Carbon-based catalyst as well as preparation method and application thereof
By modifying the carbon-based material of ginkgo leaves, combining metal hydroxides and nitrogen-containing compounds, a carbon-based catalyst with high catalytic activity and stability is prepared, which solves the problems of high cost and poor stability of existing precious metal catalysts, and achieves environmentally friendly and economical catalyst effects.
Patent Information
- Application Number
- CN202410075577.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-18
- Publication Date
- 2025-03-11
AI Technical Summary
Existing fuel cell catalysts mainly rely on precious metals such as platinum, which are cost-effective and have poor stability, making it difficult to meet environmentally friendly and affordable catalyst needs.
By using ginkgo leaves as raw materials, combined with metal hydroxides and nitrogen-containing compounds for modification, a carbon-based catalyst with good stability and high catalytic activity was prepared.
A carbon-based catalyst with excellent catalytic activity and good stability at high current density is achieved, reducing the cost of fuel cell catalysts and meeting environmentally friendly requirements.
Smart Images
Figure CN119601682A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of redox catalysts, and in particular to a carbon-based catalyst and a preparation method and application thereof. Background Art
[0002] Fossil energy (including coal, oil and natural gas) has long been the main source of energy. However, the overuse of fossil fuels has led to an energy crisis and many environmental and climate problems, such as greenhouse gas emissions and global warming. In order to cope with these problems and achieve sustainable development of energy, people began to look for new energy technologies.
[0003] Fuel cells are considered a sustainable energy technology with great potential. Their main advantages include high energy conversion, zero emissions, low noise and flexibility. They can be widely used in transportation, power supply, construction and mobile equipment. Moreover, fuel cells can produce hydrogen using various renewable energy sources, such as solar energy, wind energy and biomass energy.
[0004] Redox reaction is the core step of fuel cell energy conversion. However, the mainstream catalysts on the market are mainly precious metal catalysts based on platinum carbon, which are expensive and have poor stability. Therefore, it is urgent to find a catalyst that is environmentally friendly, low-cost, and has good stability and catalytic activity. Summary of the invention
[0005] In order to solve the problems existing in the prior art, the present invention provides a carbon-based catalyst and a preparation method and application thereof.
[0006] Ginkgo biloba is a renewable resource and is more environmentally friendly than traditional catalysts. It is inexpensive to prepare carbon-based catalyst materials using it as a raw material. After proper treatment, it has a rich porous structure and a large specific surface area, which can provide more catalytic sites and thus show good catalytic activity. However, compared with metal phase catalysts, the conductivity of ginkgo biloba carbon-based materials is poor, which may limit its catalytic activity in high current density reactions. In addition, problems such as decarbonization or structural changes may occur during long-term use, affecting its long-term stability.
[0007] In order to solve the corresponding technical problems, the present invention modifies the ginkgo leaf carbon-based material by adding metal hydroxides and nitrogen-containing compounds to prepare a ginkgo leaf carbon-based catalyst with good stability and excellent catalytic activity at high current density.
[0008] In a first aspect, the present invention provides a carbon-based catalyst prepared from raw materials including the following components: ginkgo leaves, metal hydroxides and nitrogen-containing compounds;
[0009] In parts by weight, the ginkgo leaf is 1 to 10 parts, the metal hydroxide is 1 to 10 parts, and the nitrogen-containing compound is 0.05 to 2 parts.
[0010] Furthermore, the ginkgo leaf is 1 to 3 parts, the metal hydroxide is 1 to 3 parts, and the nitrogen-containing compound is 0.07 to 0.6 parts.
[0011] Furthermore, the mass ratio of the ginkgo leaf to the nitrogen-containing compound is 1:(0.035-0.262).
[0012] Furthermore, the raw materials also include acid and water.
[0013] Furthermore, the metal hydroxide includes: one or more of potassium hydroxide or sodium hydroxide.
[0014] Furthermore, the nitrogen-containing compound includes: one or more of thiourea, melamine or urea.
[0015] In a second aspect, the present invention provides a method for preparing a carbon-based catalyst, comprising:
[0016] Based on Ginkgo biloba leaves, carbonization, pH neutralization and nitrogen hybridization were carried out;
[0017] Metal hydroxide is added during the carbonization process.
[0018] Further, the carbonization treatment includes: heating the ginkgo leaves to 200°C to 500°C under a temperature increase condition of 3°C / min to 10°C / min for 1 to 4 hours to obtain a pre-carbonized sample;
[0019] The pre-carbonized sample and the metal hydroxide are mixed, and the mixture is heated to 700° C. to 900° C. at a temperature of 3° C. / min to 10° C. / min for 0.5 h to 3 h, and then cooled to 20 to 30° C. to obtain a mixed carbon sample.
[0020] The present invention adopts a continuously increasing temperature method in the two-step carbonization process of ginkgo leaves, and the obtained carbonized ginkgo leaves have better specific surface area and catalytic performance.
[0021] Further, the pH neutralization comprises:
[0022] The mixed carbon sample prepared by the carbonization treatment is placed in water to obtain a suspension; the pH value of the suspension is adjusted to acidic with an acid and stirred for 6 to 12 hours to obtain an acidic suspension; the acidic suspension is washed to neutral with water, then filtered and dried to obtain an activated carbon sample.
[0023] Furthermore, the pH value is preferably adjusted to 1 to 1.5.
[0024] Furthermore, the acid used may be an acidic solution commonly used in the art, such as a concentrated nitric acid solution, and the amount used may be 1 / (50-1000) of the volume of the suspension.
[0025] Furthermore, the rotation speed of the stirring process is 200 to 700 r / min.
[0026] The present invention uses acid to treat the carbonized ginkgo leaves and then performs a neutralization treatment to make them neutral, thereby effectively improving the catalytic performance of the carbonized ginkgo leaves.
[0027] Furthermore, the nitrogen hybridization treatment includes:
[0028] After the pH-neutralized activated carbon sample and the nitrogen-containing compound are mixed, the temperature is increased to 700°C to 1000°C at a temperature increase of 3°C / min to 10°C / min for 1 to 5 hours, and then cooled to 20 to 30°C.
[0029] Furthermore, the mass ratio of the activated carbon sample to the nitrogen-containing compound is 1:(0.5-5).
[0030] Furthermore, the mass ratio of the activated carbon sample to the nitrogen-containing compound is 1:(1-4).
[0031] In a third aspect, the present invention provides a carbon-based catalyst prepared by the preparation method.
[0032] In a fourth aspect, the present invention provides the carbon-based catalyst, or the use of the carbon-based catalyst in fuel cells and metal-air batteries.
[0033] The present invention has the following beneficial effects:
[0034] The present invention provides a carbon-based catalyst and a corresponding preparation method based on carbonized ginkgo leaves. In the process of carbonizing the ginkgo leaves, the present invention uses metal hydroxides for modification, and then uses nitrogen-containing compounds for nitrogen hybridization to obtain a ginkgo leaf carbon-based material with good stability and excellent catalytic activity at high current density, which can meet the catalyst performance requirements of current fuel cells.
[0035] The carbon-based catalyst provided by the present invention is environmentally friendly and low in cost. It can meet the requirements of sustainable development while ensuring economic benefits, and provides a new idea for the research and development of alternatives to the currently expensive commercial platinum-carbon. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0037] Figure 1 It is a linear voltammetric scan diagram of the ginkgo leaf carbon-based catalyst prepared in different embodiments and comparative examples provided by the present invention.
[0038] Figure 2 Cyclic voltammetry curves of ginkgo leaf carbon-based catalysts prepared in different embodiments and comparative examples provided by the present invention.
[0039] Figure 3 It is a comparison chart of hydrogen peroxide generation rate and electron transfer number of the ginkgo leaf carbon-based catalyst and platinum carbon prepared in Example 2 and Comparative Example 1 provided by the present invention.
[0040] Figure 4 It is a Tafel plot comparing the carbon-based catalyst prepared in Example 2 provided by the present invention with platinum-carbon.
[0041] Figure 5 These are the CV graphs and linear voltammetric scanning graphs of Example 2 and platinum-carbon provided by the present invention at the beginning and after 2000 cycles.
[0042] Figure 6 The embodiment 2 provided by the present invention and the platinum carbon are respectively at 100mA / cm 2 and 50mA / cm 2 Discharge time test chart under conditions.
[0043] Figure 7 1 and 3 are XRD diagrams of Comparative Example 1 and Comparative Example 3 provided by the present invention; wherein the acidified one is Comparative Example 1, and the unacidified one is Comparative Example 3. DETAILED DESCRIPTION
[0044] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0045] Example 1
[0046] This embodiment provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0047] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0048] 2. Take 1g of the pre-carbonized sample and 2g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 5℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 1h, then cool naturally to room temperature to obtain a mixed carbon sample for standby use.
[0049] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 8h to obtain an acidic solution of a certain concentration.
[0050] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain 0.14g of activated carbon sample.
[0051] 5. Weigh 0.05g of activated carbon and 0.05g of thiourea in a mortar, grind them thoroughly and mix them into a porcelain boat. Put it into a tubular furnace and set the heating rate to 5℃ / min under a nitrogen atmosphere. Raise the temperature in the furnace to 850℃ and calcine for 3h. Cool it naturally to room temperature to obtain the ginkgo leaf carbon-based catalyst.
[0052] The prepared Ginkgo biloba carbon-based catalyst was subjected to linear voltammetry and cyclic voltammetry tests using a rotating disk electrode apparatus. The half-wave potential and starting potential were used to reflect the catalytic activity of the catalyst. The results are shown in Figure 1 and Figure 2 As shown, the half-wave potential and starting potential of the carbon-based catalyst prepared in this example are 0.8033V and 0.8756V.
[0053] Example 2
[0054] This embodiment provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0055] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0056] 2. Take 1g of the pre-carbonized sample and 2g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 5℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 1h, then cool naturally to room temperature to obtain a mixed carbon sample for standby use.
[0057] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 8h to obtain an acidic solution of a certain concentration.
[0058] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain 0.14g of activated carbon sample.
[0059] 5. Weigh 0.05g activated carbon and 0.1g thiourea in a mortar, grind them thoroughly and mix them into a porcelain boat. Put it into a tubular furnace and set the heating rate to 5℃ / min under a nitrogen atmosphere. Raise the temperature in the furnace to 850℃ and calcine for 3h. Cool it naturally to room temperature to obtain the ginkgo leaf carbon-based catalyst.
[0060] The prepared ginkgo leaf carbon-based catalyst was subjected to linear voltammetry and cyclic voltammetry tests using a rotating disk electrode device. Its half-wave potential and starting potential reflected the catalytic activity of the catalyst, and the catalyst stability test was also performed. A high-performance battery detection system was used to perform an aluminum-air battery discharge test. The results are as follows: Figure 1-Figure 6 As shown in the figure, the half-wave potential of the carbon-based catalyst prepared in this example is 0.8756V, the starting potential is 0.9135V, and it still has good catalytic activity after two thousand scans. The electron transfer number-hydrogen peroxide conversion rate graph and Tafel curve graph are made. At 50mA / cm 2 and 100mA / cm 2 The battery can be discharged stably for 45h and 49h at a high current density.
[0061] Example 3
[0062] This embodiment provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0063] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0064] 2. Take 1g of the pre-carbonized sample and 2g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 5℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 1h, then cool naturally to room temperature to obtain a mixed carbon sample for standby use.
[0065] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 8h to obtain an acidic solution of a certain concentration.
[0066] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain 0.14g of activated carbon sample.
[0067] 5. Weigh 0.05g activated carbon and 0.15g thiourea in a mortar, grind them thoroughly and mix them into a porcelain boat. Put it into a tubular furnace and set the heating rate to 5℃ / min under a nitrogen atmosphere. Raise the temperature in the furnace to 850℃ and calcine for 3h. Cool it naturally to room temperature to obtain the ginkgo leaf carbon-based catalyst.
[0068] The prepared ginkgo leaf carbon-based catalyst was subjected to linear voltammetry and cyclic voltammetry tests using a rotating disk electrode apparatus to measure the catalytic activity of the catalyst using its half-wave potential and starting potential. Figure 1 and Figure 2 As shown, the half-wave potential and starting potential of the carbon-based catalyst prepared in this example are 0.8284V and 0.8631V. The data results are as follows Figure 1 and Figure 2 shown.
[0069] Example 4
[0070] This embodiment provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0071] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0072] 2. Take 1g of the pre-carbonized sample and 2g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 5℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 1h, then cool naturally to room temperature to obtain a mixed carbon sample for standby use.
[0073] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take a pH=1 concentrated nitric acid solution to adjust the solution to acidity and stir at a stirring rate of 500r / min for 8h to obtain an acidic solution of a certain concentration.
[0074] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain 0.14g of activated carbon sample.
[0075] 5. Weigh 0.05g activated carbon and 0.2g thiourea in a mortar, grind them thoroughly, mix them and put them into a porcelain boat. Put it into a tubular furnace and set the heating rate to 5℃ / min under a nitrogen atmosphere. Raise the temperature in the furnace to 850℃ and calcine for 3h. Cool it naturally to room temperature to obtain the ginkgo leaf carbon-based catalyst.
[0076] The prepared ginkgo leaf carbon-based catalyst was subjected to linear voltammetry and cyclic voltammetry tests using a rotating disk electrode apparatus to measure the catalytic activity of the catalyst using its half-wave potential and starting potential. Figure 1 and Figure 2 As shown, the catalyst half-wave potential and starting potential of the carbon-based catalyst prepared in this example are 0.8206V and 0.8567V, respectively. Figure 1 and Figure 2 shown.
[0077] Example 5
[0078] This embodiment provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0079] 1. Take 30g of ginkgo leaf powder and set the heating rate to 10℃ / min in a muffle furnace. Raise the temperature in the furnace to 500℃ and calcine for 1h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for standby use.
[0080] 2. Take 3.5g of the pre-carbonized sample and 5g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 10℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 900℃, calcine for 0.5h, and then cool naturally to room temperature to obtain a mixed carbon sample for stand-alone use.
[0081] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 12h to obtain an acidic solution of a certain concentration.
[0082] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain 0.53g of activated carbon sample.
[0083] 5. Weigh 0.5g activated carbon and 1.5g thiourea in a mortar, grind them thoroughly, mix them and put them into a porcelain boat. Put it into a tubular furnace and set the heating rate to 10℃ / min under a nitrogen atmosphere. Raise the temperature in the furnace to 700℃ and calcine for 5h. Cool it naturally to room temperature to obtain the ginkgo leaf carbon-based catalyst.
[0084] The prepared ginkgo leaf carbon-based catalyst was subjected to linear voltammetry test and cyclic voltammetry test using a rotating disk electrode device. Its half-wave potential and starting potential reflect the catalytic activity of the catalyst. The catalyst half-wave potential and starting potential of the carbon-based catalyst prepared in this example were 0.7534V and 0.8788V.
[0085] Comparative Example 1
[0086] This comparative example provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0087] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0088] 2. Take 1g of the pre-carbonized sample and 2g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 5℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 1h, then cool naturally to room temperature to obtain a mixed carbon sample for standby use.
[0089] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 8h to obtain an acidic solution of a certain concentration.
[0090] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain the ginkgo leaf carbon-based catalyst.
[0091] The prepared ginkgo leaf carbon-based catalyst was subjected to a linear voltammetric scan test using a rotating disk electrode device to reflect the catalytic activity of the catalyst with its half-wave potential. The results showed that the half-wave potential and starting potential of the catalyst under this scheme were 0.6362V and 0.7087V, respectively. The data results show that Figure 1 , and XRD test its doping, the data results can be seen Figure 7 The results of hydrogen peroxide generation rate and electron transfer number are shown in Figure 3 .
[0092] Comparative Example 2
[0093] This comparative example provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0094] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0095] 2. Take 1 g of the pre-carbonized sample, grind it thoroughly in a mortar, put it into a porcelain boat, and set the heating rate to 5°C / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800°C, calcine for 1 hour, and then cool naturally to room temperature to obtain a ginkgo leaf carbon-based catalyst.
[0096] The prepared Ginkgo biloba carbon-based catalyst was subjected to a linear voltammetric scan test using a rotating disk electrode device to measure the catalytic activity of the catalyst using its half-wave potential. Figure 1 As shown, the half-wave potential and starting potential of the carbon-based catalyst prepared in this example are 0.4678V and 0.641V. Figure 1 .
[0097] Comparative Example 3
[0098] This comparative example provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0099] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0100] 2. Take 1g of the pre-carbonized sample and 2g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 5℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 1h, then naturally cool to room temperature to obtain 3.72g of a mixed carbon sample.
[0101] 3. Take 3.72 g of the mixed carbon sample and add an appropriate amount of deionized water to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain the ginkgo leaf carbon-based catalyst.
[0102] The sample was tested for doping by XRD, and the data results can be seen Figure 7 ,from Figure 7 It can be seen that without acid treatment, the obtained carbon-based catalyst contains a large number of impurity peaks, that is, it contains a variety of impurities, which will lead to poor conductivity.
[0103] Comparative Example 4
[0104] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0105] 2. Take 1g of the pre-carbonized sample, 2g of potassium hydroxide and 0.28g of thiourea, grind them thoroughly in a mortar and mix them. Then put them into a porcelain boat and place them in a tubular furnace in a nitrogen atmosphere. Set the heating rate to 5℃ / min, raise the temperature in the furnace to 800℃, calcine for 1h, and then naturally cool to room temperature to obtain 3g of mixed carbon sample.
[0106] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 8h to obtain an acidic solution of a certain concentration.
[0107] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it by suction, and put the wet carbon into an oven to dry to obtain 0.1g of ginkgo leaf carbon-based catalyst.
[0108] The prepared ginkgo leaf carbon-based catalyst was subjected to linear voltammetry and cyclic voltammetry tests using a rotating disk electrode apparatus to measure the catalytic activity of the catalyst using its half-wave potential and starting potential. Figure 1 and Figure 2 As shown, the catalyst half-wave potential and starting potential of the carbon-based catalyst prepared in this example are 0.7402V and 0.8537V.
[0109] From the description in the aforementioned Example 2, it can be seen that the mixed carbon sample obtained after calcining 1g of the carbonized sample and 2g of potassium hydroxide in Step 2 is about 0.14g. Therefore, the ratio of the mixed carbon sample and thiourea in this comparative example is the same as that in Example 2.
[0110] Comparative Example 5
[0111] This embodiment provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0112] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0113] 2. Take 1g of the pre-carbonized sample and 2g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 5℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 1h, then cool naturally to room temperature to obtain a mixed carbon sample for standby use.
[0114] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 8h to obtain an acidic solution of a certain concentration.
[0115] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain 0.14g of activated carbon sample.
[0116] 5. Weigh 0.05g activated carbon and 0.25g thiourea in a mortar, grind them thoroughly and mix them into a porcelain boat. Put it into a tubular furnace and set the heating rate to 5℃ / min under a nitrogen atmosphere. Raise the temperature in the furnace to 850℃ and calcine for 3h. Cool it naturally to room temperature to obtain the ginkgo leaf carbon-based catalyst.
[0117] The prepared ginkgo leaf carbon-based catalyst was subjected to linear voltammetry and cyclic voltammetry tests using a rotating disk electrode apparatus to measure the catalytic activity of the catalyst using its half-wave potential and starting potential. Figure 1 and Figure 2 As shown, the catalyst half-wave potential and starting potential of the carbon-based catalyst prepared in this example are 0.6710V and 0.7654V.
[0118] Comparative Example 6
[0119] This embodiment provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0120] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0121] 2. Take 1g of the pre-carbonized sample and 2g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 5℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 1h, then cool naturally to room temperature to obtain a mixed carbon sample for standby use.
[0122] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 8h to obtain an acidic solution of a certain concentration.
[0123] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain 0.14g of activated carbon sample.
[0124] 5. Weigh 0.05g activated carbon and 0.25g thiourea in a mortar, grind them thoroughly and mix them into a porcelain boat. Put it into a tubular furnace and set the heating rate to 5℃ / min under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 3h. Cool it naturally to room temperature to obtain the ginkgo leaf carbon-based catalyst.
[0125] The prepared Ginkgo biloba carbon-based catalyst was subjected to a linear voltammetric scan test using a rotating disk electrode device to measure the catalytic activity of the catalyst using its half-wave potential. Figure 1 and Figure 2As shown, the catalyst half-wave potential and starting potential of the carbon-based catalyst prepared in this example are 0.6742V and 0.7497V.
[0126] Comparative Example 7
[0127] This embodiment provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0128] 1. Take 30g of ginkgo leaf powder and set the heating rate to 5℃ / min in a muffle furnace. Raise the temperature in the furnace to 400℃ and calcine for 2h. Finally, cool naturally to room temperature to obtain 15g of pre-carbonized sample for stand-by use.
[0129] 2. Take 1g of the pre-carbonized sample and 2g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 5℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 800℃ and calcine for 1h, then cool naturally to room temperature to obtain a mixed carbon sample for standby use.
[0130] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 8h to obtain an acidic solution of a certain concentration.
[0131] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain 0.14g of activated carbon sample.
[0132] 5. Weigh 0.05g activated carbon and 0.25g thiourea in a mortar, grind them thoroughly and mix them into a porcelain boat. Put it into a tubular furnace and set the heating rate to 5℃ / min under a nitrogen atmosphere. Raise the temperature in the furnace to 900℃ and calcine for 3h. Cool it naturally to room temperature to obtain the ginkgo leaf carbon-based catalyst.
[0133] The prepared Ginkgo biloba carbon-based catalyst was subjected to a linear voltammetric scan test using a rotating disk electrode device to measure the catalytic activity of the catalyst using its half-wave potential. Figure 1 and Figure 2 As shown, the catalyst half-wave potential and starting potential of the carbon-based catalyst prepared in this example are 0.7702V and 0.8079V.
[0134] Comparative Example 8
[0135] This embodiment provides a carbon-based catalyst based on ginkgo leaves, and the specific preparation method is as follows:
[0136] 1. Take 30g of ginkgo leaf powder and set the heating rate to 3℃ / min in a muffle furnace. Raise the temperature in the furnace to 200℃ and calcine for 4h. Finally, cool naturally to room temperature to obtain 10g of pre-carbonized sample for stand-by use.
[0137] 2. Take 0.5g of the pre-carbonized sample and 0.8g of potassium hydroxide, grind and mix them thoroughly in a mortar, put them into a porcelain boat, and set the heating rate to 3℃ / min in a tubular furnace under a nitrogen atmosphere. Raise the temperature in the furnace to 700℃ and calcine for 3h, then cool naturally to room temperature to obtain a mixed carbon sample for stand-alone use.
[0138] 3. Take the mixed carbon sample in a 500mL beaker, add 500mL deionized water, take concentrated nitric acid solution to adjust the solution to pH = 1 and stir at a stirring rate of 500r / min for 6h to obtain an acidic solution of a certain concentration.
[0139] 4. Add an appropriate amount of deionized water to the acidic solution to wash the solution to neutrality. After obtaining the neutral solution, filter it and put the wet carbon into an oven to dry to obtain 0.65g of activated carbon sample.
[0140] 5. Weigh 0.01g activated carbon and 0.04g thiourea in a mortar, grind them thoroughly and mix them into a porcelain boat. Put it into a tubular furnace and set the heating rate to 3℃ / min under a nitrogen atmosphere. Raise the temperature in the furnace to 700℃ and calcine for 5h. Cool it naturally to room temperature to obtain the ginkgo leaf carbon-based catalyst.
[0141] The prepared ginkgo leaf carbon-based catalyst was subjected to linear voltammetry test and cyclic voltammetry test using a rotating disk electrode device. Its half-wave potential and starting potential reflect the catalytic activity of the catalyst. The catalyst half-wave potential and starting potential of the carbon-based catalyst prepared in this example were 0.745V and 0.7529V.
[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A carbon-based catalyst, characterized in that The invention is prepared from raw materials including the following components: ginkgo leaves, metal hydroxide and nitrogen-containing compound; In parts by weight, the ginkgo leaf is 1 to 10 parts, the metal hydroxide is 1 to 10 parts, and the nitrogen-containing compound is 0.05 to 2 parts.
2. The carbon-based catalyst according to claim 1, characterized in that The raw materials also include acid and water.
3. The carbon-based catalyst according to claim 1 or 2, characterized in that The metal hydroxide includes one or more of potassium hydroxide and sodium hydroxide.
4. The carbon-based catalyst according to claim 1 or 2, characterized in that The nitrogen-containing compound includes one or more of thiourea, melamine or urea.
5. A method for preparing a carbon-based catalyst, characterized in that: include: Based on Ginkgo biloba leaves, carbonization, pH neutralization and nitrogen hybridization were carried out; Metal hydroxide is added during the carbonization process.
6. The preparation method according to claim 5, characterized in that: The carbonization treatment comprises: placing the ginkgo leaves under a temperature increase condition of 3°C / min to 10°C / min and heating them to 200°C to 500°C for 1 to 4 hours to obtain a pre-carbonized sample; The pre-carbonized sample and the metal hydroxide are mixed, and the mixture is heated to 700° C. to 900° C. at a temperature of 3° C. / min to 10° C. / min for 0.5 h to 3 h, and then cooled to 20 to 30° C. to obtain a mixed carbon sample.
7. The preparation method according to claim 5 or 6, characterized in that: The pH neutralization comprises: The mixed carbon sample prepared by the carbonization treatment is placed in water to obtain a suspension; the pH value of the suspension is adjusted to acidic with an acid and stirred for 6 to 12 hours to obtain an acidic suspension; the acidic suspension is washed to neutral with water, then filtered and dried to obtain an activated carbon sample.
8. The preparation method according to claim 5, characterized in that: The nitrogen hybridization treatment comprises: The activated carbon sample obtained by pH neutralization and the nitrogen-containing compound are mixed and heated to 700°C to 1000°C at a temperature of 3°C / min to 10°C / min for 1 to 5 hours, and then cooled to 20 to 30°C; Preferably, the mass ratio of the activated carbon sample to the nitrogen-containing compound is 1:(0.5-5).
9. The carbon-based catalyst prepared by the preparation method according to any one of claims 5 to 8.
10. Use of the carbon-based catalyst according to any one of claims 1 to 4, or the carbon-based catalyst according to claim 9 in a fuel cell and a metal-air battery.