Photocatalyst for preparing 2, 5-furandicarboxaldehyde as well as preparation method and application of photocatalyst

Abstract

The invention relates to the technical field of biomass catalytic conversion, in particular to a photocatalyst for preparing 2, 5-furandicarboxaldehyde and a preparation method and application thereof.The preparation method comprises the steps that Bi (NO3) 3.5 H2O and KBr are weighed and dissolved in ultrapure water under the assistance of ultrasonic waves, and the solutions are marked as a solution A and a solution B respectively; then, under the condition of continuous stirring, dropwise adding the solution B into the solution A, further stirring for 2 hours, centrifuging to obtain sample powder, washing the sample powder with deionized water and ethanol for 3 times respectively, and finally drying the sample powder in a vacuum oven at 60 DEG C for 12 hours to obtain the oxygen vacancy-free photocatalyst BiOBr-(001) of which the exposed crystal face is a (001) face. The catalyst provided by the invention has high photon-generated carrier transmission and separation efficiency and strong oxygen adsorption capacity, is beneficial to generation of. O2 <->, and is simple in preparation method and low in cost; under the illumination condition of 400 nm, air is used as an oxygen source at normal temperature and normal pressure, acetonitrile is used as a solvent, efficient catalytic conversion preparation of DFF by using HMF as a substrate can be realized, and the method has good recoverability.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass catalytic conversion, and particularly relates to a photocatalyst for preparing 2,5-furandicarboxaldehyde, a preparation method thereof, and an application thereof. Background Art

[0002] The catalytic conversion of biomass-derived platform molecules into liquid fuels and high-value-added chemicals plays a crucial role in promoting global carbon neutrality. Among numerous platform compounds, 5-hydroxymethylfurfural (HMF) shows great application potential, which can be further oxidized to generate high-value-added chemicals such as 2,5-furandicarboxaldehyde (DFF), 5-hydroxymethyl-2-furancarboxylic acid, 5-formyl-2-furancarboxylic acid, and 2,5-furandicarboxylic acid. Among them, DFF is an important upstream raw material for pharmaceutical intermediates, antibacterial agents, adhesives, fluorescent agents, polyethylene, and biomass-based resins. However, due to the coexistence of active functional groups in HMF, including aldehyde groups, hydroxyl groups, and furan rings, it is extremely challenging to selectively partially oxidize hydroxymethyl to prepare DFF, and this process needs to avoid the over-oxidation or even mineralization of HMF.

[0003] According to the energy source of the catalytic system, the current approaches for selectively catalytically oxidizing HMF to prepare DFF are mainly thermal catalysis and electrocatalysis, but both have economic, safety, and environmental problems. In contrast, photocatalysis, as a more environmentally friendly and sustainable catalytic route, can utilize solar energy to achieve cost-effective and net-zero conversion for chemical production. However, in most HMF photocatalytic oxidation systems, the reaction efficiency is often limited due to the slow kinetics of photo-generated charges and the uncontrollability of reactive oxygen species (ROS). In Chinese patent document CN117551063A, using the bimetallic sulfide Z-scheme heterojunction SnIn4S8-ZnIn2S4 as the catalyst, reacting for 3 h under light illumination of 400 nm or more, the selectivity of DFF is only 74.3%. In Chinese patent document CN111087371A, using MAPbBr3 as the catalyst, the complete conversion of HMF can be achieved only by reacting for 10 h under light illumination of 450 nm, and the selectivity of DFF is 90 ± 1.2%. In Chinese patent document CN116037166A, a Pt-Ov-BiOBr catalyst with an interfacial Pt-O bond is constructed by photo-depositing noble metal platinum on bromine oxygen bismuth with oxygen vacancies, which is beneficial to the generation of superoxide radicals (·O2 - ) Under light illumination of 420 nm and oxygen supply conditions, the conversion rate of HMF can reach 91.5% after reacting for 3 h, and the selectivity of DFF is 76.7% at the same time. However, the introduction of noble metals undoubtedly increases the preparation cost. In the HMF photocatalytic oxidation system, ·O2 -It has mild oxidation ability and is widely regarded as the main ROS for the photooxidation of HMF to DFF, which is mainly obtained by the reduction of oxygen. Therefore, to construct an economical and efficient photocatalytic system for the oxidation of HMF to prepare DFF, it is crucial to improve the separation efficiency of photo-generated carriers and the selectivity of ·O2 - . Summary of the Invention

[0004] The object of the present invention is to provide a photocatalyst for the preparation of 2,5-furandicarboxaldehyde, its preparation method and application. Aiming at the problems of low selectivity of the target product DFF, slow generation rate and high catalyst preparation cost in the prior art, the catalyst proposed by the present invention has high photo-generated carrier transport and separation efficiency, strong oxygen adsorption ability, which is beneficial to the generation of ·O2 - . Under the condition of light with wavelength λ>400nm, using air as the oxygen source and acetonitrile as the solvent at normal temperature and pressure, HMF can be efficiently catalytically converted to prepare DFF, and it has good recyclability.

[0005] To achieve the above technical objectives and reach the above technical effects, the present invention is realized through the following technical solutions:

[0006] A photocatalyst for the preparation of 2,5-furandicarboxaldehyde, the photocatalyst includes but is not limited to BiOBr-(001), OV-BiOBr-(001 / 110), OV-BiOBr-(110).

[0007] Further, the photocatalyst is OV-BiOBr-(110).

[0008] On the other hand, the present invention proposes a preparation method of the above photocatalyst, including:

[0009] Weigh Bi(NO3)3·5H2O and KBr, and dissolve them in ultrapure water under ultrasonic assistance respectively, and record them as solution A and solution B; then, under continuous stirring, add solution B dropwise to solution A, stir for another 2h, and centrifuge to obtain the sample powder, and wash it 3 times with deionized water and ethanol respectively. Finally, dry it in a vacuum oven at 60°C for 12h to obtain a photocatalyst BiOBr-(001) without oxygen vacancies with the exposed crystal plane being the (001) plane.

[0010] Further, by changing the solvent of Bi(NO3)3·5H2O to ethylene glycol, a photocatalyst OV-BiOBr-(001 / 110) with the exposed crystal plane being the (001 / 110) plane and containing oxygen vacancies can be obtained.

[0011] Furthermore, adding cetyltrimethylammonium bromide can obtain a photocatalyst OV-BiOBr-(110) with the exposed crystal plane being the (110) plane and containing oxygen vacancies.

[0012] On the other hand, the present invention provides a method for preparing 2,5-furandicarboxaldehyde by oxidizing 5-hydroxymethylfurfural using the above photocatalyst, which includes: adding the photocatalyst and an 8 mM 5-hydroxymethylfurfural solution (using acetonitrile as the solvent) into a quartz photoreactor, ultrasonically treating for 30 min under dark conditions, and continuously irradiating for 2 h at a rotation speed of 450 rpm to obtain 2,5-furandicarboxaldehyde.

[0013] The beneficial effects of the present invention:

[0014] In the BiOBr photocatalyst of the present invention, especially OV-BiOBr-(110), by introducing oxygen vacancies on the (110) crystal plane, the transport and separation efficiency of photogenerated carriers are significantly enhanced. This design greatly reduces the recombination probability of electrons and holes because oxygen vacancies can effectively capture and separate photogenerated electrons, preventing carrier recombination on the surface. At the same time, the (110) crystal plane structure is beneficial to the uniformity of the distribution of electrons inside the catalyst, improving the carrier mobility. This improvement reduces energy loss during the photocatalytic process, enabling more light energy to be used for catalyzing the conversion of HMF and increasing the yield and selectivity of DFF.

[0015] In OV-BiOBr-(110), oxygen vacancies not only serve as sites for capturing photogenerated electrons but also greatly improve the oxygen adsorption capacity. These oxygen vacancies can activate the adsorbed oxygen molecules and promote the generation of superoxide radicals (·O2 - ). These reactive oxygen species are the key reactive intermediates for oxidizing HMF to DFF. The synergistic effect between oxygen vacancies and surface atoms improves the molecular adsorption and dissociation ability of oxygen, so that an efficient oxidation reaction can be achieved at normal temperature and pressure. Through this mechanism, the catalyst shows efficient utilization of oxygen, improving the conversion efficiency of HMF and the selectivity of DFF.

[0016] The photocatalyst of the present invention is prepared by a simple mechanical stirring method, using common and inexpensive chemical reagents such as Bi(NO3)3·5H2O and KBr, and combining with ultrasonic assistance technology to optimize the reaction uniformity and the morphology of the generated particles. Compared with traditional high-temperature calcination or complex chemical vapor deposition methods, this method significantly reduces the production cost and energy consumption. In addition, by adjusting the reaction medium (such as ethylene glycol) and additives (such as cetyltrimethylammonium bromide), the surface structure and oxygen vacancies of the catalyst can be flexibly regulated, and the production process is simple and easy to scale up for promotion. Thus, the prepared catalyst is not only highly optimized in structure, but also greatly reduced in cost and complexity.

[0017] The OV-BiOBr-(110) of the present invention exhibits excellent catalytic performance under light irradiation, achieving a conversion rate of up to 94.0% of HMF and a selectivity of 99.0% of DFF. This benefits from the formation of efficient active centers on its surface and the optimized electronic structure. In addition, the catalyst demonstrates excellent structural stability and durability. In multiple reaction cycles, the catalyst can be reused after simple washing and drying, and there is no significant decrease in its catalytic activity and selectivity. The conversion rate and selectivity still remain above 80% after four cycles of use. This excellent recyclability not only extends the service life of the catalyst but also reduces the waste treatment cost, providing an economically effective solution for industrial applications.

[0018] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is the high-resolution transmission electron microscope images of different catalysts in the present invention.

[0021] Figure 2 It is the X-ray diffraction spectra of different catalysts in the present invention.

[0022] Figure 3 It is the electron paramagnetic resonance spectra of different catalysts in the present invention.

[0023] Figure 4 It is the photoluminescence spectra of different catalysts in the present invention.

[0024] Figure 5 It is the oxygen adsorption and desorption spectra of different catalysts in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0026] Example 1

[0027] The specific preparation method of a photocatalyst for the oxidation of HMF to prepare DFF in this embodiment is as follows:

[0028] Weigh 0.36 g of Bi(NO3)3·5H2O and 0.89 g of KBr, and dissolve them in 30 mL of ultrapure water under ultrasonic assistance, which are respectively denoted as solution A and solution B. Subsequently, under continuous stirring, solution B is added dropwise to solution A. After further stirring for 2 h, the sample powder is obtained by centrifugation, and washed 3 times with deionized water and ethanol respectively. Finally, it is dried in a vacuum oven at 60 °C for 12 h to obtain a photocatalyst BiOBr-(001) without oxygen vacancies with the exposed crystal plane being the (001) plane. By replacing the solvent of Bi(NO3)3·5H2O with ethylene glycol, a photocatalyst OV-BiOBr-(001 / 110) with the exposed crystal plane being the (001 / 110) plane and containing oxygen vacancies can be obtained. On this basis, by adding 0.1 g of cetyltrimethylammonium bromide, a photocatalyst OV-BiOBr-(110) with the exposed crystal plane being the (110) plane and containing oxygen vacancies can be obtained.

[0029] Example 2

[0030] In this embodiment, the catalyst obtained in Example 1 above is used for the photocatalytic preparation of DFF from HMF;

[0031] 30 mg of the catalyst and 5 mL of 8 mM HMF solution (using acetonitrile as the solvent) are added to a quartz photoreactor, ultrasonically treated for 30 min under dark conditions, sampled after continuous light irradiation at a rotation speed of 450 rpm for 2 h, and analyzed by HPLC. The catalytic detection results of different catalysts are listed as numbers 1 - 3 in Table 1.

[0032] 10 - 40 mg of OV-BiOBr-(110) and 5 mL of 8 mM HMF solution (using acetonitrile as the solvent) are added to a quartz photoreactor, ultrasonically treated for 30 min under dark conditions, sampled after continuous light irradiation at a rotation speed of 450 rpm for 0.5 - 2.5 h, and analyzed by HPLC. The catalytic detection results under different reaction conditions are listed as numbers 4 - 12 in Table 1.

[0033] For the OV-BiOBr-(110) catalyst in the above experiment with a reaction time of 2 h, after the reaction, it is centrifuged and collected, washed 3 times with deionized water and ethanol respectively, and dried in a vacuum oven at 60 °C for 12 h, and directly used for the next catalytic reaction. The catalytic conditions are as follows: 30 mg of the recycled OV-BiOBr-(110) and 5 mL of 8 mM HMF solution (using acetonitrile as the solvent) are added to a quartz photoreactor, ultrasonically treated for 30 min under dark conditions, sampled after continuous light irradiation at a rotation speed of 450 rpm for 2 h, and analyzed by HPLC. The detection results of the catalytic effects of the catalyst with different recycling times are listed as numbers 13 - 16 in Table 1.

[0034] Table 1

[0035]

[0036] In summary, the present invention prepares a bismuth oxybromide photocatalyst with different exposed crystal planes and oxygen vacancies by a simple mechanical stirring method, and uses it for the photocatalytic oxidation of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxaldehyde. Bismuth oxybromide with exposed (110) crystal planes and oxygen vacancies exhibits high photo-generated carrier transport and separation efficiency, strong oxygen adsorption ability, which is beneficial to the generation of reactive oxygen species superoxide radicals. Under the illumination condition of wavelength λ>400nm, using air as the oxygen source at normal temperature and pressure, 94.0% conversion of 5-hydroxymethylfurfural can be achieved, and the selectivity of DFF is as high as 99.0%. After recycling 4 times, the conversion rate and selectivity can still remain above 80%.

[0037] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A photocatalyst for preparing 2,5-furandicarboxaldehyde, characterized in that: The photocatalyst includes but is not limited to BiOBr-(001), OV-BiOBr-(001 / 110), and OV-BiOBr-(110).

2. The photocatalyst for preparing 2,5-furandicarboxaldehyde according to claim 1, characterized in that: The photocatalyst is OV-BiOBr-(110).

3. The method for preparing a photocatalyst according to claim 1 or 2, characterized in that: include: Bi(NO3)3·5H2O and KBr were weighed and dissolved in ultrapure water under the assistance of ultrasound, respectively, and recorded as solution A and solution B, respectively; then, solution B was added dropwise into solution A under constant stirring, and after further stirring for 2 hours, the sample powder was obtained by centrifugation, and washed with deionized water and ethanol for 3 times, respectively, and finally dried in a vacuum oven at 60°C for 12 hours to obtain an oxygen vacancy-free photocatalyst BiOBr-(001) with an exposed crystal plane of (001) plane.

4. The preparation method according to claim 3, characterized in that: The Bi(NO3)3·5H2O solvent was replaced with ethylene glycol, and finally the photocatalyst OV-BiOBr-(001 / 110) with an exposed crystal plane of (001 / 110) and containing oxygen vacancies was obtained.

5. The preparation method according to claim 4, characterized in that: Then 0.1 g of hexadecyltrimethylammonium bromide was added, and finally the photocatalyst OV-BiOBr-(110) with the exposed crystal face as (110) and containing oxygen vacancies was obtained.

6. The method for preparing 2,5-furandicarboxaldehyde by oxidizing 5-hydroxymethylfurfural using the photocatalyst as claimed in claim 1 or 2, characterized in that: include: The photocatalyst and 8 mM 5-hydroxymethylfurfural solution were added into a quartz photoreactor, ultrasonicated for 30 min in the dark, and continuously illuminated for 2 h at a rotation speed of 450 rpm to obtain 2,5-furandicarboxaldehyde.

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