Production of doped nanoparticles, and use of same

Abstract

A process for producing doped nanoparticles, in particular for N-doped nanoparticles, includes a hydrothermal process using an organic nitrogen-containing compound or a mineral acid having at least one nitrogen atom. In particular, the photocatalytically active particles produced are characterized by a particularly high activity even in visible light.

Claims

1. A process for producing doped nanoparticles, which comprises: a) provision of a composition comprising: at least one hydrolysable metal compound, at least one compound having at least one hydroxyl group, and at least one mineral acid comprising at least one nitrogen atom; b) hydrothermal treatment of the composition to form doped nanoparticles, wherein the nanoparticles are doped with nitrogen from the at least one mineral acid; and c) isolation of the doped nanoparticles.

2. The process as claimed in claim 1, wherein the hydrolysable compound is a compound of the formula
MX.sub.n where M is selected from the group consisting of Mg, B, Al, Ga, In, Si, Ge, Sn, Pb, Y, Ti, Zr, V, Nb, Ta, Mo, W, Fe, Cu, Ag, Zn, Cd, Ce and La and n corresponds to the valence of the metal and X is a hydrolysable group.

3. The process as claimed in claim 1, wherein the at least one compound having at least one hydroxyl group has a boiling point below 200° C.

4. The process as claimed in claim 1, wherein the at least one compound having at least one hydroxyl group is a lower aliphatic alcohol.

5. The process as claimed in claim 1, wherein the mineral acid comprising at least one nitrogen atom is nitric acid.

6. The process as claimed in claim 5, wherein the nitric acid catalyzes hydrolysis of the hydrolysable metal compound.

7. The process as claimed in claim 5, wherein a molar ratio of nitrogen to the metal of the hydrolysable metal compound is from 0.05:1 to 0.7:1.

8. The process as claimed in claim 1, wherein the nanoparticles are photocatalytically active nanoparticles.

9. The process as claimed in claim 1, wherein the nanoparticles are photocatalytically active nanoparticles which are photocatalytically active at wavelengths above 400 nm.

10. The process as claimed in claim 1, wherein the composition does not contain any organic compound comprising at least one nitrogen atom.

11. The process as claimed in claim 1, wherein a molar ratio of nitrogen to the metal of the hydrolysable metal compound is from 0.001:1 to 0.4:1.

12. A process for producing metallic structures, which comprises: (a) application of an initiator composition to a substrate, where the composition comprises photocatalytically active nanoparticles produced as in claim 1 as initiator; (b) application of a precursor composition comprising at least one precursor compound for a metal layer to the substrate; and (c) reduction of the precursor compound to the metal by action of electromagnetic radiation on the initiator.

13. A process for producing metallic structures, comprising: application of an initiator composition to a substrate, where the composition comprises photocatalytically active nanoparticles produced as claimed in claim 5 as initiator; application of a precursor composition comprising at least one precursor compound for a metal layer to the substrate; and reduction of the precursor compound to the metal by action of electromagnetic radiation on the initiator.

14. A process for producing metallic structures, comprising: application of an initiator composition to a substrate, where the composition comprises photocatalytically active nanoparticles produced as claimed in claim 6 as initiator; application of a precursor composition comprising at least one precursor compound for a metal layer to the substrate; and reduction of the precursor compound to the metal by action of electromagnetic radiation on the initiator.

15. A method comprising depositing nanoparticles produced as in claim 5 to form a metallic layer.

Description

(1) The working examples are shown schematically in the figures. Identical reference symbols in the individual figures denote identical elements or elements having the same functions or corresponding to one another in respect of their functions. In detail, the figures show:

BRIEF DESCRIPTION OF THE DRAWINGS

(2) FIG. 1 transmission electron micrograph of nanoparticles according to the invention;

(3) FIG. 2 transmission electron micrograph of nanoparticles according to the invention;

(4) FIG. 3 photograph of an illumination.

DETAILED DESCRIPTION OF THE DRAWINGS

(5) 1. Synthesis of N-Doped Tio.sub.2

(6) N-doped TiO.sub.2 nanoparticles were produced by means of the solvothermal process. 24.26 g of titanium isopropoxide were dissolved in 26.36 g of 1-propanol. 1.58 g of HNO.sub.3 (68%) were added to 5 g of 1-propanol and added to the titanium tetraisopropoxide solution while stirring. 2.56 g of water were dissolved in 10 g of 1-propanol and slowly added dropwise to the titanium tetraisopropoxide solution. The solution was stirred for 20 minutes, transferred into Teflon vessels for the autoclave and heated to 225° C. for 1 hour. The heating rate was 5 K/min. After cooling, the supernatant solution was decanted off and the solvent was removed from the residue on a rotary evaporator. Yield: 7.5 g of a brown solid, particle size: 11.8 nm. FIGS. 1 and 2 show transmission electron micrographs of the particles obtained.

2. SYNTHESIS OF C/N-DOPED TIO.SUB.2

(7) C/N-doped TiO.sub.2 nanoparticles were produced by means of a solvothermal process. 24.26 g of titanium isopropoxide were dissolved in 26.36 g of 1-propanol. 1.58 g of HNO.sub.3 (68%) were added to 5 g of 1-propanol and added to the titanium tetraisopropoxide solution while stirring. 2.56 g of water and 0.3 g of glucose were dissolved in 10 g of 1-propanol and slowly added dropwise to the titanium tetraisopropoxide solution. The solution was stirred for 20 minutes, transferred into Teflon vessels for the autoclave and heated to 225° C. for 1 hour. The heating rate was 5 K/min. After cooling, the supernatant solution was decanted off and the solvent was removed from the residue on a rotary evaporator. Yield: 7.89 g of a brown solid, particle size: 13.5 nm

3. PRODUCTION OF A SOL FOR DIP COATING

(8) 0.3-0.9 g of particles (as per No. 1 or No. 2) were dispersed in 4 g of 0.1 M HNO.sub.3. 0.67 ml of 3,6,9-trioxadecanoic acid per 1 g of particles was added. After stirring for 10 minutes, 46 g of 2-isopropoxyethanol were added.

4. COATING BY MEANS OF DIP COATING

(9) Glass substrates were coated by means of dip coating. A cleaned glass substrate was dipped into the sol as per No. 3. The drawing speed was 1 mm/s−5 mm/s. Optically transparent layers were obtained.

5. WAVELENGTH-DEPENDENT PHOTOMETALLIZATION

(10) 0.5 ml of a mixture of a silver nitrate solution (0.845 g of AgNO.sub.3 in 10 g of distilled water) and a TRIS solution (1.284 g of tris(hydroxymethyl)aminomethane in 10 g of distilled water) was applied to a coated microscope slide (as per No. 4). The solution was illuminated for 5 minutes with light from a 1000 W Hg/Xe lamp which had been split by means of a monochromator. Silver deposits were observed up to wavelengths of 435 nm.

6. PHOTOMETALLIZATION AT 405 NM

(11) 0.5 ml of a mixture of a silver nitrate solution (0.845 g of AgNO.sub.3 in 10 g of distilled water) and a TRIS solution (1.284 g of tris(hydroxymethyl)aminomethane in 10 g of distilled water) was applied to a coated microscope slide (as per No. 4). The solution was illuminated with light from a 405 nm LED. Conductive layers are obtained after only 3 minutes.

7. PHOTOMETALLIZATION THROUGH A GLASS PLATE

(12) 0.5 ml of a mixture of a silver nitrate solution (0.845 g AgNO.sub.3 in 10 g of distilled water) and a TRIS solution (1.284 g of tris(hydroxymethyl)aminomethane in 10 g of distilled water) was applied to a coated microscope slide (as per No. 4 with particles according to No. 1), and this was covered with a second microscope slide and illuminated for 10 s with light from a 1000 W Hg/Xe lamp. Conductive layers were obtained.

8. DIRECT LASER INSCRIPTION

(13) 0.5 ml of a mixture of a silver nitrate solution (0.845 g of AgNO.sub.3 in 10 g of distilled water) and a TRIS solution (1.284 g of tris(hydroxymethyl)aminomethane in 10 g of distilled water) was applied to a coated microscope slide (as per No. 4 with particles according to No. 1). A grid structure was inscribed on this by means of a laser (376 nm). The silver structure obtained is conductive.

9. MASK ILLUMINATION

(14) The silver complex solution was introduced between a coated substrate (as per No. 4 with particles according to No. 1) and a mask composed of fused silica. The solution was illuminated through the mask by means of a 1000 W Hg/Xe lamp. The illumination time until conductive structures (5 μm line width) are obtained is 1 minute (for undoped TiO.sub.2: 3 minutes).

(15) FIG. 3 shows an optical micrograph of a metallic structure obtained after illumination for 1 minute. The structure has a width of 4.79 μm.

(16) The undoped particles were produced as described in DE102010052032A1.

(17) 48.53 of Ti(O—i—Pr).sub.4 were added to 52.73 g of 1-PrOH (n-propanol). A solution composed of hydrochloric acid (37%, 3.34 g) and 10.00 g of 1-PrOH was slowly added dropwise to this solution. A mixture of 4.02 g of H.sub.2O and 20.00 g of 1-PrOH was then added dropwise to this solution. The solution obtained may be slightly yellowish and was introduced into a pressure digestion vessel (about 130 g). The solution was treated for 2.5 hours at 210° C. in this vessel.

(18) The mixture was decanted and the particles obtained were transferred to a flask and the solvent was removed under reduced pressure at 40° C. on a rotary evaporator.

(19) The particles were then applied in an analogous way to the substrates.