use of a seed layer (in ref (12 (link)) a stainless steel mesh seed-layer is used).
where the precursor concentrations used were 0.020 M SnCl4·5H2O and 0.040 M Zn(CH3COO)2·2H2O. The precursors were separately dissolved in
7.5 mL of Millipore water and were then mixed together. Afterward,
7.5 mL of the surfactant ethylenediamine (EDA) were added, and
the mixture was left stirring for 30 min. Finally 0.240 M NaOH was
added. The precursors were smashed in a mortar before being added
to water to help dissolution. The reagents used were all commercially
available: zinc acetate dihydrate 99.0% (Zn(CH3COO)2·2H2O), sodium hydroxide ≥98% (NaOH),
and ethylenediamine 99% (EDA) from Sigma-Aldrich, tin(IV) chloride
5-hydrate (SnCl4·5H2O) extra pure from
Riedel-de Haën and zinc chloride 98% (ZnCl2) from
Merck.
To study the influence of the zinc precursor, zinc acetate
was replaced by zinc chloride, maintaining the same concentration
of zinc in the solution. Different Zn:Sn ratios (molar concentration)
were studied, namely, 2:1, 1:1, and 1:2. The ratio between H2O and EDA was varied (H2O:EDA, 15:0, 9:6, 8:7, 7.5:7.5,
7:8, 6:9, 0:15), as well as the concentration of NaOH (0.100 M, 0.175
M, 0.240, and 0.350 M). When the solution was ready, it was transferred
into a 45 mL Teflon-lined stainless-steel autoclave, filling 80% of
the total autoclave volume. The mixture was kept in an electric oven
(Thermo Scientific) at 200 °C for 24 h, with a heating ramp of
200 °C/h. The autoclave was cooled to ambient temperature naturally.
The resultant precipitate, comprising the nanostructures, was centrifuged
at 4000 rpm and washed several times with deionized water and isopropyl
alcohol, alternately. The nanostructures were finally dried at 60
°C,
in vacuum, for 2 h, as schematized in
