A palladium-based hydride and its preparation method and application

Abstract

The present invention belongs to the technical field of preparation of metal hydrides, and specifically relates to a palladium-based hydride and a preparation method and application thereof. The present invention generates hydrogen through a cross-coupling reaction between a hydrogenating agent, iminonitrile, and a phenyl alcohol organic solvent. This combined hydrogenation mechanism not only ensures a high exposure density of active metal palladium sites, but also a high hydrogen content can effectively induce crystal expansion of Pd crystals, and enhance the electronic interaction between neighboring atoms, optimize the crystal structure and electronic configuration of the palladium-based hydride catalyst, and is conducive to improving the activity and stability of the palladium-based hydride catalyst, greatly improving its specific activity, effectively reducing the use of metal palladium, and effectively reducing the use cost. It exhibits relatively excellent electrocatalytic activity for EOR under alkaline conditions and has considerable energy application potential.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of metal hydrides, and specifically relates to a palladium-based hydride and a preparation method and application thereof. Background Art

[0002] As environmental pollution and energy crisis become increasingly serious, fuel cell technology has great development prospects due to its significant advantages such as high energy efficiency, low environmental pollution, and wide fuel range. Among them, direct ethanol fuel cells (DAFCs) have attracted widespread attention due to their advantages such as high portability and high energy density. At present, the most effective (EOR) electrocatalyst is still the precious metal platinum. However, the disadvantages of low natural abundance and high cost of precious metal platinum directly restrict the large-scale commercial development of direct ethanol fuel cells. Therefore, the development of alternative, highly active non-platinum-based EOR electrocatalysts is the key to achieving the market application of cost-effective direct ethanol fuel cells.

[0003] Palladium has an electronic structure and chemical properties similar to those of platinum and is considered a potential alternative metal. Palladium hydride has electrocatalytic performance and stability comparable to platinum due to its significant electronic and structural effects, and has therefore received increasing research attention in the field of electrocatalysis. On the one hand, due to the smallest atomic size of hydrogen atoms, their effective doping will cause the palladium lattice to expand, thereby effectively weakening the adsorption strength of oxygen-containing species; on the other hand, due to the difference in electronegativity, significant electron transfer and s, pd orbital hybridization will occur between the doped hydrogen atoms and adjacent palladium atoms, which can effectively change the electronic configuration of palladium atoms and the surface adsorption properties, thereby significantly enhancing the electrocatalytic performance of traditional palladium-based catalysts.

[0004] Traditional palladium hydride catalysts usually use organic molecules (such as formaldehyde, sodium borohydride, DMF, n-butylamine, etc.) as hydrogen sources and are synthesized by wet chemical methods. These organic molecules can release hydrogen and adsorb on the palladium surface under the catalytic degradation of palladium materials, and then dissociate on the palladium surface to produce hydrogen atoms. These atoms can penetrate into the palladium lattice and finally occupy the interstitial position to form PdH x It is worth mentioning that PdH obtained by heat treatment with DMF or n-butylamine as hydrogen source x The maximum value of x is usually limited to 0.43, which can only achieve a lower degree of performance improvement compared to Pd, and it is difficult to achieve a hydrogen doping level above 0.7. Therefore, it is necessary to explore effective hydrogenating agents to effectively synthesize high-performance palladium hydride PdH with a high hydrogen content. 0.706 The simple and large-scale preparation of Summary of the invention

[0005] In view of this, the object of the present invention is to provide a palladium-based hydride and a preparation method and application thereof, wherein the method can effectively prepare a palladium-based hydride with high hydrogen content and high electrocatalytic activity.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a palladium-based hydride, comprising the following steps:

[0008] The metal salt, the iminonitrile and the phenyl alcohol organic solvent are mixed and subjected to a solvothermal reaction to obtain a palladium-based hydride;

[0009] The metal salt includes a palladium salt.

[0010] Preferably, the metal salt also includes other metal salts, and the other metal salts include one or more of platinum acetylacetonate, ruthenium acetylacetonate, nickel acetylacetonate, iron acetylacetonate, cobalt acetylacetonate, molybdenum acetylacetonate, copper acetylacetonate and tungsten acetylacetonate.

[0011] Preferably, the palladium salt includes one or more of palladium acetylacetonate, palladium chloride, potassium chloropalladate and palladium acetate.

[0012] Preferably, the iminonitrile is iminodiacetonitrile and / or iminodiapropionitrile.

[0013] Preferably, the phenyl alcohol organic solvent preferably includes one or more of benzyl alcohol, phenylethyl alcohol, phenylpropanol, phenylbutanol and phenylpentanol.

[0014] Preferably, the mass ratio of the iminonitrile to the metal salt is (0.01-1000):1.

[0015] Preferably, the mass ratio of the palladium salt to the other metal salt is 1:(0.01-100).

[0016] Preferably, the ratio of the mass of the iminonitrile to the volume of the phenyl alcohol organic solvent is (0.01-200) mg:(1-100) mL.

[0017] The present invention also provides a palladium-based hydride prepared by the preparation method described in the above technical solution, wherein the atomic ratio of palladium to hydrogen in the palladium-based hydride is 1:0.706.

[0018] The present invention also provides the use of the palladium-based hydride described in the above technical solution in electrocatalysis.

[0019] The invention provides a method for preparing a palladium-based hydride, comprising the following steps: mixing a metal salt, an iminonitrile and a phenyl alcohol organic solvent, and performing a solvent thermal reaction to obtain a palladium-based hydride; the metal salt comprises a palladium salt.

[0020] The present invention generates hydrogen through a cross-coupling reaction between the hydrogenating agent iminonitrile and the benzyl alcohol organic solvent, and the adsorbed hydrogen dissociates into hydrogen atoms and penetrates into the subsurface region of the palladium crystal, and finally occupies its interstitial position to form a palladium-based hydride. This iminonitrile and benzyl alcohol organic solvent combined hydrogenation mechanism not only ensures a high exposure density of active metal palladium sites, but also a high hydrogen content can effectively induce crystal expansion of the Pd crystal, and enhance the electronic interaction between neighboring atoms, optimize the crystal structure and electronic configuration of the palladium-based hydride catalyst, which is beneficial to improve the activity and stability of the palladium-based hydride catalyst, greatly improve its specific activity, effectively reduce the use of metal palladium, and effectively reduce the use cost. It exhibits relatively excellent electrocatalytic activity for EOR under alkaline conditions and has considerable energy application potential. The present invention prepares a palladium-based hydride PdH with a high hydrogen content by a one-step solvent method. 0.706 In the preparation of quartz crystals, the higher the hydrogen content, the more beneficial it is to the improvement of specific activity.

[0021] Furthermore, the method provided by the present invention has good universality and can be extended to the effective preparation of a series of palladium-based hydride (PdMH, M = Cu, Ni, Co, Fe, Mo, W, Pt, Ru) nanoparticles. Compared with palladium hydride, the introduction of another metal, PdMH alloy hydride has a larger Pd-Pd / M bond length, lower electron density and metal coordination number. These advantages play an important role in modifying the intrinsic activity of active sites, which is conducive to further regulation of Pd electronic structure, and further promotes its electrocatalytic activity. Compared with unhydrogenated Pd-based nanoparticles, it exhibits excellent electrocatalytic activity for alkaline ethanol fuel cell anode oxidation reaction. The preparation process and equipment of the present invention are simple, and it is easy to achieve large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The palladium hydride (PdH 0.706 ) High-resolution transmission electron microscopy (HRTEM) images of nanoparticles and Pd nanoparticles;

[0023] Figure 2 The palladium hydride (PdH 0.706 ) Valence band X-ray diffraction photoelectron spectroscopy (VB-XPS) of nanoparticles;

[0024] Figure 3 The XRD spectrum of the product obtained when the benzyl alcohol in Example 1 is replaced by benzaldehyde or benzonitrile as the solvent, or the iminodiacetonitrile is replaced by glutaronitrile, diethylamine, or iminodiacetic acid;

[0025] Figure 4XRD spectra of PdCuH, PdNiH, PdCoH, PdFeH, PdMoH, PdWH, PdPtH and PdRuH prepared by the present invention;

[0026] Figure 5 The PdH prepared in the present invention 0.706 Ethanol electrocatalytic oxidation curves of nanoparticles, Pd nanoparticles, and commercial Pd black. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing a palladium-based hydride, comprising the following steps:

[0028] The metal salt, the iminonitrile and the phenyl alcohol organic solvent are mixed and subjected to a solvothermal reaction to obtain a palladium-based hydride;

[0029] The metal salt includes a palladium salt.

[0030] Unless otherwise specified, the present invention has no special requirements on the sources of the raw materials used in the preparation, and commercially available products known to those skilled in the art can be used.

[0031] The invention mixes metal salt, iminonitrile and phenyl alcohol organic solvent to obtain a mixture.

[0032] In the present invention, the metal salt includes a palladium salt; the palladium salt preferably includes one or more of palladium acetylacetonate, palladium chloride, potassium chloropalladate and palladium acetate, and more preferably palladium acetylacetonate. When the palladium salt is the above-mentioned types, the present invention has no special restrictions on the ratio of different types of palladium salts, and any ratio can be used.

[0033] In the present invention, the metal salt also includes other metal salts, and the other metal salts preferably include one or more of acetylacetonate platinum, acetylacetonate ruthenium, acetylacetonate nickel, acetylacetonate iron, acetylacetonate cobalt, acetylacetonate molybdenum, acetylacetonate copper and acetylacetonate tungsten, and more preferably acetylacetonate platinum, acetylacetonate ruthenium, acetylacetonate nickel, acetylacetonate iron, acetylacetonate cobalt, acetylacetonate molybdenum, acetylacetonate copper or acetylacetonate tungsten. When the other metal salts are the above-mentioned ones, the present invention has no special restrictions on the ratio of different types of other metal salts, and any ratio can be used.

[0034] In the present invention, the iminonitrile is preferably iminodiacetonitrile and / or iminodiapropionitrile, more preferably iminodiacetonitrile or iminodiapropionitrile. When the iminonitrile is iminodiacetonitrile and iminodiapropionitrile, the present invention has no particular limitation on the ratio of iminodiacetonitrile and iminodiapropionitrile, and any ratio can be used.

[0035] In the present invention, the phenyl alcohol organic solvent preferably includes one or more of benzyl alcohol, phenylethyl alcohol, phenylpropyl alcohol, phenylbutyl alcohol and phenylpentyl alcohol, more preferably benzyl alcohol, phenylethyl alcohol or phenylpropyl alcohol. When the phenyl alcohol organic solvent is the above-mentioned several kinds, the present invention has no special limitation on the ratio of different kinds of phenyl alcohol organic solvents, and any ratio can be used.

[0036] In the present invention, the mass ratio of the iminonitrile to the metal salt is preferably (0.01-1000):1, more preferably (0.1-10):1, and most preferably 6.67:1.

[0037] In the present invention, the mass ratio of the palladium salt to the other metal salt is preferably 1:(0.01-100), more preferably 1:(0.1-10), and most preferably 1:1.

[0038] In the present invention, the ratio of the mass of the iminonitrile to the volume of the phenyl alcohol organic solvent is preferably (0.01-200) mg:(1-100) mL, more preferably (1-200) mg:(10-50) mL, and most preferably 200 mg:30 mL.

[0039] In the present invention, the mixing is preferably adding the metal salt and the iminonitrile to a phenyl alcohol organic solvent and performing ultrasound; the temperature of the ultrasound is preferably 5 to 80°C, more preferably 25 to 30°C, and most preferably 25°C; the power of the ultrasound is preferably 50 to 2000W, more preferably 100 to 500W, and most preferably 180W; the time of the ultrasound is preferably 5 to 120min, more preferably 10 to 30min, and most preferably 15min.

[0040] After obtaining the mixed material, the present invention performs a solvent thermal reaction on the mixed material.

[0041] In the present invention, the temperature of the solvothermal reaction is preferably 80-300°C, more preferably 100-200°C, most preferably 140°C; the time of the solvothermal reaction is preferably 0.1-72h, more preferably 1-10h, most preferably 1h.

[0042] The invention uses a CN bond cross-coupling reaction between a phenyl alcohol organic solvent and an iminonitrile, each of which releases corresponding hydrogen atoms to form hydrogen gas. During the solvent thermal reaction, palladium salt and other metal salts are reduced at the same time to generate elemental palladium and other metal atoms, and further form an alloy. The generated hydrogen gas is adsorbed on the surface of palladium, dissociated into hydrogen atoms, and penetrated into the subsurface area of ​​the palladium crystal, and finally occupies the interstitial position thereof to form a palladium-based hydride.

[0043] The present invention uses a one-step solvothermal method to synthesize palladium-based hydrides using cross-coupling hydrogen production between phenyl alcohol organic solvents and imino nitrile as a hydrogen source. The hydrogenation method is unique and universal. In addition, the present invention avoids the loss of palladium materials and achieves a high hydrogen loading of x=0.706, and the specific activity of the obtained palladium-based hydride is also effectively enhanced. In other words, the combined hydrogenation mechanism of phenyl alcohol organic solvents and imino nitrile not only ensures a higher exposure density of active metal palladium sites and the structural stability of the catalyst, but also the higher hydrogen loading enhances the electronic interaction between neighboring atoms. These factors have a positive impact on improving the electrocatalytic performance.

[0044] After the solvent thermal reaction, the present invention preferably further comprises: separating the solid-liquid product obtained from the solvent thermal reaction, and washing and drying the obtained solid in sequence to obtain a palladium-based hydride.

[0045] In the present invention, the solid-liquid separation method is preferably centrifugation; the centrifugal speed is preferably 6000-12000rpm, more preferably 7000-10000rpm, most preferably 9000rpm; the centrifugal time is preferably 1-10min, more preferably 1-5min, most preferably 5min.

[0046] In the present invention, the number of washing is preferably 1 to 10 times, more preferably 3 to 6 times, and most preferably 6 times; the reagent used for washing is preferably ethanol; the washing is preferably carried out under ultrasonic conditions; the temperature of the ultrasound is preferably 5 to 80°C, more preferably 20 to 50°C, and most preferably 25°C; the power of the ultrasound is preferably 50 to 2000W, more preferably 100 to 500W, and most preferably 180W; the time of the ultrasound is preferably 5 to 120min, more preferably 10 to 30min, and most preferably 15min.

[0047] In the present invention, the drying is preferably vacuum drying; the equipment for vacuum drying is preferably a DZF type vacuum drying oven; the drying temperature is preferably 10 to 50°C, more preferably 20 to 30°C, and most preferably 25°C; the drying time is preferably 0.5 to 24h, more preferably 5 to 10h, and most preferably 6h; the vacuum degree of the vacuum drying is preferably -0.2 to 0.1MPa, more preferably -0.1 to 0.1MPa, and most preferably -0.1MPa.

[0048] The higher hydrogen content in the palladium-based hydride prepared by the present invention effectively induces crystal expansion of palladium crystals and enhances the electronic interaction between adjacent atoms, optimizes the crystal structure and electronic configuration of the catalyst, and is beneficial to improving the electrocatalytic performance of the palladium-based hydride.

[0049] The present invention also provides a palladium-based hydride prepared by the preparation method described in the above technical solution, wherein the atomic ratio of palladium to hydrogen in the palladium-based hydride is 1:0.706.

[0050] The present invention also provides the use of the palladium-based hydride described in the above technical solution in electrocatalysis.

[0051] The present invention has no special limitation on the application of the palladium-based hydride in electrocatalysis, and any application method known in the art may be used.

[0052] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0053] Example 1

[0054] 30 mg of acetylacetonate palladium and 200 mg of iminodiacetonitrile were weighed and added to 30 mL of benzyl alcohol solvent. The obtained mixed solution was fully ultrasonicated at 25° C. and 180 W power for 15 min. After mixing evenly, the obtained mixed solution was placed in a reactor, heated to 140° C. and maintained for 1 h for solvent thermal reaction. After the reaction was completed, the obtained solution was centrifuged at 9000 rpm for 5 min, the supernatant was removed, and an appropriate amount of ethanol was added. Then, the solution was fully ultrasonicated at 25° C. and 180 W power for 15 min. After ultrasonication was uniform, the obtained uniform solution was centrifuged again, and the solution was repeatedly washed with ethanol for 6 times until the final centrifugal supernatant was completely clear and transparent. The obtained black product was placed at 25° C. and dried in a DZF vacuum drying oven at a vacuum degree of -0.1 MPa for 6 h to obtain palladium hydride (PdH 0.706 ) nanoparticles;

[0055] According to the comparison of the standard card, the product obtained by the present invention is consistent with PdH 0.706 The standard card (PDF#18-0951) completely overlaps, so the relative content x of hydrogen is 0.706.

[0056] Example 2

[0057] The difference from Example 1 is that palladium acetylacetonate is replaced by palladium chloride, and the rest of the contents are consistent with Example 1.

[0058] Example 3

[0059] The difference from Example 1 is that palladium acetylacetonate is replaced by potassium chloropalladate, and the rest of the content is consistent with Example 1.

[0060] Example 4

[0061] The difference from Example 1 is that palladium acetylacetonate is replaced by palladium acetate, and the rest of the contents are consistent with Example 1.

[0062] Example 5

[0063] The difference from Example 1 is that benzyl alcohol is replaced by phenylethyl alcohol, and the rest of the content is consistent with Example 1.

[0064] Example 6

[0065] The difference from Example 1 is that benzyl alcohol is replaced by phenylpropanol, and the rest of the content is consistent with Example 1.

[0066] Example 7

[0067] The difference from Example 1 is that benzyl alcohol is replaced by phenylbutanol, and the rest of the content is consistent with Example 1.

[0068] Example 8

[0069] The difference from Example 1 is that benzyl alcohol is replaced by phenylpentanol, and the rest of the content is consistent with Example 1.

[0070] Example 9

[0071] The difference from Example 1 is that iminodiacetonitrile is replaced by iminodiapropionitrile, and the rest of the content is consistent with Example 1.

[0072] Example 10

[0073] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 0.2 mg of palladium acetylacetonate, and the rest of the content is consistent with Example 1.

[0074] Embodiment 11

[0075] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 20 g of palladium acetylacetonate, and the rest of the content is consistent with Example 1.

[0076] Example 12

[0077] The difference from Example 1 is that 200 mg of iminodiacetonitrile is replaced by 0.01 mg of iminodiacetonitrile, and 30 mL of benzyl alcohol is replaced by 100 mL of benzyl alcohol. The rest of the content is consistent with Example 1.

[0078] Embodiment 13

[0079] The difference from Example 1 is that 30 mL of benzyl alcohol is replaced by 1 mL of benzyl alcohol, and the rest of the content is consistent with Example 1.

[0080] Embodiment 14

[0081] The difference from Example 1 is that the temperature of the solvent thermal reaction is replaced from 140° C. to 80° C., and the rest of the contents are consistent with Example 1.

[0082] Embodiment 15

[0083] The difference from Example 1 is that the temperature of the solvent thermal reaction is replaced from 140° C. to 300° C., and the rest of the contents are consistent with Example 1.

[0084] Example 16

[0085] The difference from Example 1 is that the time of the solvent thermal reaction is replaced from 1 h to 0.1 h, and the rest of the contents are consistent with Example 1.

[0086] Embodiment 17

[0087] The difference from Example 1 is that the time of the solvent thermal reaction is replaced from 1 h to 72 h, and the rest of the contents are consistent with Example 1.

[0088] Embodiment 18

[0089] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 15 mg of palladium acetylacetonate and 15 mg of platinum acetylacetonate, and the rest of the content is consistent with Example 1.

[0090] Embodiment 19

[0091] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 15 mg of palladium acetylacetonate and 0.15 mg of platinum acetylacetonate, and the rest of the content is consistent with Example 1.

[0092] Embodiment 20

[0093] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 15 mg of palladium acetylacetonate and 1.5 g of platinum acetylacetonate, and the rest of the content is consistent with Example 1.

[0094] Embodiment 21

[0095] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 15 mg of palladium acetylacetonate and 15 mg of ruthenium acetylacetonate, and the rest of the content is consistent with Example 1.

[0096] Embodiment 22

[0097] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 15 mg of palladium acetylacetonate and 15 mg of nickel acetylacetonate, and the rest of the content is consistent with Example 1.

[0098] Embodiment 23

[0099] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 15 mg of palladium acetylacetonate and 15 mg of ferric acetylacetonate, and the rest of the content is consistent with Example 1.

[0100] Embodiment 24

[0101] The difference from Example 1 is that 30 mg of acetylacetonate palladium is replaced by 15 mg of acetylacetonate palladium and 15 mg of acetylacetonate cobalt, and the rest of the content is consistent with Example 1.

[0102] Embodiment 25

[0103] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 15 mg of palladium acetylacetonate and 15 mg of platinum acetylacetonate, and the rest of the content is consistent with Example 1.

[0104] Embodiment 26

[0105] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 15 mg of palladium acetylacetonate and 15 mg of copper acetylacetonate, and the rest of the content is consistent with Example 1.

[0106] Embodiment 27

[0107] The difference from Example 1 is that 30 mg of palladium acetylacetonate is replaced by 15 mg of palladium acetylacetonate and 15 mg of tungsten acetylacetonate, and the rest of the contents are consistent with Example 1.

[0108] Comparative Example 1

[0109] The preparation method of palladium-based hydride in the existing public literature (Sun, H.-Y.; Ding, Y.; Yue, Y.-Q.; Xue, Q.; Li, F.-M.; Jiang, J.-X.; Chen, P.; Chen, Y., Bifunctional Palladium Hydride Nanodendrite Electrocatalysts for Hydrogen Evolution Integrated with Formate Oxidation. ACS Appl. Mater. Interfaces 2021, 13, 13149. DOI: 10.1021 / acsami.0c22106) comprises the following steps:

[0110] 38.5 mg of acetylacetonate palladium, 0.1 g of 2-methylimidazole, 250 mg of polyvinylpyrrolidone (PVP) and 1 g of ascorbic acid were weighed and dissolved in 60 mL of dimethylformamide (DMF) and stirred vigorously. The resulting uniform solution was placed in a reactor and hydrothermally reacted at 160°C for 5 h. The resulting product was centrifuged at 9000 rpm for 3 min, then washed 3 times with equal proportions of ethanol and water and dried at room temperature to obtain palladium nanodendrites.

[0111] More than 10 mg of palladium nanodendrites were weighed and dissolved in 20 mL of dimethylformamide (DMF), and hydrothermally reacted at 160° C. for 5 h. The resulting product was centrifuged at 9000 rpm for 3 min, then washed with ethanol and water three times and dried at room temperature to obtain PdH0.5 nanodendrites.

[0112] Comparative Example 2

[0113] The preparation method of palladium-based hydride in the existing public literature (Fan, J.; Cui, X.; Yu, S.; Gu, L.; Zhang, Q.; Meng, F.; Peng, Z.; Ma, L.; Ma, JY; Qi, K.; Bao, Q.; Zheng, W., Interstitial Hydrogen Atom Modulation to Boost Hydrogen Evolution in Pd-Based Alloy Nanoparticles. ACS Nano 2019, 13, 12987. DOI: 10.1021 / acsnano.9b05615) comprises the following steps:

[0114] 8 mg of palladium acetylacetonate, 8 mg of ruthenium acetylacetonate and 120 mg of polyvinyl pyrrolidone (PVP) were weighed and added to a mixed solution containing 3 mL of benzyl alcohol and 3 mL of acetaldehyde and stirred vigorously for 1 hour. The resulting uniform solution was placed in a reactor and hydrothermally reacted at 180°C for 8 hours. The resulting product was centrifuged at 12000 rpm for 10 minutes, then washed three times with equal proportions of ethanol and cyclohexane solution and dried at room temperature to obtain PdRuH0.4 nanodendrites.

[0115] Comparative Example 3

[0116] The preparation method of palladium-based hydride in the existing public literature (Wu, J.; Cui, X.; Fan, J.; Zhao, J.; Zhang, Q.; Jia, G.; Wu, Q.; Zhang, D.; Hou, C.; Xu, S.; Jiao, D.; Gu, L.; Singh, DJ; Zheng, W., Stable Bimetallene Hydride Boosts Anodic CO Tolerance of Fuel Cells. ACS Energy Letters 2021, 6, 1912. DOI: 10.1021 / acsenergylett.1c00614) comprises the following steps:

[0117] 8 mg of acetylacetonate palladium, 0.5 mg of acetylacetone, and 50 mg of ascorbic acid were weighed and dissolved in 5 mL of oleylamine and stirred at room temperature for 20 min. The resulting uniform solution was maintained at 180°C in an oil bath for 2 h. After cooling to room temperature, the resulting black product was centrifuged and washed several times with cyclohexane, and dried at room temperature to obtain PdMoH0.33 nanoparticles.

[0118] Performance Testing

[0119] (1) High-resolution transmission electron microscopy (HRTEM) was used to examine the palladium hydride (PdH 0.706 ) nanoparticles and Pd nanoparticles were physically characterized. Figure 1 shown.

[0120] Depend on Figure 1 It can be seen that the palladium hydride (PdH 0.706 ) nanoparticles have uniform morphology and smaller particle size than Pd nanoparticles, which can provide abundant active sites. The calculated PdH 0.706 The electrochemically active area (ECSA) of the nanoparticles is 38.08 m 2 / g, significantly higher than commercial Pd black (17.16m 2 / g) and unhydrogenated Pd nanoparticles (18.53 m 2 / g). In addition, it can be seen that PdH 0.706 The significantly increased lattice fringe spacing indicates that the effective doping of hydrogen atoms causes the palladium lattice to expand.

[0121] (2) The palladium hydride (PdH) prepared in Example 1 0.706 ) nanoparticles were subjected to valence band X-ray diffraction photoelectron spectroscopy (VB-XPS) analysis, and the results are as follows Figure 2 shown.

[0122] Depend on Figure 2 It can be seen that the hydrogenated PdH 0.706 The nanoparticles have a narrow valence band, indicating that PdH 0.706 The bond length of Pd-Pd bonds in the nanoparticles was effectively increased, demonstrating the efficient formation of hydrides.

[0123] (3) In the present invention, the XRD spectrum of the product is obtained when the benzyl alcohol in Example 1 is replaced by benzaldehyde or benzonitrile as the solvent, or the iminodiacetonitrile is replaced by glutaronitrile, diethylamine, or iminodiacetic acid. The results are as follows: Figure 3 shown.

[0124] Depend on Figure 3 It can be seen that PdH 0.706 The diffraction peak position of nanoparticles is related to PdH 0.706The standard card (PDF#18-0951) completely overlaps and has a significant left shift relative to the Pd standard card, proving that the combined hydrogenation of iminodiacetonitrile and benzyl alcohol can produce PdH with a high H content. 0.706 Furthermore, to verify the combined hydrogenation mechanism of iminodiacetonitrile and benzyl alcohol, the benzyl alcohol was replaced with benzonitrile or benzaldehyde, or iminodiacetonitrile was replaced with iminodiacetic acid or glutaronitrile or diethylamine. It was found that the PdH 0.706 Nanoparticles, PdH can only be successfully prepared under the combined action of iminodiacetonitrile and benzyl alcohol 0.706 Nanoparticles. It can be seen that the hydrogen source of the system may be generated according to the following equation, that is, hydrogen is generated through a cross-coupling reaction between iminodiacetonitrile and benzyl alcohol:

[0125]

[0126] (4) XRD analysis of PdCuH, PdNiH, PdCoH, PdFeH, PdMoH, PdWH, PdPtH, and PdRuH prepared by the present invention showed the following results: Figure 4 The contents of Pd and other metal elements are shown in Table 1.

[0127] Table 1 Content of metal elements in palladium-based hydrides

[0128] PdM Pd(at.%) M(at.%) PdH 100 0 PcqI 98.1 1.9 HkDJ 96 4 PcqI 68.4 31.6 Pd 84.9 15.1 PdFeH 90.2 9.8 PdC 87.2 12.7 HkDJ 88.2 11.8 PdC 83.1 16.9

[0129] Depend on Figure 4 It can be seen that the PdH prepared by the method of the present invention 0.706 Nanoparticles can be formed into various PdMH such as PdCuH, PdNiH, PdCoH, PdFeH, PdMoH, PdWH, PdPtH, PdRuH by introducing additional metal salts. 0.706 Nanoparticles.

[0130] As can be seen from Table 1, other metal elements are effectively doped in the palladium-based hydride. In addition, the content of metal palladium in the palladium-based hydride obtained by the method of the present invention is much greater than that of other metals, which means that in the process of preparing the palladium-based hydride by the method of the present invention, the reduction of the palladium metal precursor is better than the reduction of other metals, ensuring a higher exposure density of palladium at the active site.

[0131] (5) Commercial Pd black was selected as a reference catalyst, and the palladium-based hydride (PdH) prepared in Comparative Example 1 was tested by cyclic voltammetry in the voltage range of -1 to 0.4 V (vs. SCE). 0.706 ) nanoparticles, Pd nanoparticles and commercial Pd black for ethanol oxidation. Figure 5 shown.

[0132] like Figure 5 As shown in the figure, in 1.0M KOH+1.0M C2H5OH solution, at 25℃, the three catalysts were tested for ethanol oxidation. It can be seen that PdH 0.706 The mass specific activity of the nanoparticles was 1.53 A / mg, which was 1.39 times that of Pd nanoparticles (1.10 A / mg) and 1.76 times that of commercial Pd black (0.87 A / mg), indicating that PdH 0.706 The ethanol oxidation activity of the nanoparticles was significantly better than that of the other two catalysts.

[0133] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a palladium-based hydride, characterized in that: The following steps are involved: The metal salt, the iminonitrile and the phenyl alcohol organic solvent are mixed and subjected to a solvothermal reaction to obtain a palladium-based hydride; The metal salt includes a palladium salt; The metal salt also includes other metal salts, and the other metal salts include one or more of platinum acetylacetonate, ruthenium acetylacetonate, nickel acetylacetonate, iron acetylacetonate, cobalt acetylacetonate, molybdenum acetylacetonate, copper acetylacetonate and tungsten acetylacetonate; The mass ratio of the iminonitrile to the metal salt is (6.67-10):1; The mass ratio of the palladium salt to the other metal salt is 1:(0.1~10); The ratio of the mass of the iminonitrile to the volume of the phenyl alcohol organic solvent is 200 mg: (1-100) mL.

2. The preparation method according to claim 1, characterized in that: The palladium salt includes one or more of palladium acetylacetonate, palladium chloride, potassium chloropalladate and palladium acetate.

3. The preparation method according to claim 1, characterized in that: The iminonitrile is iminodiacetonitrile and / or iminodiapropionitrile.

4. The preparation method according to claim 1, characterized in that: The phenyl alcohol organic solvent includes one or more of benzyl alcohol, phenylethyl alcohol, phenylpropanol, phenylbutanol and phenylpentanol.

5. The palladium-based hydride prepared by the preparation method according to any one of claims 1 to 4, characterized in that: The atomic ratio of palladium to hydrogen in the palladium-based hydride is 1:0.

706.

6. Use of the palladium-based hydride according to claim 5 in electrocatalysis.

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