Method for producing nano-silver powder or nano-gold powder

Abstract

The invention relates to a method for preparing nano-silver powders or nano-gold powders. In a single cell, metallic silver or an gold electrode is processed through anodic oxidation, inert conducting material is used as a cathode, room-temperature ionic liquid containing silver salt or gold salt is used as electrolysing solution, the electrolysis is executed under direct current, and the nano-silver powders or the nano-gold powders are obtained around the cathode; wherein, the silver salt is AgBF4; the gold salt is Au (PPh3) Cl or Au (PPh3) Br; the room-temperature ionic liquid is one of [bmim]BF4, [bmim]PF6, [emim]BF4, and [hmim]BF4. In the method, the metallic silver or gold is used as a sacrificial anode, the nano-silver powders and the nano-gold powders can be produced directly through electrolysis, the technology is simple, the cost is low, and the method is suitable for industrialized production. The room-temperature ionic liquid is used as an electrolytic dissolvent, the ionic liquid performs a role of not only a dissolvent but also a dispersant and a stabilizing agent, and nano-metal is easy to obtain, compared with water solution; compared with organic solvent, the room-temperature ionic liquid is safer and more environment-protecting.

Description

technical field

[0001] The invention relates to a method for preparing nano-silver powder or nano-gold powder, in particular to a method for preparing nano-silver powder or nano-gold powder by using an electrochemical sacrificial anode method in room temperature ionic liquid containing silver salt or gold salt. Background technique

[0002] Nano-metal materials not only have the basic properties of bulk metals, but also exhibit electrical, magnetic, optical, thermal and mechanical properties that bulk metals do not have, and have broad application prospects.

[0003] At present, the chemical methods for preparing nano-metals mainly include sol-gel method, microemulsion method, template method, chemical reduction method, electrochemical method and so on. Among them, the electrochemical method has the following characteristics: no toxic or dangerous chemical oxidants and reducing agents are needed; "electrons" themselves are clean reagents; in the reaction system, the two proc...

Examples

Embodiment 1

[0033] Embodiment one: a kind of method for preparing nano-silver powder

[0034] In a 25ml single-chamber electrolytic cell, add 0.065g of silver tetrafluoroborate (AgBF 4 ) and 5.0ml ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF 4), the silver salt is fully dissolved at 80°C, and the filtrate is obtained after filtration; the metal silver (12mm×40mm, purity is 99.9%) is used as the anode, the platinum wire is the cathode, and the filtrate is the electrolyte. 100W), the cell voltage is 2.0V, and the current density is 0.5A / dm 2 , the pole distance is 5mm, the electrolysis temperature is 20-40°C, there is soot-like powder precipitated near the cathode, stop the electrolysis after 2 hours, filter the electrolyte suspension, and wash the soot-like powder with absolute ethanol (5.0ml each time) for 5-5~ 8 times, dry naturally to get nano-silver powder. After electron microscope scanning, the morphology of the obtained product is as follows: figure 1 sho...

Embodiment 2

[0035] Embodiment two: a kind of method for preparing nano-silver powder

[0036] In a 25ml single-chamber electrolytic cell, add 0.15g of silver tetrafluoroborate (AgBF 4 ) and 5.0ml ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF 6 ), the silver salt is fully dissolved at 80°C, and the filtrate is obtained after filtration; the metal silver (12mm×40mm, purity is 99.9%) is used as the anode, the tungsten wire is the cathode, and the filtrate is the electrolyte. 100W), the cell voltage is 2.0V, and the current density is 0.27A / dm 2 , the pole distance is 15mm, the electrolysis temperature is 20-50°C, soot-like powder is precipitated near the cathode, stop the electrolysis after 3 hours, filter, wash the soot-like powder with acetone (5.0ml each time) for 5-8 times, and dry naturally. Get nano silver powder.

Embodiment 3

[0037] Embodiment three: a kind of method for preparing nano-silver powder

[0038] In a 25ml single-chamber electrolytic cell, add 0.56g of silver tetrafluoroborate (AgBF 4 ) and 5.0ml ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim]BF 4 ), the silver salt is fully dissolved at 80°C, and the filtrate is obtained after filtration; the anode is the metal silver (12mm × 40mm, purity 99.9%), the silver sheet is the cathode, and the filtrate is the electrolyte, which is electrolyzed by direct current, ultrasonic (ultrasonic power 100W), the cell voltage is 1.5V, and the current density is 11.0A / dm 2 , the pole distance is 45mm, the electrolysis temperature is 20-28°C, soot-like powder is precipitated near the cathode, stop the electrolysis after 0.5h, filter, wash the soot-like powder with absolute ethanol (5.0ml each time) for 5-8 times, and naturally Dry to get nanometer silver powder.

technical field

[0001] The invention relates to a method for preparing nano-silver powder or nano-gold powder, in particular to a method for preparing nano-silver powder or nano-gold powder by using an electrochemical sacrificial anode method in room temperature ionic liquid containing silver salt or gold salt. Background technique

[0002] Nano-metal materials not only have the basic properties of bulk metals, but also exhibit electrical, magnetic, optical, thermal and mechanical properties that bulk metals do not have, and have broad application prospects.

[0003] At present, the chemical methods for preparing nano-metals mainly include sol-gel method, microemulsion method, template method, chemical reduction method, electrochemical method and so on. Among them, the electrochemical method has the following characteristics: no toxic or dangerous chemical oxidants and reducing agents are needed; "electrons" themselves are clean reagents; in the reaction system, the two proc...

Examples

Embodiment 1

[0033] Embodiment one: a kind of method for preparing nano-silver powder

[0034] In a 25ml single-chamber electrolytic cell, add 0.065g of silver tetrafluoroborate (AgBF 4 ) and 5.0ml ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF 4), the silver salt is fully dissolved at 80°C, and the filtrate is obtained after filtration; the metal silver (12mm×40mm, purity is 99.9%) is used as the anode, the platinum wire is the cathode, and the filtrate is the electrolyte. 100W), the cell voltage is 2.0V, and the current density is 0.5A / dm 2 , the pole distance is 5mm, the electrolysis temperature is 20-40°C, there is soot-like powder precipitated near the cathode, stop the electrolysis after 2 hours, filter the electrolyte suspension, and wash the soot-like powder with absolute ethanol (5.0ml each time) for 5-5~ 8 times, dry naturally to get nano-silver powder. After electron microscope scanning, the morphology of the obtained product is as follows: figure 1 sho...

Embodiment 2

[0035] Embodiment two: a kind of method for preparing nano-silver powder

[0036] In a 25ml single-chamber electrolytic cell, add 0.15g of silver tetrafluoroborate (AgBF 4 ) and 5.0ml ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF 6 ), the silver salt is fully dissolved at 80°C, and the filtrate is obtained after filtration; the metal silver (12mm×40mm, purity is 99.9%) is used as the anode, the tungsten wire is the cathode, and the filtrate is the electrolyte. 100W), the cell voltage is 2.0V, and the current density is 0.27A / dm 2 , the pole distance is 15mm, the electrolysis temperature is 20-50°C, soot-like powder is precipitated near the cathode, stop the electrolysis after 3 hours, filter, wash the soot-like powder with acetone (5.0ml each time) for 5-8 times, and dry naturally. Get nano silver powder.

Embodiment 3

[0037] Embodiment three: a kind of method for preparing nano-silver powder

[0038] In a 25ml single-chamber electrolytic cell, add 0.56g of silver tetrafluoroborate (AgBF 4 ) and 5.0ml ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim]BF 4 ), the silver salt is fully dissolved at 80°C, and the filtrate is obtained after filtration; the anode is the metal silver (12mm × 40mm, purity 99.9%), the silver sheet is the cathode, and the filtrate is the electrolyte, which is electrolyzed by direct current, ultrasonic (ultrasonic power 100W), the cell voltage is 1.5V, and the current density is 11.0A / dm 2 , the pole distance is 45mm, the electrolysis temperature is 20-28°C, soot-like powder is precipitated near the cathode, stop the electrolysis after 0.5h, filter, wash the soot-like powder with absolute ethanol (5.0ml each time) for 5-8 times, and naturally Dry to get nanometer silver powder.

Images