A surface-enhanced raman substrate and a method of making the same

Abstract

The application belongs to the technical field of in-situ Raman detection, and particularly relates to a surface-enhanced Raman substrate and a preparation method thereof, which comprises the following steps: preparing a perovskite oxide material: the perovskite oxide is obtained by reducing the content of metal at the A position and doping metal at the B position on the basis of an ABO3 type perovskite oxide; and the general formula of the formed perovskite oxide is A x (B' 1‑ y B" y )O 3‑δ , 0

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of in-situ Raman detection, and particularly relates to a surface-enhanced Raman substrate and a preparation method thereof. BACKGROUND

[0002] As an electrochemical energy conversion device, a solid oxide fuel cell (SOFC) has the advantages of high energy conversion rate and less pollutant emission. Electrode materials play an important role in the performance of SOFCs, and the research on the surface of electrode materials can provide guidance for the preparation and optimization of electrode materials with excellent performance. Surface-enhanced Raman spectroscopy (SERS) is a commonly used technology for studying the surface properties of electrodes, and the SERS substrate is a key factor affecting SERS detection.

[0003] The SERS substrates commonly used in the surface reaction of SOFC electrodes, such as Au, Ag, Cu nanoparticles, are mainly prepared by chemical liquid phase reduction method, and then introduced to the surface of electrode materials by methods such as drop coating and deposition, or directly prepared on the surface of electrode by gas phase deposition, so as to further study the Raman spectrum of the surface reaction. This method often has high requirements for the preparation process of metal particles, and the preparation method is complex, and the synthesized nanomaterials will face the problem of agglomeration, which makes it difficult to realize in-situ detection under the high temperature working condition of SOFC. Although the core-shell structure of nanometer metal particles (such as Ag@SiO2, Ag@Al2O3) can avoid the loss of activity due to sintering at high temperature, the synthesis method is more complex and the cost is higher. SUMMARY

[0004] In order to solve the above technical problems, the application provides a surface-enhanced Raman substrate and a preparation method thereof. The SERS substrate is prepared by in-situ nanoparticle out-dissolution technology in perovskite oxide, which can effectively save time and cost. In a solid oxide battery, the electrode material itself can provide an out-dissolved substrate. The anode is in a reducing condition in the working state, which can be used to realize the self-growth of the SERS substrate of the anode under the working condition of the SOFC, and realize the in-situ SERS detection of the anode reaction of the SOFC.

[0005] The application is realized by the following technical solutions.

[0006] The first object of the application is to provide a preparation method of a surface-enhanced Raman substrate, comprising the following steps:

[0007] The perovskite oxide material is prepared, wherein the perovskite oxide is obtained by reducing the content of A-site metal and doping metal at B-site on the basis of ABO3-type perovskite oxide; and the general formula of the formed perovskite oxide is A x (B' 1-yB" y )O 3-δ , 0 < x < 1, 0 < y < 1, A site is an alkaline earth metal, B site metal is composed of B' and B" metal, B' metal is a transition metal, B" metal is a doped metal of B site, and the doped metal is Cu;

[0008] In a reducing gas atmosphere, the doped metal ion of B site is reduced by heating, Cu nanoparticles are in-situ dissolved on the surface of the material to form a surface enhanced Raman substrate.

[0009] In a preferred embodiment of the present application, the perovskite oxide material is fixed in an in-situ Raman chamber, a reducing atmosphere is introduced into the chamber, cooling circulating water is introduced into the bottom of the chamber, the doped metal ion of B site is reduced by heating, and Cu nanoparticles are in-situ dissolved on the surface of the material to form a surface enhanced Raman substrate. In-situ SERS detection can be achieved.

[0010] In a preferred embodiment of the present application, the perovskite oxide material is a solid oxide fuel cell anode.

[0011] In a preferred embodiment of the present application, the perovskite oxide material is Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ , wherein the A site metal is Sr, the B' metal is Ti, and the material is prepared by the following steps:

[0012] SrCO3, TiO2 and CuO are mixed and ball milled, and after drying, a powder precursor is prepared; the powder precursor is calcined at 1250°C for 10h to prepare Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder; the molar ratio of SrCO3, TiO2 and CuO is 9:9:1.

[0013] In a preferred embodiment of the present application, the Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ is placed in an in-situ Raman chamber, and before that, a dissolution sample is prepared, which is prepared by the following steps:

[0014] The Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder is pressed into a disc, and then the disc is sintered at 1300°C for 5h to prepare the dissolution sample.

[0015] In the preferred embodiment of the present application, the leaching sample is fixed in the in-situ Raman chamber, a reducing atmosphere is introduced into the chamber, the bottom of the chamber is connected with cooling circulating water, and the temperature is raised to 400-600℃ to form the leaching copper nanoparticles.

[0016] In the preferred embodiment of the present application, during the process of forming the leaching copper nanoparticles, the temperature is raised to 500℃ and then kept constant, and during the keeping constant time of 40-100min, three points are selected for Raman spectrum testing, and the average of the Raman spectrum intensity of the three points represents the Raman spectrum of the point.

[0017] In the preferred embodiment of the present application, the Raman testing parameters are set as follows: dynamic scanning, exposure time of 10s, scanning range of 160-2000cm -1 Dynamic scanning.

[0018] In the preferred embodiment of the present application, the reducing atmosphere is H2 and N2 mixed gas, and the volume fraction of H2 is 5%.

[0019] In the preferred embodiment of the present application, when the circular tablet is pressed, the pressure is 20Mpa, the diameter of the circular tablet is 1.5cm, and the thickness is 2.5mm.

[0020] In the preferred embodiment of the present application, the ball milling medium is anhydrous ethanol, and the ball milling procedure is as follows: the ball mill is rotated forward for 30min at a speed of 300r / min, and then is reversed for 30min at a speed of 400r / min, and the above process is repeated for 6 times, and the ball milling is performed for 6h in total.

[0021] In the preferred embodiment of the present application, when the powder precursor is calcined, the temperature is raised to 1250℃ at a rate of 5℃ / min and kept constant for 10h, and then the temperature is lowered to room temperature at a rate of 5℃ / min.

[0022] In the preferred embodiment of the present application, when the circular tablet is sintered, the temperature is raised to 1300℃ at a rate of 5℃ / min and kept constant for 5h.

[0023] The second object of the present application is to provide a surface enhanced Raman substrate prepared by the above preparation method.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] In order to solve the problem that the preparation method of the SERS substrate is complex at present, the application provides a method for preparing a SERS substrate by in-situ nanoparticle out-dissolution technology in a perovskite oxide, uses a perovskite oxide (ABO3) as a support frame, reduces the content of the metal at the A position on the basis of the ABO3 type perovskite oxide, and performs metal doping at the B position, the metal ions doped at the B position of the perovskite lattice can be out-dissolved in-situ in the process of reduction. The perovskite structure induces the generation of oxygen defects for maintaining electrical neutrality, and the material formed has a general formula of A x (B’ 1-y B” y )O 3-δ , 0 < x < 1, 0 < y < 1, the metal at the B position is composed of B' and B" metals, the B" metal is a doped metal at the B position, and the defects at the A position (A / B < 1) can provide a better driving force for out-dissolution. The commonly used electrode material itself can provide an out-dissolution substrate, and the anode is in a reduction condition in the working state of the SOFC, so that the SERS substrate can be self-grown in the working condition of the SOFC, and the in-situ SERS detection of the SOFC anode reaction can be realized.

[0026] The method can prepare the oxide substrate supported metal nanoparticles through a relatively simple synthesis path, the synthesized metal nanoparticles are finer, have better distribution, and are high-temperature resistant, so that in-situ detection under the high-temperature working condition of the SOFC can be realized, and time and cost are saved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is an XRD pattern of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder prepared by calcining at 1250 DEG C according to the application.

[0028] Figure 2 It is a grain diagram observed by TEM of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder prepared by calcining at 1250 DEG C according to the application.

[0029] Figure 3 It is a schematic diagram of an in-situ Raman high-temperature reaction cavity according to the application.

[0030] Figure 4 It is an in-situ time-variable Raman spectrum of a Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ sample under a 5% H2 / N2 atmosphere at 500 DEG C.

[0031] Figure 5 Sr for the present invention 0.9 Ti 0.9 Cu 0.1 O 3-δ’ SEM images of the flaky samples after reduction at (a) 300°C, (b) 400°C, (c) 500°C, (d) 600°C for 2h in 5% H2 / N2 atmosphere.

[0032] Figure 6 Sr for the present invention 0.9 Ti 0.9 Cu 0.1 O 3-δ ADF images and EDS-mapping of Cu out-diffusion after reduction of the powder sample at 500°C for 2h; (a) Sr element, (b) Ti element, (c) Cu element, (d) O element.

[0033] Figure 7 High resolution TEM image of Cu out-diffusion particles for the present invention.

[0034] Figure 8 High temperature activity test chart of the substrate prepared by the present invention. DETAILED DESCRIPTION

[0035] In order to make the skilled in the art better understand the technical solutions of the present invention can be implemented, the following specific examples and drawings of the present invention are further described, but the examples are not as a limitation of the present invention.

[0036] The experimental methods and detection methods described in the following examples, such as no special instructions, are conventional methods; the reagents and materials, such as no special instructions, can be purchased on the market.

[0037] Currently, when SERS detection is performed on the surface of the electrode of the SOFC, the substrate used is prepared in a complex manner, for example, the commonly used Au, Ag, Cu and other nanoparticles are mainly prepared by chemical liquid phase reduction method, and then introduced to the surface of the electrode material by drop coating, deposition and other methods, or directly prepared on the surface of the electrode by gas phase deposition and other methods, so as to further perform Raman spectrum research on the surface reaction. This method often has a relatively high requirement for the preparation process of the metal particles, the preparation method is relatively complex, and the synthesized nanometer materials will face the problem of agglomeration, and it is difficult to realize in-situ detection under the high-temperature working condition of the SOFC. The core-shell structure of the nanometer metal particles (such as Ag@SiO2, Ag@Al2O3) can avoid the loss of activity due to sintering at high temperature, but the synthesis method is more complex and the cost is higher. Therefore, the application provides a method for preparing a SERS substrate by in-situ nanoparticle out-dissolution technology in a perovskite oxide, which has a simple preparation method and is resistant to high temperature, and can realize in-situ detection under the high-temperature working condition of the SOFC.

[0038] Specifically, the application provides a preparation method of a surface-enhanced Raman substrate, comprising the following steps:

[0039] Preparation of perovskite oxide material: the perovskite oxide is obtained by reducing the content of A-site metal and doping metal at B-site on the basis of ABO3-type perovskite oxide; and the general formula of the formed perovskite oxide is A x (B’ 1-y B” y )O 3-δ , 0 < x < 1, 0 < y < 1, the A-site is an alkaline earth metal, the B-site metal is composed of B' metal and B" metal, the B' metal is a transition metal, the B" metal is a doped metal at the B-site, and the doped metal is Cu; the perovskite structure is electrically neutral and can induce oxygen defects.

[0040] Fixing the perovskite oxide material in an in-situ Raman chamber, introducing a reducing atmosphere into the chamber, introducing cooling circulating water at the bottom of the chamber, heating to reduce the doped metal ions at the B-site, and out-dissolving nanoparticles in-situ on the surface of the material to form a surface-enhanced Raman substrate, so as to realize in-situ SERS detection.

[0041] The perovskite oxide (ABO3) is used as a support framework, the content of the A-site metal is reduced on the basis of the ABO3-type perovskite oxide, and metal doping is performed at the B-site, the metal ions doped into the B-site of the perovskite lattice can be out-dissolved in-situ under reducing conditions. The defects at the A-site (A / B < 1) can provide a better driving force for out-dissolution.

[0042] In a preferred embodiment of the present application, the perovskite-like oxide material is a solid oxide fuel cell anode. The electrode material itself can provide a dissolution substrate, and the anode is in a reduced state during SOFC operation, which can be used to achieve in-situ SERS detection of SOFC anode reactions by using the anode as a SERS substrate.

[0043] In a preferred embodiment of the present application, the perovskite-like oxide material is Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ , prepared by the following steps:

[0044] SrCO3, TiO2 and CuO are mixed and ball-milled, and after drying, a powder precursor is prepared; the powder precursor is calcined at 1250°C for 10h to prepare a Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder; the molar ratio of SrCO3, TiO2 and CuO is 9:9:1.

[0045] In a preferred embodiment of the present application, the powder precursor is first heated at 5°C / min to 1250°C and held for 10h, and then cooled at 5°C / min to room temperature.

[0046] The Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder is pressed into a disc, and then the disc is heated to 1300°C and sintered for 5h to prepare a dissolution sample.

[0047] In a preferred embodiment of the present application, the pressure during pressing into a disc is 20Mpa, the disc diameter is 1.5cm, and the thickness is 2.5mm. During sintering of the disc, the temperature is increased at 5°C / min to 1300°C and sintered for 5h.

[0048] The dissolution sample is fixed in a Raman chamber, a reducing atmosphere is introduced into the chamber, cooling circulating water is introduced into the bottom of the chamber, and the temperature is increased to 400-600°C to form dissolution copper nanoparticles.

[0049] In a preferred embodiment of the present application, during formation of the dissolution copper nanoparticles, the temperature is increased to 500°C and held, and during the holding time of 60-100min, Raman spectra are tested at three points, and the average of the Raman spectrum intensities of the three points is used to represent the Raman spectrum at the point. The Raman test parameters are set as follows: dynamic scanning is set, the exposure time is 10s, the scanning range is 160-2000cm -1Dynamic scanning. In-situ SERS detection is realized.

[0050] In a preferred embodiment of the present application, the reducing atmosphere is a mixture of H2 and N2, and the volume fraction of H2 is 5%.

[0051] In a preferred embodiment of the present application, the ball milling medium is anhydrous ethanol, and the ball milling procedure is as follows: forward rotation of the ball mill for 30 min at a speed of 300 r / min, reverse rotation for 30 min at a speed of 400 r / min, and the above process is repeated for 6 times, and the ball milling is performed for 6 h in total.

[0052] The commonly used electrode material itself can provide a dissolved substrate, and the anode is in a reducing condition in the working state of the SOFC, so that the SERS substrate can be self-grown under the working condition of the SOFC, and in-situ SERS detection of the anode reaction of the SOFC is realized.

[0053] The content of the present application is described below in detail through the following examples and comparative examples, taking a perovskite oxide material as Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ as an example, in which in-situ dissolution of nanoparticles forms a Raman enhancement substrate.

[0054] Example 1

[0055] A kind of nano copper particle Raman enhancement substrate based on in-situ nanoparticle dissolution technology, and the specific steps are as follows:

[0056] 6.64326 g of SrCO3, 3.59393 g of TiO2 and 0.39773 g of CuO powder were weighed by an analytical balance and placed in a ball mill tank, and then grinding balls and an appropriate amount of anhydrous ethanol were added, and the ball mill was forward rotated for 30 min at a speed of 300 r / min, and then reverse rotated for 30 min at a speed of 400 r / min, and the above process was repeated for 6 times, and the ball milling was performed for 6 h in total. The paste-like precursor after ball milling was placed in a vacuum drying box together with the ball mill tank, and dried at 80℃ for 5 h to obtain a dry powder precursor. The precursor powder was placed in a high-temperature box furnace, and the high-temperature box furnace was set to increase the temperature to 1250℃ at a rate of 5℃ / min and maintain the temperature for 10 h, and then decrease the temperature to room temperature at a rate of 5℃ / min, to obtain a calcined Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder.

[0057] Figure 1 , Figure 2 The above are calcined Sr 0.9 Ti 0.9 Cu 0.1 O 3-δXRD pattern and TEM observation of the powder grains, it can be seen that Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ was successfully synthesized.

[0058] Take about 0.5g of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder, and press it into a circular sheet sample with a diameter of 1.5 cm using a manual press, and sinter it in a box furnace at a temperature of 1300℃ at a rate of 5℃ / min for 5h.

[0059] Put the obtained circular sheet sample into a tube furnace, and pass a 5% H2 / N2 atmosphere at a flow rate of 20ml / min through the furnace, and set the tube furnace to a temperature of 400℃ at a rate of 5℃ / min, and maintain the temperature for 2h, and then cool it down to obtain a sample after separate reduction atmosphere dissolution treatment, and then further characterize the dissolved Cu.

[0060] Example 2

[0061] A kind of in-situ nanoparticle dissolution technology based on nano copper particle Raman enhancement substrate, the tube furnace is heated to 500℃, and the specific steps are as follows:

[0062] Take 6.64326g of SrCO3, 3.59393g of TiO2 and 0.39773g of CuO powder, and put them into a ball mill jar, add grinding balls and an appropriate amount of anhydrous ethanol, and run the ball mill at a speed of 300r / min for 30min, and then reverse it at a speed of 400r / min for 30min, repeat the above process 6 times, and ball mill for a total of 6h. Put the ball-milled paste precursor into a vacuum drying oven together with the ball mill jar, and dry it at 80℃ for 5h to obtain dry powder precursor. Take the precursor powder and put it into a high-temperature box furnace, and set the high-temperature box furnace to a temperature of 1250℃ at a rate of 5℃ / min and maintain the temperature for 10h, and then cool it down to room temperature at a rate of 5℃ / min to obtain calcined Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder.

[0063] Take about 0.5g of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder, and press it into a circular sheet sample with a diameter of 1.5 cm using a manual press, and sinter it in a box furnace at a temperature of 1300℃ at a rate of 5℃ / min for 5h.

[0064] The obtained wafer sample was placed in a tube furnace, a 5% H2 / N2 atmosphere of 20 ml / min was passed in the furnace, the tube furnace was set to 5 ℃ / min to 500 ℃, and after 2 h of heat preservation, the temperature was lowered to obtain the sample after the out-dissolution treatment in the single reduction atmosphere, and then the out-dissolved Cu was further characterized.

[0065] Example 3

[0066] A kind of nano copper particle Raman enhancement substrate based on in-situ nanoparticle out-dissolution technology, the tube furnace is heated to 600 ℃, and the specific steps are as follows:

[0067] 6.64326 g of SrCO3, 3.59393 g of TiO2 and 0.39773 g of CuO powder were weighed with an analytical balance and placed in a ball mill jar, and a proper amount of anhydrous ethanol was added. The ball mill was rotated at 300 r / min for 30 min and reversed at 400 r / min for 30 min. The above process was repeated 6 times, and the ball milling was performed for 6 h. The ball-milled paste precursor was placed in a vacuum drying oven together with the ball mill jar, and dried at 80 ℃ for 5 h to obtain a dry powder precursor. The precursor powder was placed in a high-temperature box furnace, and the high-temperature box furnace was set to 5 ℃ / min to 1250 ℃ for 10 h, and then cooled to room temperature at 5 ℃ / min to obtain the calcined Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder.

[0068] About 0.5 g of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder was pressed into a wafer sample with a diameter of 1.5 cm by a manual press, and sintered at 5 ℃ / min to 1300 ℃ for 5 h in a box furnace.

[0069] The obtained wafer sample was placed in a tube furnace, a 5% H2 / N2 atmosphere of 20 ml / min was passed in the furnace, the tube furnace was set to 5 ℃ / min to 600 ℃, and after 2 h of heat preservation, the temperature was lowered to obtain the sample after the out-dissolution treatment in the single reduction atmosphere, and then the out-dissolved Cu was further characterized.

[0070] Comparative Example 1

[0071] A kind of nano copper particle Raman enhancement substrate based on in-situ nanoparticle out-dissolution technology, the tube furnace is heated to 300 ℃, and the specific steps are as follows:

[0072] Weigh 6.64326 g of SrCO3, 3.59393 g of TiO2, and 0.39773 g of CuO powder using an analytical balance and place them in a ball mill jar. Add grinding balls and an appropriate amount of anhydrous ethanol. The ball mill is rotated clockwise for 30 min at 300 rpm, then counterclockwise for 30 min at 400 rpm. This process is repeated 6 times for a total of 6 hours. The ball-milled paste-like precursor, along with the ball mill jar, is placed in a vacuum drying oven and dried at 80°C for 5 hours to obtain a dried powder precursor. The precursor powder is then placed in a high-temperature box furnace. The furnace is heated to 1250°C at a rate of 5°C / min and held for 10 hours, followed by cooling to room temperature at a rate of 5°C / min to obtain calcined SrCO3. 0.9 Ti 0.9 Cu 0.1 O 3-δ powder.

[0073] Take approximately 0.5g of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ The powder was pressed into circular samples with a diameter of 1.5 cm using a manual press, and sintered in a box furnace at a temperature of 5℃ / min to 1300℃ for 5 hours.

[0074] The obtained disc samples were placed in a tube furnace, and a 5% H2 / N2 atmosphere of 20 ml / min was introduced into the furnace. The tube furnace was set to heat up to 300℃ at 5℃ / min, and after holding at this temperature for 2 hours, it was cooled down to obtain the sample after being treated with a reducing atmosphere. Then, further experiments were conducted to characterize the Cu that had been expelled.

[0075] like Figure 5 It is evident that the sample surfaces reduced at 500℃ and 600℃ for 2 hours exhibit dense nanoparticles, and the particle size of Cu particles on the sample surface increases with increasing temperature. The sample surface after reduction at 400℃ is covered with a layer of fine, gravelly particles, with even denser particle density observed in relatively wrinkled areas of the sample surface. Therefore, Cu exsolution also occurred on the surface of the sheet-like sample at 400℃, while almost no Cu particles are visible on the surface of the sample treated at 300℃. At the reduction temperature, the obtained Cu nanoparticles all have a particle size less than 100 nm, which meets the particle size requirements of the SERS effect.

[0076] Figure 6 Sr was studied using a Talos F200X Lorentz transmission electron microscope manufactured by Thermo Fisher Scientific, USA. 0.9 Ti 0.9 Cu 0.1 O 3-δ Further research was conducted on Cu particles exsolved on the perovskite matrix, and Sr... 0.9 Ti 0.9 Cu0.1 O 3-δ The powder sample was reduced at 500℃ for 2h to get Cu out-diffused (a) ADF image and EDS-mapping; (b) Sr element, (c) Ti element, (d) Cu element, (e) O element. From the EDS-mapping images, it can be clearly seen that the Sr, Ti, O elements only exist in the "platform" in the lower half, and the hemispherical particles floating out of the perovskite matrix have and only have Cu element, so it can further prove that the nanoparticles observed in the SEM image are Cu nanoparticles. Figure 7 A side view of the out-diffused particles captured during the study of the out-diffused sample using TEM.

[0077] Example 4

[0078] A Raman enhancement substrate based on in-situ nanoparticle out-diffusion technology, the specific steps are as follows:

[0079] Take 6.64326g of SrCO3, 3.59393g of TiO2, and 0.39773g of CuO powder with an analytical balance and put them into a ball mill jar. Add grinding balls and an appropriate amount of anhydrous ethanol. Run the ball mill at 300r / min for 30min, and then at 400r / min for 30min. Repeat the above process 6 times, for a total of 6h of ball milling. Place the ball-milled paste and the ball mill jar in a vacuum drying oven and dry at 80℃ for 5h to obtain a dry powder precursor. Take the precursor powder and place it in a high-temperature box furnace. Set the high-temperature box furnace to heat at 5℃ / min to 1250℃ and hold for 10h. Then cool it down to room temperature at 5℃ / min. Obtain the calcined Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder.

[0080] To prepare a sample suitable for the Raman cavity, take 1.6g of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder and use a manual press to press it at a pressure of about 20Mpa to obtain a circular sheet sample with a diameter of 1.5cm and a thickness of about 2.5mm. Then place it in a box furnace and heat it at 5℃ / min to 1300℃ and sinter for 5h.

[0081] Figure 3The schematic diagram of the in-situ Raman high-temperature reaction chamber is shown. During in-situ testing, the obtained wafer is fixed on the sample stage of the in-situ Raman chamber using a high-temperature resistant adhesive. A 5% H2 / N2 atmosphere is continuously introduced into the chamber at a flow rate of about 15 ml / min. Cooling circulating water is introduced into the chamber bottom. The EZ-zone software of the ATK-024-4 temperature control device is used to set the temperature program. The temperature is increased to 500°C at a rate of 10°C / min. The temperature is maintained at 500°C for 40 min.

[0082] Example 5

[0083] A kind of in-situ nanoparticle out of solution technology based on nano copper particle Raman enhancement substrate, in in-situ Raman high-temperature reaction chamber, 500 ℃ is maintained for 60 min, its specific steps are as follows:

[0084] 6.64326 g of SrCO3, 3.59393 g of TiO2 and 0.39773 g of CuO powder are weighed using an analytical balance and placed in a ball mill jar. Appropriate amount of anhydrous ethanol is added, and the ball mill is rotated at 300 r / min for 30 min and then reversed at 400 r / min for 30 min. The above process is repeated 6 times, and the ball milling is performed for a total of 6 h. The ball-milled paste precursor is placed in a vacuum drying oven together with the ball mill jar, and dried at 80°C for 5 h to obtain a dry powder precursor. The precursor powder is placed in a high-temperature box furnace, and the high-temperature box furnace is set to increase the temperature to 1250°C at a rate of 5°C / min and maintain the temperature for 10 h. Then, the temperature is decreased to room temperature at a rate of 5°C / min. The calcined Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder is obtained.

[0085] To prepare a sample suitable for the Raman chamber, 1.6 g of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder is used. A manual press is used to press the powder under a pressure of about 20 MPa to obtain a wafer-shaped sample with a diameter of 1.5 cm and a thickness of about 2.5 mm. The wafer is then placed in a box furnace and sintered at a rate of 5°C / min to 1300°C for 5 h.

[0086] Figure 3 The schematic diagram of the in-situ Raman high-temperature reaction chamber is shown. During in-situ testing, the obtained wafer is fixed on the sample stage of the in-situ Raman chamber using a high-temperature resistant adhesive. A 5% H2 / N2 atmosphere is continuously introduced into the chamber at a flow rate of about 15 ml / min. Cooling circulating water is introduced into the chamber bottom. The EZ-zone software of the ATK-024-4 temperature control device is used to set the temperature program. The temperature is increased to 500°C at a rate of 10°C / min. The temperature is maintained at 500°C for 60 min.

[0087] Example 6

[0088] A kind of in-situ nanoparticle out of solution technology based on nano copper particle Raman enhancement substrate, in-situ Raman high temperature reaction cavity, 500 ℃, 100 min, its specific steps are as follows:

[0089] 6.64326 g SrCO 3, 3.59393 g TiO 2, 0.39773 g CuO powder is weighed with analytical balance and placed in a ball mill jar, add grinding balls and appropriate amount of anhydrous ethanol, the ball mill is forward rotated for 30 min, the speed is 300 r / min, reverse rotation for 30 min, the speed is 400 r / min, the above process is repeated 6 times, a total of 6h ball milling. The ball-milled paste precursor is placed in a vacuum drying oven together with the ball mill jar, and dried at 80 ℃ for 5h to obtain dry powder precursor. The precursor powder is placed in a high temperature box furnace, and the high temperature box furnace is set to 5 ℃ / min to 1250 ℃, 10h, and then 5 ℃ / min to room temperature, to obtain the calcined Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ Powder.

[0090] To prepare a sample suitable for the Raman cavity, 1.6 g of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ Powder, using a manual press, under a pressure of about 20Mpa, respectively pressed to obtain a circular sheet sample with a diameter of 1.5 cm and a thickness of about 2.5 mm, and then placed in a box furnace and sintered at 5 ℃ / min to 1300 ℃ for 5h.

[0091] Figure 3 As shown, the schematic diagram of the in-situ Raman high temperature reaction cavity, in-situ test, the obtained circular sheet is fixed on the sample stage of the in-situ Raman cavity using high temperature resistant adhesive, a 5% H 2 / N 2 atmosphere is continuously introduced into the chamber at a flow rate of about 15 ml / min, the bottom of the chamber is connected to cooling circulating water, and the EZ-zone software of the ATK-024-4 temperature control device is used to set the program to heat at 10 ℃ / min to 500 ℃, and heat at this temperature for 100 min.

[0092] Comparative Example 2

[0093] A kind of in-situ nanoparticle out of solution technology based on nano copper particle Raman enhancement substrate, in-situ Raman high temperature reaction cavity, 500 ℃, 120 min, its specific steps are as follows:

[0094] Take 6.64326 g of SrCO3, 3.59393 g of TiO2, 0.39773 g of CuO powder on an analytical balance, put them into a ball mill jar, add grinding balls and an appropriate amount of anhydrous ethanol, run the ball mill at 300 r / min for 30 min, reverse at 400 r / min for 30 min, repeat the above process 6 times, a total of 6 h of ball milling. Put the ball-milled paste precursor together with the ball mill jar in a vacuum drying oven, dry at 80℃ for 5 h to obtain a dry powder precursor. Take the precursor powder and put it into a high-temperature box furnace, set the high-temperature box furnace to 1250℃ at a rate of 5℃ / min and keep it for 10 h, then cool it to room temperature at a rate of 5℃ / min, to obtain the calcined Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder.

[0095] To prepare a sample suitable for the Raman cavity, take 1.6 g of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder, use a manual press to press it at a pressure of about 20 MPa to obtain a circular sheet sample with a diameter of 1.5 cm and a thickness of about 2.5 mm, and then place it in a box furnace and sinter it at a rate of 5℃ / min to 1300℃ for 5 h.

[0096] Figure 3 The in-situ Raman high-temperature reaction cavity is shown in the schematic diagram, during in-situ testing, the obtained circular sheet is fixed on the sample stage of the in-situ Raman cavity using a high-temperature resistant adhesive, a 5% H2 / N2 atmosphere is continuously introduced into the chamber at a flow rate of about 15 ml / min, cooling circulating water is introduced into the chamber bottom, and the EZ-zone software of the ATK-024-4 temperature control device is used to set the temperature program to increase the temperature to 500℃ at a rate of 10℃ / min, and keep it at this temperature for 120 min.

[0097] Comparative Example 3

[0098] A kind of nano copper particle Raman enhancement substrate based on in-situ nanoparticle out-solution technology, in an in-situ Raman high-temperature reaction cavity, 500℃ keeps 0 min, its specific steps are as follows:

[0099] Take 6.64326 g of SrCO3, 3.59393 g of TiO2, 0.39773 g of CuO powder on an analytical balance, put them into a ball mill jar, add grinding balls and an appropriate amount of anhydrous ethanol, run the ball mill for 30 min at 300 r / min, reverse for 30 min at 400 r / min, repeat the above process 6 times, a total of 6 h of ball milling. Put the ball-milled paste into a vacuum drying oven together with the ball mill jar, dry at 80 ℃ for 5 h to obtain a dry powder precursor. Take the precursor powder and put it into a high-temperature box furnace, set the high-temperature box furnace to 1250 ℃ at a rate of 5 ℃ / min and keep it for 10 h, then cool it to room temperature at a rate of 5 ℃ / min, to obtain the calcined Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder.

[0100] To prepare a sample suitable for the Raman cavity, take 1.6 g of Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder, use a manual press to press it at a pressure of about 20 MPa to obtain a circular sheet sample with a diameter of 1.5 cm and a thickness of about 2.5 mm, and then place it in a box furnace and sinter it at a rate of 5 ℃ / min to 1300 ℃ for 5 h.

[0101] Figure 3 As shown in the figure, the schematic diagram of the in-situ Raman high-temperature reaction cavity, when in-situ tested, the obtained circular sheet is fixed on the sample stage of the in-situ Raman cavity using a high-temperature resistant adhesive, a 5% H2 / N2 atmosphere is continuously introduced into the chamber at a flow rate of about 15 ml / min, cooling circulating water is introduced into the chamber bottom, and the EZ-zone software of the ATK-024-4 temperature control device is used to set the temperature rising program to 500 ℃ at a rate of 10 ℃ / min, and keep it at this temperature for 0 min.

[0102] Randomly select 3 points on the surface of the samples in Examples 4-7 and Comparative Example 2 for Raman spectrum testing, and take the average of the Raman spectrum intensities of the three points as the Raman spectrum at the corresponding holding time. Figure 4 The in-situ time-variable Raman spectrum of the Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ sample during the 500 ℃ holding process under a 5% H2 / N2 atmosphere. As can be seen very intuitively in the figure, during the entire 2 h reduction process at 500 ℃, the Sr 0.9 Ti 0.9 Cu 0.1 O 3-δThe intensity of Raman spectrum changed greatly in 2h, the peak intensity increased gradually in 0-60min, and decreased in 80min, and decreased greatly in 120min. The enhancement process is attributed to the early stage of reduction reaction, with the time going, more Cu element is out of solution as nanoparticles, the size of Cu nanoparticles on the surface of sample increases and the density increases, and the SERS enhancement is more significant. The weakening process can be attributed to the aggregation of small Cu particles in the late stage of out of solution, that is, the density of Cu particles decreases, the size increases, and then the SERS active sites decrease, and the SERS effect weakens.

[0103] The experiment verifies that the substrate prepared by the application has good high-temperature activity:

[0104] 1.6g of Sr 0.9 Ti 0.9 Cu 0.1 O3 powder is pressed into a circular sheet sample with a diameter of 1.5cm and a thickness of about 2.5mm under a pressure of about 20Mpa using a manual press, and then placed in a box furnace and sintered at 1300℃ for 5h at a temperature increasing rate of 5℃ / min. During in-situ testing, the circular sheet is fixed on the sample stage in the Raman cavity using a high-temperature resistant adhesive, a 5% H2 / N2 atmosphere is continuously introduced into the cavity at a flow rate of about 15ml / min, and cooling circulating water is introduced into the bottom of the cavity. For the temperature control system, the EZ-zone software matched with the ATK-024-4 temperature control device is used to set the temperature increasing program so that the Raman cavity is heated at a rate of 10℃ / min to 600℃, and every 100℃, the temperature increasing is paused for 7.5min, and during the 7.5min of temperature maintenance, a group of Raman spectra is measured at three points on the surface of the sample, and the average of the three groups of data is taken as the Raman spectrum at the temperature. After the last measurement at 600℃ is completed, the program is terminated and the water cooling is started. The Raman test parameters are set as follows: dynamic scanning, exposure time 10s, scanning range 160-2000cm -1 .

[0105] The in-situ Raman spectrum of the temperature increasing process is shown in Figure 8 According to Figure 8 we can see macroscopically that the Cu-doped sample shows a spectrum peak with temperature increasing, generally speaking, temperature increasing will cause higher molecular / atomic kinetic energy, and for a crystal, it will cause stronger lattice vibration, and the Raman spectrum of the crystal reflects the strength of the lattice vibration, so the similar spectrum peak with temperature increasing can be observed in the sample, on the other hand, it is attributed to the generation of oxygen vacancies in the reduction process, which destroys the symmetry of the perovskite crystal to a greater extent, that is, the polarity of the perovskite crystal is enhanced, thereby showing stronger Raman activity. In addition, obvious Raman enhancement effect can be seen at 500℃ and 600℃, which verifies that the substrate prepared by the application has the advantage of good high-temperature activity.

[0106] It can be seen from the above characterization results that the method for preparing the SERS substrate by in-situ nanoparticle out-diffusion technology in the perovskite oxide is feasible, the synthesized metal nanoparticles are more fine and better distributed, and are resistant to high temperature, the SOFC anode material itself can provide the out-diffusion substrate, the anode is in a reduction condition in the working state, and thus the self-growth of the SERS substrate by the anode under the SOFC working condition can be realized, in-situ detection under the SOFC high-temperature working condition can be realized, and the operation is simple, so the method is suitable for popularization and use.

[0107] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and the equivalent technologies thereof, these modifications and variations are also intended to be included.

Claims

1. A method of preparing a surface enhanced Raman substrate, characterized by, The method comprises the following steps: Preparation of a perovskite-like oxide material: the perovskite-like oxide material is Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ , by the following steps: SrCO3, TiO2and CuO were mixed and ball-milled, and after drying, a powder precursor was prepared; after the powder precursor was calcined at 1250°C for 10h, Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ powder was prepared; the molar ratio of SrCO3, TiO2and CuO was 9:9:1; Sr 0.9 Ti 0.9 Cu 0.1 O 3-δ The powder was pressed into a disc, which was then sintered at 1300°C for 5 h to produce a solution sample. The leaching sample is fixed in a Raman chamber, a reducing gas is introduced into the chamber, cooling circulating water is introduced into the bottom of the chamber, the temperature is raised to 400-600 DEG C, leaching copper nanoparticles are formed, and a surface enhanced Raman substrate is formed.

2. The production method according to claim 1, characterized by, When being pressed into a round sheet, the pressure is 20 Mpa, the diameter of the round sheet is 1.5 cm, and the thickness is 2.5 mm.

3. The preparation method according to claim 1, characterized in that, In the process of forming the leaching copper nanoparticles, the temperature is raised to 500 DEG C and then kept, Raman spectrum tests are performed on three points in the process of keeping for 40-100 min, and the average of the Raman spectrum intensities of the three points represents the Raman spectrum under the corresponding keeping time.

4. The preparation method according to claim 3, characterized in that, Raman spectroscopy test parameter settings: Set dynamic scan, exposure time 10 s, scan range 160-2000 cm -1 Dynamic scan.

5. The preparation method according to claim 1, characterized in that, The reducing gas is H2 and N2 mixed gas, and the volume fraction of H2 is 5%.

6. The method of claim 1, wherein, The perovskite oxide material is a solid oxide fuel cell anode.

7. The surface enhanced Raman substrate prepared by the preparation method according to any one of claims 1-6.

Images