CN104785776B

CN104785776B - Surface cleaning method for silver nanoparticle with sodium borohydride aqueous solution

Info

Publication number: CN104785776B
Application number: CN201510236949.6A
Authority: CN
Inventors: 李超禹; 李剑锋
Original assignee: Xiamen University
Current assignee: Xiamen University
Priority date: 2015-05-11
Filing date: 2015-05-11
Publication date: 2017-02-08
Anticipated expiration: 2035-05-11
Also published as: CN104785776A

Abstract

The invention relates to a surface cleaning method for silver nanoparticle with sodium borohydride aqueous solution, and relates to surface treatment of silver nanoparticle. The surface cleaning method for silver nanoparticle with sodium borohydride aqueous solution is simple, easy to operate and is provided under the premise that the structure surface appearance and the following application of the silver nanoparticle are not being influenced, and the odium borohydride solution serves as detergent. The surface cleaning method for silver nanoparticle with sodium borohydride aqueous solution comprises the steps that 1 the silver nanoparticle solution is prepared; 2 treating on the silver nanoparticle solution is conducted with sodium borohydride solution; 3 the surface cleaning on Raman substrate of silver nanoparticle is conducted through the sodium borohydride solution. The sodium borohydride solution can effectively remove the oxidization species and the organic impurity on the surface of the sodium borohydride solution and cannot influence the structure of the silver nanoparticle. The time is short, the operation is simple, and the decomposition product of the sodium borohydride solution is borate which belongs to weak absorption species, so that influence on following experiment is avoided; the sodium borohydride solution is low in cost, cleaning treatment on the silver nanoparticle can be conducted, and the cyclic utilization performance is good.

Description

A kind of method that surface cleaning is carried out to Nano silver grain with sodium borohydride aqueous solution

Technical field

The present invention relates to the surface treatment of Nano silver grain, especially relate to one kind with sodium borohydride aqueous solution to silver nanoparticle The method that particle carries out surface cleaning.

Background technology

Developing rapidly with nanotechnology, synthesis and performance study to noble metal nano particles are more deep, especially It is silver nanostructured, because it is in the dispersion relation of visible light wave range, has relatively other noble metals (gold, copper, platinum, etc.) Higher optical property.But silver nanostructured while there is high optical activity, be still subject to its easily oxidation, pollution Limit it is impossible to widely be used in actual applications.According to thermodynamic analysis in physical chemistry, even if in extremely low oxygen The precipitation of silver ion, under Gas content, in silver nanoparticle colloidal sol, still can occur, after silver ion separates out, absorption is in silver nanostructured table Face, then affected by sulfide, oxygen in experimental situation, ultimately generate one layer of sulfide/oxide skin(coating).

Firstly, because the band gap of sulfide/oxide narrower (～1.2eV), absorb in visible light wave range strong, can make and it The photon that surface interacts is absorbed, and as dielectric layer, so that local electromagnetic field is reduced, and optical activity occurs greatly to decline Subtract；Secondly, this sulfide/oxide layer can suppress testing molecule in the absorption on its surface, hinders chemical bonding process, in spectrum Learn in research, so that Chemical enhancement mechanism is suppressed.Therefore, if one kind can be found effective cleaning is carried out to silver nanostructured surface Method, it will be silver nanostructured spectroscopy, optical electrical catalysis application be greatly improved.But in existing method All existing defects, such as in wet chemical synthesis, to have the surface protectant of strong absorption, cover on silver nanostructured surface The molecule of one layer strong absorption, to reach the effect of protection silver surface.But, just because of the presence of the surface protectant of strong absorption, Hinder its application in next step experiment.So be badly in need of one kind both surface will not be impacted, again can be with effective cleaning The method on surface.

Content of the invention

The purpose of the present invention aims to deficiency present in said method, provides and is not affecting silver nanostructured surface On the premise of pattern and subsequent applications, with sodium borohydride solution as cleaning agent, one kind simple to operation is with sodium borohydride water The method that solution carries out surface cleaning to Nano silver grain.

The present invention comprises the following steps：

1) prepare silver nano-particle solution；

2) using sodium borohydride solution, silver nano-particle solution is processed；

3) surface cleaning to Nano silver grain Raman substrate for the sodium borohydride solution.

In step 1) in, the concrete grammar of described preparation silver nano-particle solution can be：In silver perchlorate solution, respectively Add sodium citrate and ice NaBH₄, with ultra-pure water dilution, then after mix with silver perchlorate, add ascorbic acid to react, obtain Silver nano-particle solution；

Silver perchlorate solution, sodium citrate, ice NaBH₄Mol ratio can be 1.05: 2.12: 0.96；Described Vitamin C The ultimate density of acid can be 1.87mM；The time of described reaction can be 2h；Nano silver grain in gained silver nano-particle solution Particle diameter can be 30～100nm.

In step 2) in, the concrete grammar that described use sodium borohydride solution is processed to silver nano-particle solution can For：By sodium borohydride solution add step 1) gained silver nano-particle solution in, using ultra-violet absorption spectrum technology, silver is received The Spectral Extinction of rice corpuscles solution carries out in-situ characterization before treatment afterwards, and result shows, silver nano-particle solution after treatment, disappears Spectrum narrows, and intensity becomes strong, and peak position occurs blue shift, this is because the reason nominal price oxide species of silver surface are reduced； Silver nano-particle solution after before processing is centrifuged and is dripped sample on silicon chip, then pattern is carried out to both with scanning electron microscope Characterize it was demonstrated that sodium borohydride solution can effectively reduce the oxide species on Nano silver grain surface, and will not be to nanoparticle Pattern impacts；The ultimate density of described sodium borohydride solution can be 1～10mM.

In step 3) in, the concrete grammar of the surface cleaning to Nano silver grain Raman substrate for the described sodium borohydride solution can For：By step 2) process after 52nm silver nano-particle solution centrifuge washing after drop on silicon chip, then drip 10mM pyridine molten Liquid, tests Raman spectrum；In addition, by step 2) process after silver nano-particle solution centrifuge washing after drop on silicon chip, use After 0.1M sodium borohydride solution processes surface, then with 10mM pyridine solution rinse, remove sodium borohydride solution, re-test Raman light Spectrum；, it can be found that before processing, spectrally more impurity peaks in both Raman spectral characteristics of contrast, including silver oxide, no The Raman peaks such as setting carbon, but after sodium borohydride solution is processed, the signal of only pyridine occurs, and spectral signature substantially, does not have The interference at other magazine peaks, and after processing, the Raman signal of pyridine is remarkably reinforced.Show that sodium borohydride solution can effectively go Except the oxide in silver nanoparticle Raman substrate and impurity, and the enhancer of Raman substrate can be effectively improved.

Compared with traditional method, the present invention has the advantages that following outstanding and technique effect：

1) sodium borohydride solution used in the present invention can effectively remove the oxide species on Nano silver grain surface, have Machine thing impurity, and nano grain of silver minor structure will not be impacted；

2) method used herein, the time is short, simple to operate, and the catabolite of sodium borohydride solution is boric acid Salt, belongs to weakly stable species, and subsequent experimental will not be impacted；

3) sodium borohydride solution used in the present invention, cheap, can repeat Nano silver grain is cleaned Process, recycle performance good.

Brief description

Fig. 1 be step 1) in synthesis 52nm particle diameter Nano silver grain scanning electron microscope (SEM) photograph, in FIG, scale is 300nm.

Fig. 2 is step 2) in the Nano silver grain of 52nm particle diameter the scanning electron microscope after being processed with sodium borohydride solution Figure, in fig. 2, scale is 300nm.

Fig. 3 is step 2) in the Nano silver grain colloidal sol of 52nm particle diameter after carrying out before processing with sodium borohydride solution Ultraviolet-visible absorption spectroscopy, after curve a is process, before curve b is process.

Fig. 4 be step 3) in 0.1M sodium borohydride solution to the surface cleaning before processing of Nano silver grain Raman substrate after, 10mM pyridine adsorption contrasts in suprabasil Raman spectrum.

Specific embodiment

Following examples will combine accompanying drawing, and the invention will be further described.

Embodiment 1：The 52nm particle diameter silver nano-particle solution of synthesis, it concretely comprises the following steps：

In the silver perchlorate solution of 1.05mM, it is separately added into 2.12mM sodium citrate and 0.96mM ice NaBH₄Molten Liquid, is slowly added dropwise, and along with being stirred vigorously, stand-by after 2h.After more above-mentioned silver sol being diluted 214 times with ultra-pure water, with After 1.07mM silver perchlorate, the mixing of 1.27mM sodium citrate solution, add the ascorbic acid that ultimate density is 1.87mM, react 2h Afterwards, finally obtain the silver nano-particle solution of 52nm, assume brown.Take 1.5ml colloidal sol to move in centrifuge tube, turned with 6500rpm Speed is centrifuged, centrifugation time 10min, carries out washing centrifugation with ultra-pure water again, drop in dry after obtaining concentrated solution after removing mother solution On net silicon chip, it is scanned Electronic Speculum and shoots, obtain Fig. 1.

Embodiment 2：In silver nano-particle solution obtained above, the sodium borohydride adding ultimate density to be 4.5mM is molten Liquid, is stirred vigorously it can be observed that colloidal sol color slightly shows general rufous.1.5ml colloidal sol is taken to move in centrifuge tube afterwards, with 5000rpm rotating speed is centrifuged, centrifugation time 10min, carries out washing centrifugation with ultra-pure water again, obtain concentrated solution after removing mother solution After drop on clean silicon chip, be scanned Electronic Speculum shoot, obtain Fig. 2.Before and after adding sodium borohydride, all use ultra-violet absorption spectrum Characterize the optical property of silver nanoparticle colloidal sol, obtain Fig. 3.

Embodiment 3：Sodium borohydride solution is processed to the surface cleaning of Nano silver grain Raman substrate, and concrete grammar is：

Take 1.5ml step 1) synthesize in resulting solution immigration centrifuge tube, it is centrifuged with 6500rpm rotating speed, centrifugation time 10min, carries out washing centrifugation with ultra-pure water again after removing mother solution, drops on clean silicon chip, obtain unused boron after obtaining concentrated solution The Raman substrate that sodium hydride is processed, gathers spectrum, and LASER Light Source is 532nm, and power is about 12mW, acquisition time 1s.In addition again The Nano silver grain Raman substrate that above-mentioned same procedure is obtained, drips upper 0.1M sodium borohydride solution, after 10s, uses 10mM pyridine Solution rinse three times, after removing remaining sodium borohydride solution, then gathers spectrum, and LASER Light Source is 532nm, and power is about 12mW, Acquisition time 1s.Obtain Fig. 4.

The present invention first prepares 30～100nm Nano silver grain, then using sodium borohydride solution to Nano silver grain surface The silver ion separating out in the oxide existing and in the Nano silver grain hydrosol carries out reduction treatment；Using ultra-violet absorption spectrum And scanning electron microscope characterizes change after sodium borohydride solution before processing, in optical property and pattern for the Nano silver grain；Make With Raman Characterization Nano silver grain substrate, using the spectral signature after sodium borohydride solution before processing.

Claims

1. a kind of method that with sodium borohydride aqueous solution, Nano silver grain is carried out with surface cleaning is it is characterised in that include following walking Suddenly：

1) prepare silver nano-particle solution：In silver perchlorate solution, it is separately added into sodium citrate and ice NaBH₄, with ultrapure Water dilutes, then after mix with silver perchlorate, adds ascorbic acid to react, obtain silver nano-particle solution；Described silver perchlorate solution, Sodium citrate, ice NaBH₄Mol ratio be 1.05: 2.12: 0.96；Nano silver grain in gained silver nano-particle solution Particle diameter is 30～100nm；

2) using sodium borohydride solution, silver nano-particle solution is processed：Sodium borohydride solution is added step 1) gained In silver nano-particle solution, using ultra-violet absorption spectrum technology, the Spectral Extinction of silver nano-particle solution is carried out before treatment afterwards In-situ characterization, result shows, after treatment, Spectral Extinction narrows silver nano-particle solution, and intensity becomes strong, and peak position occurs indigo plant Move, this is because the reason nominal price oxide species of silver surface are reduced；By the silver nano-particle solution after before processing carry out from The heart simultaneously drips sample, then carry out morphology characterization with scanning electron microscope to both it was demonstrated that sodium borohydride solution can effectively be gone back on silicon chip The oxide species on former Nano silver grain surface, and nanoparticle pattern will not be impacted

3) surface cleaning to Nano silver grain Raman substrate for the sodium borohydride solution：By step 2) process after 52nm nano grain of silver Drop on silicon chip after sub- solution centrifugal washing, then drip 10mM pyridine solution, test Raman spectrum；In addition, by step 2) place Drop on silicon chip after silver nano-particle solution centrifuge washing after reason, processed behind surface with 0.1M sodium borohydride solution, then use 10mM pyridine solution rinse, removes sodium borohydride solution, re-test Raman spectrum；Both Raman spectral characteristics of contrast.

2. a kind of method carrying out surface cleaning to Nano silver grain with sodium borohydride aqueous solution as claimed in claim 1, it is special Levy be described ascorbic acid ultimate density be 1.87mM.

3. a kind of method carrying out surface cleaning to Nano silver grain with sodium borohydride aqueous solution as claimed in claim 1, it is special Levy be described reaction time be 2h.

4. a kind of method carrying out surface cleaning to Nano silver grain with sodium borohydride aqueous solution as claimed in claim 1, it is special Levy be described sodium borohydride solution ultimate density be 1～10mM.