A nano SnO x Modified pdsn catalyst, method for preparing hydrogen sensing electrode and electrochemical sensor application

Abstract

This invention discloses a nano-SnO x The preparation method of the modified PdSn catalyst and hydrogen sensing electrode, and their application in electrochemical sensors, belong to the fields of nanocatalytic materials and gas sensing technology. The hydrogen sensing electrode is a nano-SnO coated on the surface of a perfluorosulfonic acid resin film. x Modified PdSn catalyst layer. The preparation method includes: dispersing palladium salt, tin salt, and reducing agent in an organic solvent, reacting at 80-250℃, and obtaining nano-SnO after centrifugation, washing, and drying. x Modified PdSn catalyst; the catalyst was mixed with water, ethanol, and ionomer, and coated onto the surface of a perfluorosulfonic acid resin membrane to obtain a nano-SnO-based catalyst. x Hydrogen sensing electrode based on modified PdSn catalyst. x The sensing electrode of the modified PdSn catalyst exhibits excellent performance in hydrogen sensors, including short response time and resistance to carbon monoxide poisoning, providing a practical technical route for high-efficiency hydrogen sensing materials.

Description

Technical Field

[0001] This invention belongs to the field of nanocatalytic materials and electrochemical gas sensing technology, specifically relating to a method for preparing PdSn spherical nanoparticle catalysts and hydrogen sensing electrodes and their application in electrochemical sensors. Background Technology

[0002] In the energy sector, hydrogen energy shows great potential as an emerging alternative energy source, but its safety remains a crucial issue. Compared to traditional energy carriers (such as gasoline, kerosene, diesel, natural gas, electricity, and coal), public awareness of hydrogen energy is relatively low, leading to potential concerns about its safety. As a flammable and explosive gas, hydrogen has an explosive limit of 4%-74.2%. This characteristic creates significant safety hazards at every stage of the hydrogen energy industry chain, potentially leading to major accidents during preparation, storage, refueling, and application. Any catastrophic event could have a disruptive impact on the entire industry. To address these potential risks, hydrogen sensors have emerged as an important safety device. They can detect hydrogen leaks in the air in a timely manner and alert operators to check and take evasive action by issuing alarm signals. Various models of these sensors are available on the market, each with its own unique working principle, but core indicators such as sensitivity and response time are common.

[0003] However, these sensors also face significant challenges in complex and ever-changing real-world applications. For example, in environments containing other polluting gases (such as carbon monoxide), hydrogen sensors may be affected, leading to a significant reduction in their response signal. Therefore, continued research and technological breakthroughs are still needed to improve the sensors' resistance to CO poisoning and shorten their response time.

[0004] The key to sensor performance lies in the performance of the hydrogen sensing material (catalyst). Commonly used catalysts for hydrogen sensing are primarily Pd-based materials. Strategies to shorten response time mainly include alloying with other metals, reducing catalyst particle size, and utilizing metal-support interactions (ACS Sensors., 2019, 4, 1424). 1432, Nature Materials, 2019, 18, 489-495; Sensors and Actuators, B: Chemical, 2023, 387, 133790. Strategies to improve catalyst resistance to CO poisoning mainly include alloying with other metals, utilizing metal-support interactions, and gas filtration layers (Chem, 2020, 6, 2746-2758; Sensors and Actuators, B: Chemical, 2024, 416, 136022-136028; ACS Applied Materials & Interfaces, 2015, 7, 3554). (3561), among which alloying is the simplest and most effective, with the advantage of simultaneously optimizing response time and resistance to CO poisoning. However, it still generally suffers from problems such as long response time (90-120s) and insufficient resistance to CO poisoning.

[0005] Therefore, in order to shorten the response time of hydrogen sensors and improve their resistance to CO poisoning, it is necessary to develop a nano-SnO material for hydrogen sensors. x Modified PdSn catalyst and hydrogen sensing electrode. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems in the prior art and provide a nano-SnO x Preparation method of modified PdSn catalyst and hydrogen sensing electrode and its application in electrochemical sensors; preparation of nano-SnO x The modified PdSn catalyst and hydrogen sensing electrode exhibit rapid response and resistance to CO poisoning.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A nano-SnO x The method for preparing the modified PdSn catalyst includes the following steps: Palladium salt, tin salt, and reducing agent were dispersed in an organic solvent and reacted for a certain time under specific temperature and stirring conditions. After centrifugation and washing with a cleaning agent and drying, nano-SnO was obtained. x Modified PdSn catalyst.

[0009] Furthermore, the concentration of the palladium salt in the organic solvent is 10-500 mmol / L, preferably 40-100 mmol / L, more preferably 50 mmol / L; the concentration of the tin salt in the organic solvent is 5-300 mmol / L, preferably 25-50 mmol / L, more preferably 50 mmol / L; and the concentration of the reducing agent in the organic solvent is 30-1500 mmol / L, preferably 150-300 mmol / L, more preferably 200 mmol / L.

[0010] Furthermore, the palladium salt is one of palladium acetylacetonate, potassium palladium chloride, palladium chloride, sodium palladium chloride, palladium acetate, dichlorotetramine palladium, palladium nitrate, and palladium sulfate.

[0011] Furthermore, the tin salt is one of tin acetylacetonate, tin acetate, tin sulfate, tin tetrachloride, and tin oxalate.

[0012] Furthermore, the reducing agent is one of glucose, maltose, ribose, methanol, formaldehyde, formic acid, benzyl alcohol, ascorbic acid, sodium borohydride, polyol, oxalic acid, and molybdenum hexacarbonyl.

[0013] Furthermore, the organic solvent is one or more of oleylamine, octadecene, methanol, ethanol, ethylene glycol, propanol, butanol, pentanol, oleic acid, and dodecylamine, preferably a mixed solvent of oleylamine and octadecene; the volume ratio of oleylamine to octadecene in the mixed solvent of oleylamine and octadecene is 0.5-2:1, preferably 1:1.

[0014] Furthermore, the reaction conditions are as follows: the reaction temperature is 80-250℃, preferably 120-200℃, more preferably 150-180℃; the reaction time is 0.5-24h, preferably 1-12h, more preferably 6h; and the stirring speed is 100-900rpm, preferably 300-600rpm, more preferably 500rpm.

[0015] Furthermore, the cleaning agent is a mixture of ethanol and cyclohexane, and a mixture of ethanol and water. The centrifugal washing method is as follows: under certain speed conditions, the mixture of ethanol and cyclohexane is centrifuged and washed 3-5 times, and then the mixture of ethanol and water is centrifuged and washed 3-5 times. The speed is 8000-11000 rpm, preferably 10000 rpm; the volume ratio of ethanol to cyclohexane in the ethanol and cyclohexane mixture is 10-2:1, preferably 5:1; the volume ratio of ethanol to water in the ethanol and water mixture is 10-2:1, preferably 5:1; the centrifugation time is 3-10 min, preferably 5 min.

[0016] Furthermore, the drying temperature is -50-90℃, preferably 60-80℃, more preferably 65℃; the drying time is 1-72h, preferably 6-24h, more preferably 12h.

[0017] This invention also relates to protecting the nano-SnO prepared by the above-described preparation method. x Modified PdSn catalyst. The catalyst is a PdSn nanoparticle encapsulated in tin oxide nanoparticles, which are spherical particles with a PdSn nanoparticle size of 3-10 nm. x It is an amorphous or weakly crystalline nano-oxide, with a palladium content of 50-95 wt., preferably 80-90 wt., and a tin content of 5-50 wt., preferably 10-20 wt.

[0018] A method based on the above-mentioned nano-SnO x The method for preparing a hydrogen sensing electrode with modified PdSn catalyst includes the following steps: Nano SnO x The modified PdSn catalyst was mixed with water, ethanol, and ionomer in a certain proportion to prepare a catalyst slurry. The slurry was then sprayed onto the surface of a perfluorosulfonic acid resin membrane to obtain a catalyst layer, which is nano-SnO. x Hydrogen sensing electrode with modified PdSn catalyst.

[0019] Furthermore, the water is deionized water, the ethanol is anhydrous ethanol, and the ionomer is perfluorosulfonic acid resin.

[0020] Furthermore, the ionomer is used as an ionomer solution, preferably a 5-10 wt.% Nafion solution. The volume ratio of water, anhydrous ethanol, and the ionomer solution is 1:9:(0-0.5), preferably 1:9:0.05.

[0021] Furthermore, the concentration of the catalyst in the catalyst slurry is 0.1-2 mg / ml, preferably 1 mg / ml.

[0022] Furthermore, the coating conditions are as follows: the catalyst slurry is sprayed onto a perfluorosulfonic acid resin membrane (e.g., Nafion 211 membrane) on a vacuum heating platform at 60-85°C to obtain a catalyst layer, which is the hydrogen sensing electrode.

[0023] Furthermore, the electrode area is 0.04-4 cm². 2 Preferably 1cm 2 .

[0024] Furthermore, the catalyst loading in the catalyst layer is 0.01-2 mg / cm³. 2 Preferably 0.1 mg / cm 2 .

[0025] The present invention also provides the above-mentioned nano-SnO-based x Application of modified PdSn catalyst hydrogen sensing electrode in electrochemical hydrogen sensor.

[0026] Furthermore, the application includes the following steps: The membrane electrode was obtained by stacking the gas diffusion layer, catalyst layer, and perfluorosulfonic acid resin membrane in that order and hot-pressing them. Finally, the membrane electrode was connected to the current collector of the hydrogen sensor and assembled into the hydrogen sensor to obtain nano-SnO. x Hydrogen sensor based on modified PdSn catalyst.

[0027] Furthermore, the gas diffusion layer includes carbon paper, carbon cloth, carbon fiber, carbon black paper, titanium mesh, nickel mesh, platinum mesh, gold mesh, stainless steel mesh, or carbon paper, carbon cloth, carbon fiber, carbon black paper, titanium mesh, nickel mesh, platinum mesh, gold mesh, stainless steel mesh covered with a microporous layer, wherein the material of the microporous layer includes VXC. 72. EC 600, BP Carbon black of model 2000.

[0028] Furthermore, the perfluorosulfonic acid resin membrane includes Nafion membranes and Gore membranes, such as Nafion 211 membrane, Nafion 212 membrane, Nafion 115 membrane, Nafion 117 membrane, Gore 8μm membrane, Gore 12μm membrane, Gore 15μm membrane, and Gore 18μm membrane.

[0029] Furthermore, the hot pressing conditions are: 120-140℃ and 0.1-2MPa for 1-5 minutes.

[0030] Furthermore, the H2 concentration in the hydrogen sensor test is 500 ppm H2 / air, and the test gas used in the CO poisoning resistance test is (50 ppm CO + 1000 ppm H2) / air.

[0031] Compared with existing technologies, the advantages of the technical solution of this invention are: This invention relates to nano-SnO x The modified PdSn catalyst and hydrogen sensing electrode exhibit a fast response speed in the hydrogen sensor, with a response time of 2.2 seconds, while the response time of the hydrogen sensor based on the Pd black catalyst is 103.3 seconds; nano-SnO x The modified PdSn catalyst exhibits improved CO poisoning resistance in hydrogen sensors, achieving better performance when 50 ppm CO is present in 1000 ppm H2 / air, based on nano-SnO. xThe hydrogen sensor response signal of the modified PdSn catalyst decreased by 3.6%, while the hydrogen sensor response current based on the Pd black catalyst decreased by 16.7%, indicating that nano-SnO... x The modified PdSn catalyst and hydrogen sensing electrode exhibit faster response speed and better resistance to CO poisoning, demonstrating excellent hydrogen sensing performance.

[0032] This invention utilizes an organic liquid-phase reduction method to obtain nano-SnO through a one-step reduction, centrifugation, washing, and drying process. x Modified PdSn catalysts have a simple preparation process, short cycle time, and wide applicability.

[0033] This invention relates to nano-SnO x Modified PdSn catalysts and hydrogen sensing electrodes provide a practical technical route for high-efficiency hydrogen sensing materials. Attached Figure Description

[0034] Figure 1 Example 1 shows the preparation of nano-SnO. x Transmission electron microscopy (TEM) spectra of the modified PdSn catalyst.

[0035] Figure 2 Example 1 shows the preparation of nano-SnO. x Particle size distribution of the modified PdSn catalyst sample.

[0036] Figure 3 Example 1 shows the preparation of nano-SnO. x High-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) image of the modified PdSn catalyst sample.

[0037] Figure 4 Example 1 shows the preparation of nano-SnO. x Scanning electron microscopy (SEM) image of a hydrogen sensing electrode sample with modified PdSn catalyst.

[0038] Figure 5 Example 1 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst.

[0039] Figure 6 Example 1 shows the preparation of nano-SnO-based materials. x Response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air.

[0040] Figure 7 Example 1 shows the preparation of nano-SnO-based materials. xThe pulse response curves of the hydrogen sensor with modified PdSn catalyst were obtained by repeated measurements under a hydrogen concentration of 500 ppm H2 / air.

[0041] Figure 8 Example 1 shows the preparation of nano-SnO-based materials. x The graph shows the CO poisoning resistance of the modified PdSn catalyst as measured by a hydrogen sensor under (50ppmCO + 1000ppmH2) / air conditions.

[0042] Figure 9 Example 2 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst.

[0043] Figure 10 Example 2 shows the preparation of nano-SnO-based materials. x Response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air.

[0044] Figure 11 Example 2 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor with modified PdSn catalyst were obtained by repeated measurements under a hydrogen concentration of 500 ppm H2 / air.

[0045] Figure 12 Example 2 shows the preparation of nano-SnO-based materials. x The graph shows the CO poisoning resistance of the modified PdSn catalyst as measured by a hydrogen sensor under (50ppmCO + 1000ppmH2) / air conditions.

[0046] Figure 13 Example 3 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst.

[0047] Figure 14 Example 3 shows the preparation of nano-SnO-based materials. x Response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air.

[0048] Figure 15 Example 3 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor with modified PdSn catalyst were obtained by repeated measurements under a hydrogen concentration of 500 ppm H2 / air.

[0049] Figure 16 Example 3 shows the preparation of nano-SnO-based materials. xThe graph shows the CO poisoning resistance of the modified PdSn catalyst as measured by a hydrogen sensor under (50ppmCO + 1000ppmH2) / air conditions.

[0050] Figure 17 Example 4 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst.

[0051] Figure 18 Example 4 shows the preparation of nano-SnO-based materials. x Response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air.

[0052] Figure 19 Example 4 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor with modified PdSn catalyst were obtained by repeated measurements under a hydrogen concentration of 500 ppm H2 / air.

[0053] Figure 20 Example 4 shows the preparation of nano-SnO-based materials. x The graph shows the CO poisoning resistance of the modified PdSn catalyst as measured by a hydrogen sensor under (50ppmCO + 1000ppmH2) / air conditions.

[0054] Figure 21 Example 5 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst.

[0055] Figure 22 Example 5 shows the preparation of nano-SnO-based materials. x Response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air.

[0056] Figure 23 Example 5 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor with modified PdSn catalyst were obtained by repeated measurements under a hydrogen concentration of 500 ppm H2 / air.

[0057] Figure 24 Example 5 shows the preparation of nano-SnO-based materials. x The graph shows the CO poisoning resistance of the modified PdSn catalyst as measured by a hydrogen sensor under (50ppmCO + 1000ppmH2) / air conditions.

[0058] Figure 25 Example 6 shows the preparation of nano-SnO-based materials. xX-ray diffraction (XRD) pattern of the modified PdSn catalyst.

[0059] Figure 26 Example 6 shows the preparation of nano-SnO-based materials. x Response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air.

[0060] Figure 27 Example 6 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor with modified PdSn catalyst were obtained by repeated measurements under a hydrogen concentration of 500 ppm H2 / air.

[0061] Figure 28 Example 6 shows the preparation of nano-SnO-based materials. x The graph shows the CO poisoning resistance of the modified PdSn catalyst as measured by a hydrogen sensor under (50ppmCO + 1000ppmH2) / air conditions.

[0062] Figure 29 The X-ray diffraction (XRD) patterns of Pd black catalysts prepared in a comparative manner are shown.

[0063] Figure 30 This is a graph showing the response time analysis of a Pd black catalyst-based hydrogen sensor prepared in a comparative manner at a hydrogen concentration of 500 ppm H2 / air.

[0064] Figure 31 This is a graph showing the CO poisoning resistance of a Pd black catalyst-based hydrogen sensor prepared in a comparative manner under (50ppmCO+1000ppmH2) / air conditions. Detailed Implementation

[0065] The following embodiments will further illustrate the present invention, but are not intended to limit the invention.

[0066] Example 1 2 mmol of glucose, 0.5 mmol of tin acetylacetonate, and 0.5 mmol of potassium palladium chloride were uniformly dispersed in 5 ml of oleylamine and 5 ml of octadecene. The mixture was then reacted at 150 °C and 500 rpm for 6 h with stirring, followed by cooling to room temperature. The mixture was then centrifuged and washed three times with a 5:1 mixture of ethanol and cyclohexane at 10,000 rpm, followed by three more centrifugations with a 5:1 mixture of ethanol and water. After centrifugal purification, the mixture was dried in a 65 °C oven for 12 h. The resulting black catalyst powder was nano-SnO. x A modified PdSn catalyst. The catalyst contains 80.5 wt.% Pd and 19.5 wt.% Sn.

[0067] Prepared nano-SnO x The modified PdSn catalyst was dispersed in a mixed solution of deionized water, anhydrous ethanol, and ionomer (perfluorosulfonic acid resin: Nafion solution, 5 wt.%) to prepare a slurry with a concentration of 1 mg / ml. The volume ratio of deionized water, anhydrous ethanol, and Nafion solution was 1:9:0.05. The catalyst slurry was then uniformly sprayed onto a perfluorosulfonic acid resin membrane (Nafion 211 membrane) on a vacuum heating platform at 80°C to obtain a catalyst loading of 0.1 mg / cm³. 2 The catalyst layer, namely based on nano-SnO x Hydrogen sensing electrode with modified PdSn catalyst.

[0068] A membrane electrode was obtained by stacking a gas diffusion layer (carbon paper), a catalyst layer (hydrogen sensing electrode), and a perfluorosulfonic acid resin membrane (Nafion 211 membrane) in that order and hot-pressing it at 130℃ and 0.15MPa for 2 min. Finally, the membrane electrode was connected to the current collector of the hydrogen sensor and assembled into the hydrogen sensor, resulting in a nano-SnO-based electrode. x Hydrogen sensor based on modified PdSn catalyst.

[0069] Figure 1 Example 1 shows the preparation of nano-SnO. x Transmission electron microscopy (TEM) image of the modified PdSn catalyst. TEM shows nano-SnO. x The modified PdSn catalyst particles are uniformly sized spherical particles and do not exhibit significant agglomeration.

[0070] Figure 2 Example 1 shows the preparation of nano-SnO. x Particle size distribution of the modified PdSn catalyst sample. The particle size distribution shows that nano-SnO x The modified PdSn catalyst particles have a particle size of 5.30 ± 0.60 nm.

[0071] Figure 3 Example 1 shows the preparation of nano-SnO. x High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images of the modified PdSn catalyst samples. In the HAADF-STEM images, the region with a lattice spacing of 0.233 nm corresponds to the (111) crystal plane of the PdSn alloy nanoparticles, while the regions with lattice spacings of 0.34 nm and 0.27 nm correspond to Sn oxides. The oxides are mainly distributed around the PdSn nanoparticles. The results indicate that nano-SnO… x Successful preparation of modified PdSn catalyst.

[0072] Figure 4Example 1 shows the preparation of nano-SnO-based materials. x Scanning electron microscopy (SEM) image of the hydrogen sensing electrode sample with modified PdSn catalyst. SEM reveals the presence of nano-SnO. x The modified PdSn catalyst was uniformly distributed on the surface of the perfluorosulfonic acid resin membrane (Nafion211 membrane).

[0073] Figure 5 Example 1 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst. XRD shows that the diffraction peaks of the catalyst correspond to those of Pd (PDF#87-0643), indicating that the introduction of Sn into the PdSn nanoparticles did not significantly alter the Pd crystal structure, which remains face-centered cubic, and no obvious SnO was observed. x The diffraction peaks suggest that SnO x It exists in a weakly crystalline form.

[0074] Figure 6 Example 1 shows the preparation of nano-SnO-based materials. x The response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air is shown in the figure. As shown, when the test gas of 500 ppm H2 / air is introduced at time (X-axis) 0 s, the relative response current (Y-axis) of the sensor reaches 90% after 2.2 s; this time is the response time. Based on nano-SnO... x The hydrogen sensor response time of the modified PdSn catalyst is 2.2 s.

[0075] Figure 7 Example 1 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor based on the modified PdSn catalyst were measured six times under a hydrogen concentration of 500 ppm H2 / air. The specific test procedure was as follows: the sensor was kept in an air atmosphere (blank area in the figure) for 2 minutes, then switched to a 500 ppm H2 / air atmosphere (gray area) for 4 minutes, then switched back to an air atmosphere for 2 minutes… This cycle was repeated six times to complete the test. The results showed that the response current of the sensor was basically consistent throughout the six tests, indicating that the sensor has good repeatability.

[0076] Figure 8 Example 1 shows the preparation of nano-SnO-based materials. xThe hydrogen sensor based on the modified PdSn catalyst exhibits CO poisoning resistance under (50 ppm CO + 1000 ppm H2) / air conditions. After being exposed to the (50 ppm CO + 1000 ppm H2) / air atmosphere for approximately 6 minutes, the sensor's response current value decreased to 96.4%, a decrease of only 3.6%. This indicates that the performance of the hydrogen sensor based on nano-SnO is relatively stable. x The hydrogen sensor based on the modified PdSn catalyst exhibits good resistance to CO poisoning.

[0077] Example 2 2 mmol ribose, 0.5 mmol tin acetate, and 0.5 mmol palladium chloride were uniformly dispersed in 5 ml oleylamine and 5 ml octadecene. The mixture was then reacted at 130 °C and 500 rpm for 6 h with stirring, followed by cooling to room temperature. The mixture was then centrifuged and washed three times with a 5:1 mixture of ethanol and cyclohexane at 10,000 rpm, followed by three more centrifugations with a 5:1 mixture of ethanol and water. After centrifugal purification, the mixture was dried in a 65 °C oven for 12 h. The resulting black catalyst powder was nano-SnO. x A modified PdSn catalyst with a Pd content of 81.3 wt.% and a Sn content of 18.7 wt.%.

[0078] Following the method in Example 1, nano-SnO x The modified PdSn catalyst was used to prepare a hydrogen sensing electrode and a hydrogen sensor.

[0079] Figure 9 Example 2 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst. XRD shows that the diffraction peaks of the catalyst correspond to those of Pd (PDF#87-0643), indicating that the introduction of Sn into the PdSn nanoparticles did not significantly alter the Pd crystal structure, which remains face-centered cubic, and no obvious SnO was observed. x The diffraction peaks suggest that SnO x It exists in a weakly crystalline form.

[0080] Figure 10 Example 2 shows the preparation of nano-SnO-based materials. x The response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air is shown in the figure. As shown, when the test gas of 500 ppm H2 / air is introduced at time (X-axis) 0 s, the relative response current (Y-axis) of the sensor reaches 90% after 73.5 s; this time is the response time. Based on nano-SnO... x The hydrogen sensor response time of the modified PdSn catalyst is 73.5 s.

[0081] Figure 11 Example 2 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor based on the modified PdSn catalyst were measured six times under a hydrogen concentration of 500 ppm H2 / air. The specific test procedure was as follows: the sensor was kept in an air atmosphere (blank area in the figure) for 2 minutes, then switched to a 500 ppm H2 / air atmosphere (gray area) for 4 minutes, then switched back to an air atmosphere for 2 minutes… This cycle was repeated six times to complete the test. The results showed that the response current of the sensor was basically consistent throughout the six tests, indicating that the sensor has good repeatability.

[0082] Figure 12 Example 2 shows the preparation of nano-SnO-based materials. x The hydrogen sensor based on the modified PdSn catalyst exhibits CO poisoning resistance under (50 ppm CO + 1000 ppm H2) / air conditions. After being exposed to the (50 ppm CO + 1000 ppm H2) / air atmosphere for approximately 6 minutes, the sensor's response current value decreased to 95.3%, a decrease of only 4.7%. This indicates that the performance of the hydrogen sensor based on nano-SnO is relatively stable. x The hydrogen sensor based on the modified PdSn catalyst exhibits good resistance to CO poisoning.

[0083] Example 3 2 mmol maltose, 0.5 mmol tin acetylacetonate, and 0.5 mmol palladium acetylacetonate were uniformly dispersed in 5 ml oleylamine and 5 ml octadecene. The mixture was then reacted at 160 °C and 500 rpm for 3 h with stirring, followed by cooling to room temperature. The mixture was then centrifuged and washed three times with a 5:1 mixture of ethanol and cyclohexane at 10,000 rpm, followed by three more centrifugations with a 5:1 mixture of ethanol and water. After centrifugal purification, the mixture was dried in a 65 °C oven for 12 h. The resulting black catalyst powder was nano-SnO. x A modified PdSn catalyst. The catalyst contains 83.4 wt.% Pd and 16.6 wt.% Sn.

[0084] Following the method in Example 1, nano-SnO x The modified PdSn catalyst was used to prepare a hydrogen sensing electrode and a hydrogen sensor.

[0085] Figure 13 Example 3 shows the preparation of nano-SnO-based materials. xX-ray diffraction (XRD) pattern of the modified PdSn catalyst. XRD shows that the diffraction peaks of the catalyst correspond to those of Pd (PDF#87-0643), indicating that the introduction of Sn into the PdSn nanoparticles did not significantly alter the Pd crystal structure, which remains face-centered cubic, and no obvious SnO was observed. x The diffraction peaks suggest that SnO x It exists in a weakly crystalline form.

[0086] Figure 14 Example 3 shows the preparation of nano-SnO-based materials. x The response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air is shown in the figure. As shown, when the test gas of 500 ppm H2 / air is introduced at time (X-axis) 0 s, the relative response current (Y-axis) of the sensor reaches 90% after 61.6 s; this time is the response time. Based on nano-SnO... x The hydrogen sensor response time of the modified PdSn catalyst is 61.6 s.

[0087] Figure 15 Example 3 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor based on the modified PdSn catalyst were measured six times under a hydrogen concentration of 500 ppm H2 / air. The specific test procedure was as follows: the sensor was kept in an air atmosphere (blank area in the figure) for 2 minutes, then switched to a 500 ppm H2 / air atmosphere (gray area) for 4 minutes, then switched back to an air atmosphere for 2 minutes… This cycle was repeated six times to complete the test. The results showed that the response current of the sensor was basically consistent throughout the six tests, indicating that the sensor has good repeatability.

[0088] Figure 16 Example 3 shows the preparation of nano-SnO-based materials. x The hydrogen sensor based on the modified PdSn catalyst exhibits CO poisoning resistance under (50 ppm CO + 1000 ppm H2) / air conditions. After being exposed to the (50 ppm CO + 1000 ppm H2) / air atmosphere for approximately 6 minutes, the sensor's response current value decreased to 95.8%, with a decrease of only 4.2%. This indicates that the performance of the hydrogen sensor based on nano-SnO is relatively stable. x The hydrogen sensor based on the modified PdSn catalyst exhibits good resistance to CO poisoning.

[0089] Example 4 2 mmol of molybdenum hexacarbonyl, 0.5 mmol of tin sulfate, and 0.5 mmol of palladium sulfate were uniformly dispersed in 5 ml of oleylamine and 5 ml of octadecene. The mixture was then reacted at 160 °C and 500 rpm for 6 h with stirring, followed by cooling to room temperature. The mixture was then centrifuged and washed three times with a 5:1 mixture of ethanol and cyclohexane at 10,000 rpm, followed by three more centrifugations with a 5:1 mixture of ethanol and water. After centrifugal purification, the mixture was dried in a 65 °C oven for 12 h. The resulting black catalyst powder was nano-SnO. x A modified PdSn catalyst. The catalyst contains 85.4 wt.% Pd and 14.5 wt.% Sn.

[0090] Following the method in Example 1, nano-SnO x The modified PdSn catalyst was used to prepare a hydrogen sensing electrode and a hydrogen sensor.

[0091] Figure 17 Example 4 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst. XRD shows that the diffraction peaks of the catalyst correspond to those of Pd (PDF#87-0643), indicating that the introduction of Sn into the PdSn nanoparticles did not significantly alter the Pd crystal structure, which remains face-centered cubic, and no obvious SnO was observed. x The diffraction peaks suggest that SnO x It exists in a weakly crystalline form.

[0092] Figure 18 Example 4 shows the preparation of nano-SnO-based materials. x The response time analysis of the hydrogen sensor based on the modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air is shown in the figure. As shown, when the test gas of 500 ppm H2 / air is introduced at time (X-axis) 0 s, the relative response current (Y-axis) of the sensor reaches 90% after 8.8 s; this time is the response time. Based on nano-SnO... x The hydrogen sensor response time of the modified PdSn catalyst is 8.8 s.

[0093] Figure 19 Example 4 shows the preparation of nano-SnO-based materials. xThe pulse response curves of the hydrogen sensor based on the modified PdSn catalyst were measured six times under a hydrogen concentration of 500 ppm H2 / air. The specific test procedure was as follows: the sensor was kept in an air atmosphere (blank area in the figure) for 2 minutes, then switched to a 500 ppm H2 / air atmosphere (gray area) for 4 minutes, then switched back to an air atmosphere for 2 minutes… This cycle was repeated six times to complete the test. The results showed that the response current of the sensor was basically consistent throughout the six tests, indicating that the sensor has good repeatability.

[0094] Figure 20 Example 4 shows the preparation of nano-SnO-based materials. x The hydrogen sensor based on the modified PdSn catalyst exhibits CO poisoning resistance under (50 ppm CO + 1000 ppm H2) / air conditions. After being exposed to the (50 ppm CO + 1000 ppm H2) / air atmosphere for approximately 6 minutes, the sensor's response current value decreased to 95.2%, with a decrease of only 14.8%. This indicates that the performance of the hydrogen sensor based on nano-SnO is relatively stable. x The hydrogen sensor based on the modified PdSn catalyst exhibits good resistance to CO poisoning.

[0095] Example 5 2 mmol of glucose, 0.5 mmol of tin acetate, and 0.5 mmol of potassium palladium chloride were uniformly dispersed in 10 ml of ethylene glycol. The mixture was then reacted at 180 °C and 500 rpm for 6 h with stirring. After cooling to room temperature, the mixture was washed three times by centrifugation with a 5:1 mixture of ethanol and cyclohexane at 10,000 rpm, followed by three more centrifugation washes with a 5:1 mixture of ethanol and water. After centrifugal purification, the mixture was dried in a 65 °C oven for 12 h. The resulting black catalyst powder was nano-SnO. x A modified PdSn catalyst. The catalyst contains 82.1 wt.% Pd and 17.9 wt.% Sn.

[0096] Following the method in Example 1, nano-SnO x The modified PdSn catalyst was used to prepare a hydrogen sensing electrode and a hydrogen sensor.

[0097] Figure 21 Example 5 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst. XRD shows that the diffraction peaks of the catalyst correspond to those of Pd (PDF#87-0643), indicating that the introduction of Sn into the PdSn nanoparticles did not significantly alter the Pd crystal structure, which remains face-centered cubic, and no obvious SnO was observed. x The diffraction peaks suggest that SnO xIt exists in a weakly crystalline form.

[0098] Figure 22 Example 5 shows the preparation of nano-SnO-based materials. x The response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air is shown in the figure. As shown, when the test gas of 500 ppm H2 / air is introduced at time (X-axis) 0 s, the relative response current (Y-axis) of the sensor reaches 90% after 44.4 s; this time is the response time. Based on nano-SnO... x The hydrogen sensor response time of the modified PdSn catalyst is 44.4 s.

[0099] Figure 23 Example 5 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor based on the modified PdSn catalyst were measured six times under a hydrogen concentration of 500 ppm H2 / air. The specific test procedure was as follows: the sensor was kept in an air atmosphere (blank area in the figure) for 2 minutes, then switched to a 500 ppm H2 / air atmosphere (gray area) for 4 minutes, then switched back to an air atmosphere for 2 minutes… This cycle was repeated six times to complete the test. The results showed that the response current of the sensor was basically consistent throughout the six tests, indicating that the sensor has good repeatability.

[0100] Figure 24 Example 5 shows the preparation of nano-SnO-based materials. x The hydrogen sensor based on the modified PdSn catalyst exhibits CO poisoning resistance under (50 ppm CO + 1000 ppm H2) / air conditions. After being exposed to this atmosphere for approximately 6 minutes, the sensor's response current decreased to 87.6%, a decrease of only 12.4%. This indicates that the performance of the PdSn-based hydrogen sensor is based on nano-SnO. x The hydrogen sensor based on the modified PdSn catalyst exhibits good resistance to CO poisoning.

[0101] Example 6 2 mmol ascorbic acid, 0.5 mmol tin tetrachloride, and 0.5 mmol potassium chloride palladiumate were uniformly dispersed in 10 ml of ethanol. The mixture was then reacted at 120 °C and 500 rpm for 8 hours with stirring, followed by cooling to room temperature. The mixture was then centrifuged and washed three times with a 5:1 mixture of ethanol and cyclohexane at 10,000 rpm, followed by three more centrifugations with a 5:1 mixture of ethanol and water. After centrifugal purification, the mixture was dried in a 65 °C oven for 12 hours. The resulting black catalyst powder was nano-SnO. xA modified PdSn catalyst. The catalyst contains 83.3 wt.% Pd and 16.7 wt.% Sn.

[0102] Following the method in Example 1, nano-SnO x The modified PdSn catalyst was used to prepare a hydrogen sensing electrode and a hydrogen sensor.

[0103] Figure 25 Example 6 shows the preparation of nano-SnO-based materials. x X-ray diffraction (XRD) pattern of the modified PdSn catalyst. XRD shows that the diffraction peaks of the catalyst correspond to those of Pd (PDF#87-0643), indicating that the introduction of Sn into the PdSn nanoparticles did not significantly alter the Pd crystal structure, which remains face-centered cubic, and no obvious SnO was observed. x The diffraction peaks suggest that SnO x It exists in a weakly crystalline form.

[0104] Figure 26 Example 6 shows the preparation of nano-SnO-based materials. x The response time analysis of the hydrogen sensor with modified PdSn catalyst at a hydrogen concentration of 500 ppm H2 / air is shown in the figure. As shown, when the test gas of 500 ppm H2 / air is introduced at time (X-axis) 0 s, the relative response current (Y-axis) of the sensor reaches 90% after 33.9 s; this time is the response time. Based on nano-SnO... x The hydrogen sensor response time of the modified PdSn catalyst is 33.9 s.

[0105] Figure 27 Example 6 shows the preparation of nano-SnO-based materials. x The pulse response curves of the hydrogen sensor based on the modified PdSn catalyst were measured six times under a hydrogen concentration of 500 ppm H2 / air. The specific test procedure was as follows: the sensor was kept in an air atmosphere (blank area in the figure) for 2 minutes, then switched to a 500 ppm H2 / air atmosphere (gray area) for 4 minutes, then switched back to an air atmosphere for 2 minutes… This cycle was repeated six times to complete the test. The results showed that the response current of the sensor was basically consistent throughout the six tests, indicating that the sensor has good repeatability.

[0106] Figure 28 Example 6 shows the preparation of nano-SnO-based materials. xThe hydrogen sensor based on the modified PdSn catalyst exhibits CO poisoning resistance under (50 ppm CO + 1000 ppm H2) / air conditions. After being exposed to the (50 ppm CO + 1000 ppm H2) / air atmosphere for approximately 6 minutes, the sensor's response current value decayed to 85.0%, a decrease of only 15.0%. This indicates that the performance of the hydrogen sensor based on nano-SnO is relatively stable. x The hydrogen sensor based on the modified PdSn catalyst exhibits good resistance to CO poisoning.

[0107] Comparative Example 1 mmol of glucose and 0.5 mmol of potassium chloride palladium were uniformly dispersed in 5 ml of oleylamine and 5 ml of octadecene. The mixture was reacted at 180 °C and 500 rpm for 6 h, and then cooled to room temperature. The mixture was then centrifuged and washed three times with a 5:1 mixture of ethanol and cyclohexane at 10,000 rpm, and then centrifuged and washed three times with a 5:1 mixture of ethanol and water. After centrifugation purification, the mixture was dried in a 65 °C oven for 12 h. The resulting black catalyst powder was the Pd black catalyst.

[0108] Following the method in Example 1, the Pd black catalyst was prepared into a hydrogen sensing electrode and a hydrogen sensor.

[0109] Figure 29 The X-ray diffraction (XRD) spectra of the Pd black catalyst prepared in a comparative manner are shown. The XRD shows that the diffraction peaks of the catalyst correspond to the diffraction peaks of Pd (PDF#87-0643), indicating the successful preparation of the face-centered cubic Pd black catalyst.

[0110] Figure 30 This is a graph showing the response time analysis of a Pd black catalyst-based hydrogen sensor prepared in a comparative manner at a hydrogen concentration of 500 ppm H2 / air. As shown in the figure, when the test gas of 500 ppm H2 / air is introduced at time (X-axis) 0 s, the relative response current (Y-axis) of the sensor reaches 90% after 103.3 s; this time is the response time. The response time of the Pd black catalyst-based hydrogen sensor is 103.3 s.

[0111] Figure 31 This is a graph showing the CO poisoning resistance of a Pd black catalyst-based hydrogen sensor prepared in a comparative manner under (50 ppm CO + 1000 ppm H2) / air conditions. After being kept in the (50 ppm CO + 1000 ppm H2) / air atmosphere for approximately 6 minutes, the sensor's response current value decreased to 83.3%, a decrease of 16.7%. This indicates that the Pd black catalyst-based hydrogen sensor has insufficient CO poisoning resistance.

Claims

1. A nano-SnO x A method for preparing modified PdSn catalysts, characterized in that, Includes the following steps: Palladium salt, tin salt, and reducing agent were dispersed in an organic solvent and reacted for a certain time under specific temperature and stirring conditions. After centrifugation and washing with a cleaning agent and drying, nano-SnO was obtained. x Modified PdSn catalyst.

2. The preparation method according to claim 1, characterized in that, The concentration of the palladium salt in the organic solvent is 10-500 mmol / L; The concentration of the tin salt in the organic solvent is 5-300 mmol / L; The concentration of the reducing agent in the organic solvent is 30-1500 mmol / L.

3. The preparation method according to claim 1, characterized in that, The palladium salt mentioned is one of palladium acetylacetonate, potassium chloride palladium, palladium chloride, sodium chloride palladium, palladium acetate, dichlorotetramine palladium, palladium nitrate, and palladium sulfate. The tin salt mentioned is one of tin acetylacetonate, tin acetate, tin sulfate, tin tetrachloride, and tin oxalate; The reducing agent is one of glucose, maltose, ribose, methanol, formaldehyde, formic acid, benzyl alcohol, ascorbic acid, sodium borohydride, polyol, oxalic acid, and molybdenum hexacarbonyl. The organic solvent is one or more of oleylamine, octadecene, methanol, ethanol, ethylene glycol, propanol, butanol, pentanol, oleic acid, and dodecylamine.

4. The preparation method according to claim 1, characterized in that, The reaction temperature is 80-250℃, the stirring speed is 100-900rpm, and the reaction time is 0.5-24h.

5. The preparation method according to claim 1, characterized in that, The cleaning agent is a mixture of ethanol and cyclohexane, and a mixture of ethanol and water. The centrifugal washing method is as follows: centrifuge and wash 3-5 times with the mixture of ethanol and cyclohexane at 8000-11000 rpm, and then centrifuge and wash 3-5 times with the mixture of ethanol and water. The volume ratio of ethanol to cyclohexane in the ethanol and cyclohexane mixture is 10-2:1, and the volume ratio of ethanol to water in the ethanol and water mixture is 10-2:

1. Each centrifugation time is 3-10 min. The drying temperature is -50-90℃, and the drying time is 1-72h.

6. Nano-SnO prepared by the preparation method according to any one of claims 1-5 x Modified PdSn catalyst.

7. A nano-SnO based on the method described in claim 6 x A method for preparing a hydrogen sensing electrode based on a modified PdSn catalyst, characterized in that, Includes the following steps: Nano SnO x The modified PdSn catalyst was mixed uniformly with water, ethanol, and ionomer in a certain proportion to prepare a catalyst slurry. The slurry was then sprayed onto the surface of a perfluorosulfonic acid resin membrane to obtain a catalyst layer, which is based on nano-SnO. x Hydrogen sensing electrode with modified PdSn catalyst.

8. The preparation method according to claim 7, characterized in that, The ionomer is a perfluorosulfonic acid resin; when used, the ionomer is an ionomer solution, and the volume ratio of water, anhydrous ethanol, and the ionomer solution is 1:9:(0-0.5); the concentration of the catalyst in the catalyst slurry is 0.1-2 mg / cm³. 2 ; The coating conditions are as follows: the catalyst slurry is sprayed onto the perfluorosulfonic acid resin film on a vacuum heating platform at 60-85°C to obtain a catalyst layer, which is the hydrogen sensing electrode. The catalyst loading in the hydrogen sensing electrode is 0.01-2 mg / cm³. 2 .

9. The nano-SnO prepared by the preparation method according to claim 7 or 8 x Hydrogen sensing electrode with modified PdSn catalyst.

10. The nano-SnO according to claim 6 x Application of modified PdSn catalyst or hydrogen sensing electrode as described in claim 9 in electrochemical hydrogen sensing.

Images