CN-121988361-A - Quantum dot modified Pt/SiC catalyst and preparation and activation methods and application thereof

CN121988361ACN 121988361 ACN121988361 ACN 121988361ACN-121988361-A

Abstract

The invention belongs to the technical field of catalysts, and particularly discloses a quantum dot modified Pt/SiC catalyst, and a preparation and activation method and application thereof. The quantum dot modified SiC is used as a carrier of the catalyst, pt is loaded on the surface of the carrier by a liquid phase reduction method, the quantum dot modified Pt/SiC catalyst is obtained, and the adsorption of C=O in cinnamaldehyde is enhanced by the modification of CeO 2 QDs. The method for improving the hydrogenation performance by utilizing the hydrogen overflow activated catalyst is provided, the activated and pretreated Pt/CeO 2 QDs-SiC catalyst further enhances the adsorption of C=O and improves the hydrogenation selectivity, and the efficient selective hydrogenation of cinnamaldehyde can be realized under milder conditions to generate cinnamyl alcohol.

Inventors

JIAO ZHIFENG
Gong Qianwen
ZHAO JIXIAO
GUO XIANGYUN
QIAN JUNFENG
SUN ZHONGHUA

Assignees

常州大学

Dates

Publication Date: 20260508
Application Date: 20260116

Claims (10)

1. A quantum dot modified Pt/SiC catalyst is characterized in that the catalyst is a carrier taking quantum dot modified SiC as a catalyst, pt is loaded on the surface of the carrier through a liquid phase reduction method, and the quantum dot modified Pt/SiC catalyst is obtained, wherein the content of quantum dots in the quantum dot modified SiC catalyst is 1-20wt.%, and the content of platinum in the quantum dot modified Pt/SiC catalyst is 0.1-3wt.%.
2. A method of preparing a quantum dot modified Pt/SiC catalyst as claimed in claim 1, comprising the steps of: (1) Mixing quantum dots, siC and water, performing ultrasonic oscillation for 0.5-3 hours, transferring into a hydrothermal kettle, performing heating reaction, and performing centrifugal washing to obtain quantum dot modified SiC; (2) Mixing and stirring the H 2 PtCl 4 ·6H 2 O solution and quantum dot modified SiC for 30min, then dropwise adding the lysine solution and stirring for 30min, finally dropwise adding the sodium borohydride solution and dilute hydrochloric acid and stirring for 12H, filtering, washing and drying to obtain the quantum dot modified Pt/SiC catalyst.
3. The method for preparing the quantum dot modified Pt/SiC catalyst according to claim 2, wherein the quantum dot comprises one of TiO 2 QDs、SnO 2 QDs、CeO 2 QDs、MnO 2 , and the mass fraction of the quantum dot is 0.1-20wt.% of SiC.
4. The method for preparing the quantum dot modified Pt/SiC catalyst according to claim 2, wherein the heating reaction temperature in the step (1) is 150-300 ℃ and the heating time is 6-24 hours.
5. The method for preparing a quantum dot modified Pt/SiC catalyst according to claim 2, wherein the concentration of the H 2 PtCl 4 ·6H 2 O solution in the step (2) is 4 mg/mL -1 , the molar concentration of the lysine solution is 0.53mol/L, the molar concentration of the sodium borohydride solution is 0.35mol/L, the molar concentration of the dilute hydrochloric acid is 0.3mol/L, and the volume ratio of the lysine solution, the sodium borohydride solution and the dilute hydrochloric acid is 2:1:1.
6. A method for activating the quantum dot modified Pt/SiC catalyst according to claim 1, which is characterized in that an ethanol solvent and the quantum dot modified Pt/SiC catalyst according to claim 1 are uniformly mixed to form a suspension, the suspension is transferred into a high-temperature high-pressure reaction kettle to be sealed, after the suspension is purged by hydrogen, the reaction kettle is maintained at a hydrogen pressure of 1MPa and a temperature of 40 ℃ for 1h under stirring, the catalyst is activated by utilizing hydrogen overflow, and then the reaction kettle is filtered and dried for reaction.
7. The application of the quantum dot modified Pt/SiC catalyst according to claim 1 in preparing cinnamyl alcohol by selectively hydrogenating cinnamyl aldehyde, which is characterized in that cinnamyl aldehyde, an organic solvent and the catalyst obtained by activating the method according to claim 6 are uniformly mixed to form a suspension, the suspension is transferred into a high-temperature high-pressure reaction kettle to be sealed, the reaction kettle is maintained at the hydrogen pressure of 0.5-2MPa after being purged by hydrogen, and the reaction is carried out for 1-6 hours under the stirring condition at 20-80 ℃ to prepare the cinnamyl alcohol by selectively hydrogenating the cinnamyl aldehyde.
8. The application of the quantum dot modified Pt/SiC catalyst for preparing cinnamyl alcohol by selective hydrogenation of cinnamyl aldehyde, which is disclosed in claim 7, wherein the molar concentration of the cinnamyl aldehyde in a suspension is 0.1mol/L, and the mass ratio of the cinnamyl aldehyde to the quantum dot modified Pt/SiC catalyst is 1:0.1-0.5.
9. The use of the quantum dot modified Pt/SiC catalyst of claim 7 in selective hydrogenation of cinnamaldehyde to produce cinnamyl alcohol, wherein the organic solvent is one of ethanol, methanol, isopropanol, acetonitrile or n-hexane.
10. Use of the quantum dot modified Pt/SiC catalyst of claim 1 in the hydrogenation of p-nitrobenzene or benzonitrile.

Description

Quantum dot modified Pt/SiC catalyst and preparation and activation methods and application thereof Technical Field The invention belongs to the technical field of catalyst preparation, and particularly relates to a quantum dot modified Pt/SiC catalyst, and a preparation method, an activation method and an application thereof, and a method for activating and preprocessing the catalyst. More particularly, to the application thereof in the preparation of cinnamyl alcohol by selective hydrogenation of cinnamyl aldehyde. Background Catalytic hydrogenation is an important class of processes in petrochemical, coal chemical and fine chemical industries. In the synthesis of fine chemicals and pharmaceuticals, it is often encountered that multiple unsaturated functionalities are simultaneously contained in the same reactant molecule, and achieving selective hydrogenation of a particular one of the functionalities is a challenging task. Selective hydrogenation of α, β -unsaturated aldehydes to produce α, β -unsaturated alcohols is challenging. Because the bond energy of the c=o bond in the molecule is larger, hydrogenation is more difficult from a thermodynamic point of view. Meanwhile, competitive adsorption of c=c bonds and c=o bonds on the catalyst surface also results in lower selectivity for a particular product. The noble metal catalyst has higher activity in the selective hydrogenation reaction of cinnamaldehyde, wherein Pt, au and Ir And Ru is mainly used for hydrogenation of c=o bond, pt is widely used for hydrogenation reaction due to its unique electronic structure and excellent H 2 dissociation capability, and in order to further improve cinnamyl alcohol selectivity, morphology and electronic state of Pt are adjusted to improve catalytic performance. Zhao Jixiao et al (CHEMISTRYSELECT, 2025, 10 (10): e 202406114) studied and reported that Pt/SiC-HNO 3 catalysts, which achieved 89% CAL conversion and 87% COL selectivity by treating Pt catalysts supported on surface oxidized SiC with HNO 3, contributed to the superior performance in CAL hydrogenation by the presence of a higher proportion of Pt 0 in favor of H 2 as Pt/SiC-HNO 3 catalysts. Selective hydrogenation is a core technology in chemical production. However, how to achieve near complete conversion of the reactants while still maintaining high selectivity to the target product has been a challenge to be addressed. To address this challenge, researchers have developed numerous high performance hydrogenation catalysts through a variety of approaches, including modulating the electronic structure, exploiting the synergy between metals and supports, and the like. Nevertheless, these carefully constructed catalysts often face problems of structural or chemical instability under the actual reaction conditions, making it difficult to maintain both high catalytic activity and high selectivity in the application. While hydrogen flooding provides a viable path for dynamic adjustment of catalytic performance during the reaction, the active sites generated in situ tend to suffer from incomplete conversion or maldistribution limitations, which directly limit further increases in selectivity. Redina E A et al (J. Catal. 2024; 429: 115231) studied a Pt catalyst based on CeO 2-ZrO2 loading and used highly selective hydrogenation of alpha, beta-unsaturated aldehydes at normal temperature and pressure to prepare unsaturated alcohols. The research shows that the CeO 2-ZrO2 carrier can stabilize Pt to form ultra-small clusters, promote hydrogen to generate heterolysis and dissociation on Pt to generate hydride anions (H-) instead of hydrogen radicals, prove the existence of hydride species, and reveal the key effect of the hydride species on selective hydrogenation of C=O, thereby finally realizing high-activity, high-selectivity and recyclable catalytic performance. In their study, the catalyst was pretreated in a hydrogen stream at 230 ℃ for 120 minutes prior to testing. This pretreatment method, on the effective back, risks altering the intrinsic structure of the catalyst, which may impair its preset functional characteristics. Disclosure of Invention We propose a strategy to adjust the adsorption sites of c=o groups in situ using the hydrogen flooding effect. The catalyst is pretreated by mild condition activation, so that the efficient selective hydrogenation of cinnamaldehyde to generate cinnamyl alcohol can be realized under milder conditions. In order to achieve the purpose of the invention, the invention provides the following technical scheme: The quantum dot modified Pt/SiC catalyst is prepared by taking quantum dot modified SiC as a carrier of the catalyst and loading Pt on the surface of the carrier through a liquid phase reduction method, wherein the content of quantum dots in the quantum dot modified SiC catalyst is 1-20wt%, and the content of platinum in the quantum dot modified Pt/SiC catalyst is 0.1-3wt%. The prepared catalyst is used for reaction after