A Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, its preparation method and application

Abstract

This invention relates to the field of hydrogen storage materials technology, specifically to a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, its preparation method, and its applications. The Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of this invention consists of a sheet-like NH2-rGO support and Pd-Y(OH)3 nanoclusters; the Pd-Y(OH)3 nanoclusters are supported on the surface of NH2-rGO, and Pd and Y(OH)3 form a heterostructure through strong electron interactions. By introducing a non-noble metal yttrium component and forming a stable composite structure with palladium, this invention improves the activity and selectivity of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst while maintaining high performance and high stability. This overcomes the common problems of low catalytic activity and insufficient hydrogen selectivity in existing formic acid dehydrogenation catalysts, achieving a good balance between catalytic efficiency and material cost.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage materials technology, specifically to a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen (H2), as a clean and renewable energy carrier, is widely regarded as one of the ideal alternatives to traditional fossil fuels. However, the large-scale popularization and application of hydrogen energy still faces two major bottlenecks: low-cost hydrogen production technology and safe and efficient hydrogen storage and transportation technology.

[0003] Against this backdrop, liquid organic hydrogen carrier technology has attracted significant attention due to its safety and ease of storage and transportation. Formic acid, in particular, stands out as a highly promising hydrogen storage medium due to its multiple advantages: it is widely available and can be produced through green pathways such as biomass conversion or carbon dioxide hydrogenation; it has low toxicity, is non-flammable, and highly safe; and it boasts excellent volumetric hydrogen storage density (approximately 53 g H₂ / L). Formic acid releases hydrogen through catalytic decomposition, primarily via two competing pathways: dehydrogenation (producing H₂ and CO₂) and dehydration (producing H₂O and CO). In practical applications, the CO generated by the dehydration side reaction can easily poison and deactivate downstream fuel cell catalysts. Therefore, highly selective catalytic dehydrogenation of formic acid while effectively suppressing CO generation is crucial for improving the practicality of this technology.

[0004] Currently, palladium-based materials are the main active components used for catalytic dehydrogenation of formic acid. Compared with other metals, Pd exhibits superior resistance to CO poisoning and intrinsic catalytic activity. Furthermore, alloy catalysts formed by Pd with precious metals such as gold (Au), silver (Ag), and iridium (Ir) demonstrate significant advantages in activity and selectivity. However, the limited reserves and high costs of precious metals severely restrict their large-scale industrial application. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, its preparation method, and its applications. The Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of this invention is composed of an NH2-rGO support and Pd-Y(OH)3 nanoclusters. The NH2-rGO support is in the form of thin sheets, and the Pd-Y(OH)3 nanoclusters are supported on the surface of NH2-rGO. Pd and Y(OH)3 form a heterostructure through strong electronic interactions. This invention employs an impregnation-co-reduction method, introducing a non-noble metal yttrium component and forming a stable composite structure with palladium. While maintaining high performance and high stability, this significantly improves the activity and selectivity of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, effectively overcoming the problems of low catalytic activity and insufficient hydrogen selectivity (easily producing CO as a byproduct) commonly found in existing formic acid dehydrogenation catalysts. Simultaneously, it achieves a good balance between catalytic efficiency and material cost.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first objective of this invention is to provide a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, which is composed of an NH2-rGO support and Pd-Y(OH)3 nanoclusters; the NH2-rGO support is in the form of a sheet, the Pd-Y(OH)3 nanoclusters are loaded on the surface of the NH2-rGO, and Pd and Y(OH)3 form a heterostructure through strong electronic interactions.

[0007] A second objective of this invention is to provide a method for preparing the above-mentioned Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, comprising the following steps: S1. Mix aminated graphene oxide gel, palladium precursor solution, and yttrium precursor solution to obtain a solution containing Pd. 2+ and Y 3+ The precursor solution.

[0008] S2. Mix NaBH4 with the precursor solution and carry out a reduction reaction. At this time, NaBH4 hydrolyzes to produce OH-. - Pd in ​​the precursor solution 2+ It is reduced to Pd, while Y 3+ In-situ precipitation yields Y(OH)3, resulting in a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst; at this point, Pd and Y(OH)3 are dispersed on aminated graphene oxide in the form of Pd-Y(OH)3 nanoclusters.

[0009] Preferably, the mass ratio of graphene oxide in the aminated graphene oxide gel to palladium in the palladium precursor solution is 1:0.2~2.

[0010] Preferably, in the precursor solution, Pd2+ With Y 3+ The molar ratio is 1:0.2~0.8.

[0011] Preferably, Pd in ​​the palladium precursor solution 2+ The molar ratio of NaBH4 to Pd is 1:10~20. The amount of NaBH4 must be in excess to fully reduce Pd. 2+ However, it should not be too much, otherwise the strong alkalinity of the surrounding environment will destroy the structure of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst; in addition, the metaborate ions generated by the hydrolysis of NaBH4 will be adsorbed on the Pd active center, masking the active site and thus reducing the catalytic performance.

[0012] Preferably, the conditions for the reduction reaction are: stirring at room temperature until no more H2 is produced in the system.

[0013] Preferably, the aminated graphene oxide gel is prepared according to the following steps: A graphene oxide dispersion was mixed with an aminosilane coupling agent and sonicated at room temperature for 30 min, followed by stirring for 30 min to obtain an amino-modified graphene oxide gel, namely NH2-rGO. During the sonic stirring process, the graphene oxide dispersion and the aminosilane coupling agent underwent nucleophilic substitution hydrolysis, covalent grafting, cross-linking, and macroscopic gelation. These interactions worked synergistically, enabling the APTMS-modified GO sheets to be interconnected through chemical bonds and physical interactions, forming a three-dimensional network that runs through the entire system. Water molecules were encapsulated in the pores, resulting in a loss of macroscopic fluidity and the formation of a wet gel.

[0014] In the nucleophilic substitution hydrolysis reaction, the three methoxy groups (-OCH3) of APTMS react sequentially with water to generate three silanol groups (-Si-OH) and methanol. The silanols (-Si-OH) are highly reactive precursors for all subsequent condensation reactions; the reaction formula is as follows: NH2(CH2)3-Si(OCH3)3+3H2O→NH2(CH2)3-Si(OH)3+3CH3OH.

[0015] Covalent grafting (GO functionalization), namely dehydration condensation and nucleophilic substitution, involves the condensation reaction of silanols produced by the hydrolysis of APTMS with hydroxyl or carboxyl groups on the surface of graphene oxide to form covalent Si-OC bonds, permanently anchoring the aminopropyl chain to the GO surface; the reaction formula is as follows: ① Reaction with hydroxyl groups: GO-OH+HO-Si-(CH2)3-NH2→GO-O-Si-(CH2)3-NH2+H2O.

[0016] ② Reaction with carboxyl groups: GO-COOH+HO-Si-(CH2)3-NH2→GO-COO-Si-(CH2)3-NH2+H2O.

[0017] The cross-linking reaction (network formation) is of the type silanol polycondensation reaction. Ungrafted silanol groups react with each other to form Si-O-Si (siloxane) bonds, which are the core chemical bonds for building a three-dimensional network. This allows cross-linking to occur between different APTMS molecules. Bridges are formed between different APTMS chains grafted onto GO, thus "stitching" adjacent GO sheets together. Reaction formula:

[0018] (CH2)3(NH2)-Si(OH)3+(OH)3Si-(CH2)3-NH2→(CH2)3(NH2)-Si(OH)2-O-Si(OH)2-(CH2)3-NH2+H2O (This reaction can continue to form a network polymer).

[0019] The macroscopic process of gelation (physicochemical synergy) is driven by: ① Chemical cross-linking: the above-mentioned Si-O-Si network provides a rigid framework; ② Electrostatic interaction: at the reaction pH, the amino groups at the APTMS ends are protonated to -NH3. + Partially neutralizes the negative charge on the GO surface (-COO). - ), disrupting electrostatic stability and promoting lamellar aggregation; ③ Hydrogen bonding: -NH2 / -NH3 + It forms a hydrogen bond network with -OH, C=O, and -COOH on the GO sheet.

[0020] Preferably, the mass ratio of graphene oxide to aminosilane coupling agent in the graphene oxide dispersion is 1:2~8.

[0021] Preferably, the aminosilane coupling agent is selected from (3-aminopropyl)trimethoxysilane (APTMS) or (3-aminopropyl)triethoxysilane.

[0022] A third objective of this invention is to provide the application of the above-mentioned Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst in the preparation of a catalyst for the catalytic decomposition of formic acid to produce hydrogen.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst composed of an NH2-rGO support and Pd-Y(OH)3 nanoclusters. The NH2-rGO support is in the form of thin sheets, and the Pd-Y(OH)3 nanoclusters are supported on the surface of the NH2-rGO. Pd and Y(OH)3 form a heterostructure through strong electron interactions. The Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of this invention exhibits excellent catalytic activity and durability. This is attributed to the good dispersion of the Pd-Y(OH)3 nanoclusters, the strong electron coupling between Pd and Y(OH)3, the strong electron-metal-support interaction between Pd-Y(OH)3 and NH2-rGO, and the promoting effect of the amino group. When the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of this invention is applied to the catalytic decomposition of formic acid to produce hydrogen, it exhibits excellent catalytic activity at 50°C without additives, with an initial TOF value of 2628.9 / h.

[0024] The main reaction mechanism inferred from isotope experiments is as follows: First, formic acid molecules approach the Pd-Y(OH)3 nanoclusters. The basic amino groups on NH2-rGO act as Brønsted base sites, promoting the breaking of the OH bonds in the formic acid molecules to form Pd-Y(OH)3-[OOCH]. − and [HNH2] + Species; subsequently, electron-rich Pd-Y(OH)3 nanoclusters promote Pd-Y(OH)3-[OOCH] − The CH bond in the species breaks (rate-determining step), thereby generating Pd-Y(OH)3-[H]. − Species; finally, Pd-Y(OH)3-[H] − and [HNH2] + The species undergoes further dehydrogenation, and the exposed Pd active sites then react with other formic acid molecules, continuing the catalytic reaction.

[0025] 2. A method for preparing a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, comprising mixing an aminated graphene oxide gel, a palladium precursor solution, and a yttrium precursor solution to obtain a catalyst containing Pd. 2+ and Y 3+ The precursor solution; NaBH4 is mixed with the precursor solution and a reduction reaction is carried out. At this time, NaBH4 hydrolyzes to produce OH-. - Pd in ​​the precursor solution 2+ It is reduced to Pd nanoparticles, while Y 3+In-situ precipitation yields Y(OH)3, resulting in a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst. This invention employs an impregnation-co-reduction method for one-step synthesis on an amino-functionalized graphene oxide support, simultaneously constructing Pd-Y(OH)3 nanoclusters formed from Pd and Y(OH)3. Due to the electronic interactions between Y(OH)3 and Pd nanoparticles, the electronic structure of the active center can be effectively modulated, lowering the activation barrier of the formic acid dehydrogenation reaction, thereby significantly improving the hydrogen generation rate and selectivity (CO byproducts are suppressed), solving the problems of low activity and insufficient hydrogen selectivity in traditional catalysts. Simultaneously, the amino-functionalized graphene oxide has a good anchoring effect on the Pd-Y(OH)3 nanoclusters, effectively inhibiting the aggregation and loss of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst during the reaction process, significantly enhancing its cycle stability. The Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of the present invention has both excellent catalytic performance and high stability. It optimizes the interaction between the support and the active component by using non-precious metal Y species, which effectively controls the material cost while improving the overall performance and has good prospects for industrial application. Attached Figure Description

[0026] Figure 1 TEM images and particle size distribution diagrams of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1, Pd / NH2-rGO of Comparative Example 1, and Pd-Y(OH)3 / rGO of Comparative Example 3 are shown. Among them, (a), (b), and (c) are TEM images, and (d), (e), and (f) are particle size distribution diagrams. (a) and (d) are from Example 1, (b) and (e) are from Comparative Example 1, and (c) and (f) are from Comparative Example 3.

[0027] Figure 2 The image shows the elemental mapping of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst in Example 1; where (a) is the overlap diagram, (b) represents C element, (c) represents N element, (d) represents O element, (e) represents Y element, and (f) represents Pd element.

[0028] Figure 3The images show the XRD, FTIR, and XPS spectra of different samples. (a) shows the XRD patterns of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1, Pd / NH2-rGO of Comparative Example 1, and Y(OH)3 / NH2-rGO of Comparative Example 2. (b) shows the FTIR spectra of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1, NH2-rGO, and GO. (c) shows the XPS full spectrum of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1, NH2-rGO, and GO. (d) shows the N2-N2 spectrum of the Pd-Y(OH)3 / NH2-rGO of Example 1, Pd / NH2-rGO of Comparative Example 1, Y(OH)3 / NH2-rGO of Comparative Example 2, and NH2-rGO. 1s fine spectra, (e) is the Pd 3d fine spectrum of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1 and the Pd / NH2-rGO of Comparative Example 1, (f) is the Y 3d fine spectrum of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1, the Y(OH)3 / NH2-rGO of Comparative Example 2 and the Pd-Y(OH)3 / rGO of Comparative Example 3.

[0029] Figure 4 The figures show the gas production effects of different samples catalyzing the decomposition of formic acid. (a) shows the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1, Pd / NH2-rGO of Comparative Example 1, Pd-Y(OH)3 / rGO of Comparative Example 3, and Pd-Y(OH)3 of Comparative Example 4; (b) shows the Pd / NH2-rGO of Comparative Example 1 and the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalysts of Examples 1 to 4; (c) shows the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalysts of Examples 1 to 4. Examples 5 to 7 and Comparative Example 5 show the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalysts. (d) shows the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalysts of Examples 1, 8 to 9, and Comparative Example 6, as well as the Pd-Y(OH)3 / rGO of Comparative Example 3. (b) shows the TOF value diagram of formic acid decomposition gas production. (c) shows the TOF value diagram of formic acid decomposition gas production. (d) shows the TOF value diagram of formic acid decomposition gas production.

[0030] Figure 5 The image shows a gas chromatogram of the formic acid decomposition to produce gas catalyzed by the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst in Example 1. In the image, (a) is the result of testing using a TCD detector and (b) is the result of testing using an FID-methane converter.

[0031] Figure 6The figures show the effects of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1 and the Pd / NH2-rGO of Comparative Example 1 on the catalytic decomposition of formic acid to produce gas at 303K~333K. In Example 1, (a) is the inset of (b) and (a) is the inset of (b). The inset in (a) is the Arrhenius diagram and the corresponding activation energy diagram of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1 on the catalytic decomposition of formic acid to produce gas.

[0032] Figure 7 This is a durability test diagram of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst used in Example 1 to catalyze the decomposition of formic acid to produce gas.

[0033] Figure 8 The images show the TEM and particle size distribution of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst after 10 consecutive catalytic decompositions of formic acid to produce gas in Example 1. (a) and (b) are TEM images, and (c) is a particle size distribution image; (a) is 50 nm and (b) is 20 nm. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased on the market or prepared by existing methods.

[0036] While palladium-based catalysts for hydrogen production from formic acid have been extensively studied in the present technology, they still suffer from the following problems: low catalytic activity, resulting in hydrogen production rates that cannot meet practical application requirements; insufficient hydrogen selectivity, with CO generated from dehydration side reactions easily poisoning fuel cell catalysts; most systems rely on additives such as sodium formate to suppress CO generation, increasing system complexity and cost; the preparation process often requires high temperatures or cumbersome steps, resulting in high energy consumption; and the catalyst has poor cycle stability, with active components easily agglomerating or being lost, limiting its lifespan. Furthermore, traditional supports have limited anchoring effect on metal nanoparticles, making it difficult to simultaneously achieve high dispersibility and structural stability.

[0037] To address the problems existing in the prior art, the present invention provides a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, which is composed of an NH2-rGO support and Pd-Y(OH)3 nanoclusters; the NH2-rGO support is in the form of a sheet, the Pd-Y(OH)3 nanoclusters are loaded on the surface of the NH2-rGO, and Pd and Y(OH)3 form a heterostructure through strong electronic interactions.

[0038] This invention introduces the non-noble metal yttrium (Y) and combines it with palladium to form Pd-Y(OH)3 nanoclusters. By leveraging the structural advantages and basic site effects of aminated graphene oxide (NH2-rGO), this significantly enhances the catalytic activity and hydrogen selectivity in the formic acid dehydrogenation process, effectively suppressing the formation of CO byproducts. Through optimizing the component synergy and structural matching among Pd, Y(OH)3, and NH2-rGO, efficient dispersion of the active components and effective regulation of their electronic structure are achieved. This overcomes the key technical bottlenecks of high cost and insufficient cycle stability inherent in traditional noble metal catalysts while ensuring excellent catalytic performance. This invention provides a feasible material design strategy and synthetic route for developing efficient, economical, and environmentally friendly formic acid to hydrogen production catalyst systems.

[0039] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will provide a detailed description in conjunction with specific embodiments: The graphene oxide used in this invention is prepared using a modified Hummers process, following the steps below: 3g of graphite powder, 2.5g of K2S2O8, 2.5g of P2O5, and 20mL of H2SO4 were added sequentially to a 50mL round-bottom flask to obtain a graphite suspension. The graphite suspension was heated to 353K and stirred at 353K for 4 hours. After stirring, it was allowed to cool naturally to room temperature. Then, it was filtered and separated, washed with sufficient water until neutral, and dried at 333K for 24 hours to obtain pre-oxidized graphite powder.

[0040] The prepared pre-oxidized graphite powder was transferred to a 500 mL round-bottom flask, and 120 mL of concentrated sulfuric acid was added dropwise. After stirring thoroughly at 303 K in an ice bath, a graphite powder suspension was obtained. 15 g of KMnO4 was added dropwise to the graphite powder suspension. After the system turned dark green, it was stirred at 328 K for 6 h. When the color of the system changed from dark green to dark brown, stirring was stopped, and the system was allowed to cool naturally to room temperature. 20 mL of H2O2 was added, and the system immediately turned bright yellow. The system was then washed with deionized water until the pH value was 7, and sonicated for 3 h to obtain a graphene oxide suspension, denoted as GO suspension.

[0041] Example 1 A method for preparing a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, which is prepared by an impregnation-co-reduction method at room temperature, includes the following steps: 23 mg of GO suspension was dispersed in 10 mL of deionized water and placed in a round-bottom flask. After sonication for 30 min, a brown transparent GO dispersion with a mass fraction of 0.23% was obtained. 100 μL of APTMS was added to the 0.23% GO dispersion, and the brown transparent GO dispersion transformed into a dark brown gel-like substance. This was due to the strong interaction between GO and APTMS in the GO dispersion, resulting in an aminated graphene oxide gel, denoted as NH2-rGO.

[0042] To an aminated graphene oxide gel, 1 mL of 0.1 mol / L Na₂PdCl₄ solution and 600 μL of 0.1 mol / L Y(NO₃)₃·6H₂O solution were added sequentially. After stirring continuously for 30 min, 1 mmol of NaBH₄ was rapidly added to remove all Pd... 2+ Restored to Pd, Y 3+ In the alkaline solution produced by the hydrolysis of NaBH4, it is converted to Y(OH)3. After centrifugation and repeated washing with deionized water, Pd-Y(OH)3 / NH2-rGO, a formic acid dehydrogenation catalyst, is obtained and denoted as Pd. .1 Y 0.06 Also recorded as 25wt%.

[0043] Example 2 A method for preparing Pd-Y(OH)3 / NH2-rGO is the same as the method in Example 1, except that the Pd in ​​the palladium precursor solution is removed. 2+ Y in yttrium precursor solution 3+ The molar ratio was changed from 1:0.6 to 1:0.8, that is, the amount of 0.1 mol / L Y(NO3)3·6H2O solution was changed from 600 μL to 800 μL, to obtain the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, denoted as Pd. .1 Y 0.08 .

[0044] Example 3 A method for preparing Pd-Y(OH)3 / NH2-rGO is the same as the method in Example 1, except that the Pd in ​​the palladium precursor solution is removed. 2+ Y in yttrium precursor solution 3+ The molar ratio was changed from 1:0.4 to 1:0.4, that is, the amount of 0.1 mol / L Y(NO3)3·6H2O solution was changed from 600 μL to 400 μL, to obtain the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, denoted as Pd..1 Y 0.04 .

[0045] Example 4 A method for preparing Pd-Y(OH)3 / NH2-rGO is the same as the method in Example 1, except that the Pd in ​​the palladium precursor solution is removed. 2+ Y in yttrium precursor solution 3+ The molar ratio was changed from 1:0.2 to 1:0.2, that is, the amount of 0.1 mol / L Y(NO3)3·6H2O solution was changed from 600 μL to 200 μL, resulting in the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, denoted as Pd. .1 Y 0.02 .

[0046] Example 5 A method for preparing Pd-Y(OH)3 / NH2-rGO is the same as that in Example 1, except that the amount of GO is replaced by 34 mg instead of 23 mg, to obtain Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, denoted as 20 wt%.

[0047] Example 6 A method for preparing Pd-Y(OH)3 / NH2-rGO is the same as that in Example 1, except that the amount of GO is replaced by 16 mg instead of 23 mg, to obtain a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, denoted as 30 wt%.

[0048] Example 7 A method for preparing Pd-Y(OH)3 / NH2-rGO is the same as that in Example 1, except that the amount of GO is replaced by 7 mg instead of 23 mg, to obtain a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, denoted as 40 wt%.

[0049] Example 8 A method for preparing Pd-Y(OH)3 / NH2-rGO is the same as that in Example 1, except that the amount of APTMS solution is replaced by 150 μL instead of 100 μL to obtain the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, denoted as 150 μL.

[0050] Example 9 A method for preparing Pd-Y(OH)3 / NH2-rGO is the same as that in Example 1, except that the amount of APTMS solution is replaced by 200 μL instead of 100 μL to obtain the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, denoted as 200 μL.

[0051] Comparative Example 1 A method for preparing Pd / NH2-rGO is the same as that in Example 1, except that the amount of 0.1 mol / L Y(NO3)3·6H2O solution is replaced with 0 instead of 600 μL to obtain Pd / NH2-rGO, denoted as Pd. .1 .

[0052] Comparative Example 2 A method for preparing Y(OH)3 / NH2-rGO is the same as that in Example 1, except that the amount of 0.1 mol / L Na2PdCl4 solution is replaced by 0 instead of 1 mL to obtain Y(OH)3 / NH2-rGO.

[0053] Comparative Example 3 A method for preparing Pd-Y(OH)3 / rGO is the same as that in Example 1, except that the amount of APTMS solution is replaced by 0 μL instead of 100 μL to obtain Pd-Y(OH)3 / rGO, which is denoted as 0 μL.

[0054] Comparative Example 4 A method for preparing Pd-Y(OH)3 is the same as that in Example 1, except that the amount of GO is replaced by 0 instead of 23 mg and the amount of APTMS solution is replaced by 0 μL instead of 100 μL, thus obtaining Pd-Y(OH)3.

[0055] Comparative Example 5 A method for preparing a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst is the same as that in Example 1, except that the amount of GO is replaced by 87 mg instead of 23 mg, and the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst is obtained, denoted as 10 wt%.

[0056] Comparative Example 6 A method for preparing Pd-Y(OH)3 / NH2-rGO is the same as that in Example 1, except that the amount of APTMS solution is replaced by 50 μL instead of 100 μL to obtain the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, denoted as 50 μL.

[0057] Figure 1 and Figure 2 The results show that in the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1, the particle size of Pd-Y(OH)3 nanoclusters is about 1.0 nm, and they are uniformly dispersed on NH2-rGO.

[0058] like Figure 3 As shown, the characterization results confirm the successful preparation of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst. Analysis indicates a strong electronic coupling between Pd and Y(OH)3, and a strong electron-metal-support interaction (EMSI) between the Pd-Y(OH)3 nanoclusters and NH2-rGO, effectively modulating the electronic structure of the active Pd site and thus significantly improving its catalytic performance.

[0059] In Examples 1-10 of this invention, Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalysts were prepared, and the effects were parallel. The Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalysts of Examples 1-10, Pd / NH2-rGO of Comparative Example 1, and Pd-Y(OH)3 / rGO of Comparative Example 3 were used as catalysts to catalyze the decomposition of formic acid to produce hydrogen, and their catalytic performance was studied. Application method: The catalyst was dispersed in deionized water to obtain catalytic suspensions, and the preset reaction temperature was maintained at 50°C. 2 mL of 1.25 mol / L formic acid solution was added to each catalytic suspension. The volume of generated gas was monitored by a gas measuring tube to characterize the dehydrogenation activity of the catalyst. After each reaction, 2 mL of 1.25 mol / L formic acid solution was added directly to the reaction system to allow the catalyst to participate in the next dehydrogenation reaction, in order to evaluate its durability.

[0060] Depend on Figure 4 It was found that, under the conditions of 323K and no additives, the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1 exhibited excellent catalytic activity for formic acid decomposition, with a turnover frequency (TOF) as high as 2628.9 / h.

[0061] Depend on Figure 5 It was found that, under conditions of 323 K and no additives, the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1 can achieve 100% H2 selectivity in the decomposition of formic acid.

[0062] Figure 6 The results show that in the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1, the incorporation of Y(OH)3 effectively reduced the activation energy barrier of the formic acid decomposition reaction and significantly improved the kinetic performance of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst.

[0063] Figure 7 The results show that the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1 has excellent durability, and its catalytic activity did not show significant decay after 10 consecutive cycles.

[0064] Figure 8 The results show that the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst of Example 1 has a stable structure. After multiple cycles of reaction, the size of the active metal nanoclusters only increased slightly to about 2.5 nm, but still remained uniformly distributed on NH2-rGO.

[0065] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst, characterized in that, The Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst is composed of an NH2-rGO support and Pd-Y(OH)3 nanoclusters. The NH2-rGO support is in the form of a sheet, and the Pd-Y(OH)3 nanoclusters are loaded on the surface of the NH2-rGO. Pd and Y(OH)3 form a heterostructure through strong electronic interactions.

2. A method for preparing the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst according to claim 1, characterized in that, Includes the following steps: Ammoniated graphene oxide gel, palladium precursor solution, and yttrium precursor solution were mixed to obtain a Pd-containing solution. 2+ and Y 3+ Precursor solution; When NaBH4 is mixed with the precursor solution and a reduction reaction is carried out, NaBH4 hydrolyzes to produce OH-. - Pd in ​​the precursor solution 2+ It is reduced to Pd, while Y 3+ In-situ precipitation yields Y(OH)3, resulting in a Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst; at this point, Pd and Y(OH)3 are dispersed on aminated graphene oxide in the form of Pd-Y(OH)3 nanoclusters.

3. The preparation method according to claim 2, characterized in that, The mass ratio of aminated graphene oxide in the aminated graphene oxide gel to palladium in the palladium precursor solution is 1:0.2~2.

4. The preparation method according to claim 2, characterized in that, In the precursor solution, Pd 2+ With Y 3+ The molar ratio is 1:0.2~0.

8.

5. The preparation method according to claim 2, characterized in that, Pd in ​​palladium precursor solution 2+ The molar ratio with NaBH4 is 1:10~20.

6. The preparation method according to claim 2, characterized in that, The conditions for the reduction reaction are: stirring at room temperature until no more H2 is produced in the system.

7. The preparation method according to claim 2, characterized in that, Aminated graphene oxide gel was prepared according to the following steps: A graphene oxide dispersion was mixed with an aminosilane coupling agent at room temperature to obtain an amino-modified graphene oxide gel, namely NH2-rGO; wherein the mass ratio of graphene oxide to aminosilane coupling agent in the graphene oxide dispersion was 1:2~8.

8. The preparation method according to claim 7, characterized in that, The aminosilane coupling agent is selected from (3-aminopropyl)trimethoxysilane or (3-aminopropyl)triethoxysilane.

9. The application of the Pd-Y(OH)3 / NH2-rGO formic acid dehydrogenation catalyst according to claim 1 in the catalytic decomposition of formic acid to produce hydrogen.

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