| When the molecules adsorbed on metal nano-thin film, the intensity of its infrared absorption bands shows 10-1000 times than the normal measurement conditions, the phenomenon is known as surface-enhanced infrared absorption effect (SEIRA). According to current research, the enhancement of IR. is highly dependent on the morphology of the nanoparticles, size, spacing, the thickness of metal film, as well as the dielectric property of the metal. So the preparation of metal nanoparticles with morphology controlled is essential for SEIRA substrate. Currently, the SEIRA substrates of coins metals (Au, Ag, Cu) were studied more extensively, but little attention to the substrates of the transition metals and alloys were paied. Compare with coins metals, the transition metals and alloy have the same dielectric property and are more cheaper. In this paper, the nanomaterials of Ni and Co-Ni-Cu with surface enhanced infrared effect were prepared by electrochemical deposition, and their spectral characteristics and morphology were characterized by a variety of methods. Then the infrared enhancement mechanism was discussed, and finally the application in biochemistry field with the active substrate were studied. The main contents are as follows:1. Ni nanoparticles were electrochemically deposited on Indium-tin oxide (ITO) coated glass plate. The influence of the infrared enhancement effect were studied with the change of experimental parameters, such as the deposition voltage, deposition time, the pH of solution and the type of surfactants. Also the effect of the surfactant agents on the morphology of nanoparticles were discussed. The results indicate that the morphology of nanoparticles can be well controlled in the deposition potential of 1.3V, time of 30s, pH of 8.92, adding 0.3756mol/Ldiethanolamine as surfactants. The field emission scanning electron microscope (FESEM) observation shows that the morphology of Ni nanoparticles was spherical-like particle, narrowly distributed particles with the average size of 50nm, spacing between the particles was approximately 5nm. According to the infrared spectroscopy, Ni nanoparticles prepared in this condition shows good infrared enhancement effect, and enhancement factor can reach 68. The Co-Ni-Cu substrate was prepared by the same way. The parameters’effect on the composition, morphology and SEIRA of the alloy, such as potential, time, temperature, the concentration of Co2+, pH value, were investigated. The results show that Co-Ni-Cu nanoparticles prepared at potential of-1.0V, time of 60s, temperature of 25℃ and pH of 3.80 have the best enhancement effect. In this case, the proportion of the alloy shows Co:Ni:Cu=2:1:1, the morphology of alloy was spherical-like particle, narrowly distributed particles with the average size of 50nm. The best enhancement factor was about 50.2. According to the spectral characterization of Ni and Co-Ni-Cu substrates, the enhancement effect of substrate changes in different spectral range. Even in the same measurement range, the enhancement effect will be different with the change of measurement methods. Based on the various characterizations and data analysis, the morphology of nanoparticle, such as size, gap, the roughness of the surface can influence the enhancement effect of substrate. Generally, the nanoparticles with good SEIRA effect had the following characteristics:the morphology of nanoparticles was consistent and size of the gap within 10nm, the surface showed a certain roughness.3. ATR-FTIR was used to study the composition of hemodialysis substance, meat tissue and different tissue slice. The results show that ATR-FTIR can be used to analysis and detect biochemical samples, which is fast and easy. The hemodialysis substance and brain tissue on Co-Ni-Cu active substrate were measured. The results show that the active substrates have a certain enhancement effect for hemodialysis substance. When the thickness of the brain tissue was 4μm, active substrate showed enhancement effect for protein. |
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