CN-118045591-B - Preparation method, product and application of BN coated Ni catalyst

Abstract

The invention provides a preparation method, a product and application of a BN coated Ni catalyst. The preparation method comprises the steps of depositing BN on the surface of a Ni substrate by a vapor deposition method, preparing the BN coated Ni catalyst, adjusting the electronic environment of B by utilizing the interaction between Ni and B, increasing the reaction activity, reducing the temperature required by the reaction, realizing excellent low-temperature high-activity high-selectivity propane oxidative dehydrogenation performance, simultaneously, ensuring that foam nickel has very good pore structure and heat conduction property, preventing heat in the reaction process from accumulating at a certain point, preventing the occurrence of local hot spot phenomenon of the catalyst, and finally, providing sites for vapor free radical reaction by using rich pores of the foam nickel besides the surface reaction, and increasing the activity of the reaction from another way.

Inventors

• YAO SIYU
• GAO XIAOFENG
• HUANG YONGKANG

Assignees

• 浙江大学

Dates

Publication Date

20260505

Application Date

20221115

Claims (6)

1. 1. The application of the BN coated Ni catalyst in the oxidative dehydrogenation of propane is characterized in that the preparation method of the BN coated Ni catalyst comprises the following steps: Introducing a nitrogen source and a boron source into a reactor with a Ni substrate to deposit respectively by adopting a vapor deposition method, and carrying out high-temperature heat treatment on a reaction product after the deposition reaction is finished to obtain the BN coated Ni catalyst; the Ni substrate is foam nickel.
2. 2. The application of the BN coated Ni catalyst according to claim 1 in the oxidative dehydrogenation of propane, wherein the volume flow ratio of the nitrogen source to the boron source is (0.1-10): 1.
3. 3. The use of BN-coated Ni catalyst according to claim 1, in oxidative dehydrogenation of propane, characterized in that the deposition reaction temperature is 600-1400 ℃ for 0.5-5 h.
4. 4. The use of BN-coated Ni catalyst according to claim 1, in oxidative dehydrogenation of propane, characterized in that the residence time of nitrogen source and boron source is 0.01-10 s during the deposition reaction.
5. 5. Use of BN coated Ni catalyst according to claim 1 in the oxidative dehydrogenation of propane, wherein the nitrogen source is ammonia gas; The boron source is one or more of boron chloride, boron bromide and boron iodide.
6. 6. The application of the BN coated Ni catalyst according to claim 1 in the oxidative dehydrogenation of propane, wherein the high temperature heat treatment temperature is 1000-1600 ℃.

Description

Preparation method, product and application of BN coated Ni catalyst Technical Field The invention belongs to the technical field of catalytic chemical industry, and particularly relates to a preparation method, a product and application of a BN coated Ni catalyst. Background Propylene, the second largest organic olefin chemical next to ethylene, is a very important chemical raw material and polymer monomer, and has wide application and great demands in the synthesis of products such as polypropylene, propylene oxide, acrylonitrile, acrylic acid, cumene, butanol and the like. The current sources of propylene include petroleum based naphtha cracking and catalytic cracking, fischer-Tropsch synthesis to make olefins, methanol to make propylene, propane dehydrogenation to make propylene, and the like. In contrast, the propylene production route by dehydrogenation of propane is economically feasible and environmentally friendly, and is considered to be a very promising and economically competitive propylene production technology. The propane dehydrogenation technology is divided into direct dehydrogenation and oxidative dehydrogenation, wherein the oxidative dehydrogenation of propane is an exothermic process, the thermodynamic equilibrium limit is not existed, and the propane dehydrogenation technology is carried out in an oxidizing atmosphere, and has the advantages of no carbon deposit, high reaction rate, low reaction temperature and the like. In 2016, the us scientist Hermans et al first used commercial hexagonal boron nitride (h-BN) and Boron Nitride Nanotubes (BNNTs) as nonmetallic catalysts in propane oxidative dehydrogenation, showing excellent catalytic performance, and received extensive attention from researchers. After that, how to design the boron-based catalyst, explore the reaction mechanism and structure-activity relationship, and further improve the olefin selectivity and yield of the catalyst is the key point of research. Propane oxidative dehydrogenation is an exothermic reaction, so that local hot spots of the catalyst are easily formed in the reaction process, the adverse phenomena of active component sintering, surface coking increase and the like are caused, and the activity of the catalyst is reduced. In addition, the boron-based catalyst has poor low-temperature activity, and the reaction at high temperature not only increases the energy consumption, but also can lead to the increase of CO x as a peroxidation product and reduce the selectivity, which are all problems to be solved urgently. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a preparation method of a BN coated Ni catalyst, which adopts a vapor deposition method to deposit boron nitride on the surface of a Ni substrate to prepare the boron nitride coated Ni catalyst. The catalyst with the structure adjusts the electronic environment of B by utilizing the interaction between Ni and B, increases the reactivity of boron nitride, reduces the temperature required by the reaction, and realizes excellent low-temperature high-activity high-selectivity of propane oxidative dehydrogenation reaction. In addition, the invention also provides an application of the BN coated Ni catalyst prepared by the preparation method in the oxidative dehydrogenation of propane. A preparation method of BN coated Ni catalyst comprises the following steps: And (3) respectively introducing a nitrogen source and a boron source into the reactor with the Ni substrate by adopting a vapor deposition method to deposit, and carrying out high-temperature heat treatment on a reaction product after the deposition reaction is finished to obtain the BN coated Ni catalyst. According to the preparation method, the boron nitride coating layer is deposited on the surface of the Ni substrate by adopting a vapor deposition method, the electronic environment of B is adjusted by utilizing the interaction between Ni and B, the reactivity of the B is increased, the temperature required by the reaction is reduced, and the excellent low-temperature high-activity high-selectivity propane oxidative dehydrogenation performance is realized. Preferably, the Ni substrate is one or more of foam nickel, nickel foil and nickel particles. Further preferred is nickel foam. The foam nickel has excellent pore structure and heat conductivity, can effectively prevent heat accumulation at a certain point in the oxidative dehydrogenation reaction process of propane, avoids the occurrence of local hot spot phenomenon of a catalyst, and besides, besides surface reaction, the rich pores of the foam nickel provide places for gas phase free radical reaction, thereby increasing the reaction activity from another way. Preferably, the volume flow ratio of the nitrogen source to the boron source is (0.1-10): 1. Further preferably (1 to 5): 1. Further preferably (2-4): 1. Preferably, the temperature of the deposition reaction is 600-1400 ℃. Further preferably