CN116099543B - Vanadium-iron-based bimetallic oxide catalyst and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of chemical chain low-carbon alkane dehydrogenation catalysts, and discloses a vanadium iron-based bimetallic oxide catalyst, a preparation method and application thereof, wherein the catalyst is FeVO ₄ with single-layer dispersion supported on a carrier, and FeVO ₄ nano particles with single-layer dispersion supported on FeVO ₄ with bulk phase; the single-layer dispersed FeVO ₄ is used as a direct dehydrogenation catalytic site, and the FeVO ₄ nano-particles are used as hydrogen selective combustion sites; the preparation method comprises the steps of firstly dissolving and uniformly mixing precursor salt of iron and precursor salt of vanadium; then dipping the uniformly mixed salt solution on a carrier for drying; finally, roasting, and tabletting, forming and sieving the roasted catalyst for standby. The catalyst is applied to the chemical chain dehydrogenation of the low-carbon alkane, and has the outstanding advantages of high single-pass conversion rate of the low-carbon alkane and high selectivity of the target product alkene; meanwhile, the problem of sintering of pure ferric oxide in the oxidation-reduction process can be effectively solved, and the performance and the structure of the pure ferric oxide can be kept stable after a plurality of reduction-oxidation regeneration cycles are realized.

Description

Vanadium-iron-based bimetallic oxide catalyst and its preparation method and application

Technical Field

The present invention belongs to the technical field of chemical chain low-carbon alkane dehydrogenation catalysts, and specifically relates to a supported vanadium-iron-based bimetallic oxide catalyst and a preparation method and application thereof.

Background Art

As one of the three basic raw materials for synthetic materials, the demand gap for propylene continues to expand globally. The traditional propylene production technology based on light oil cracking and heavy oil catalytic cracking can no longer meet market requirements and the development of a low-carbon economy due to its high energy consumption and large carbon emissions. Therefore, the development of new propylene production technology is imminent. The success of the "shale gas revolution" in the United States has provided new opportunities for the development of a low-carbon economic strategy. The development of shale gas has produced a large amount of cheap low-carbon alkanes, which has brought hope for the preparation of corresponding high-value-added olefins.

Using propane as raw material, propane oxygen-free dehydrogenation (PDH) as a new method for on-purpose propylene production has attracted the attention of many researchers. In the current commercial PDH processes at home and abroad (mainly Catofin and Oleflex processes), chromium oxide and platinum-based catalysts are used respectively. However, the toxic CrO _x and expensive Pt-based catalysts, as well as the inherent thermodynamic equilibrium limitations and high energy consumption of the endothermic reaction, have prompted researchers to explore new technologies for the production of propylene from propane that are more efficient, environmentally friendly, low-carbon, and economical. Propane oxidative dehydrogenation (ODHP) can effectively break the thermodynamic limitations by introducing oxidants (such as oxygen, carbon dioxide, and nitrous oxide) into the reaction system, and is a potential method for propylene production. However, the safety hazards of the reactant propane and the product propylene tending to be over-oxidized to CO ₂ and the mixing of reducing and oxidizing gases have raised big questions about the feasibility of its industrial production.

Chemical Looping is an efficient and promising energy conversion technology that can achieve efficient and clean utilization of low-carbon alkanes by decoupling a chemical reaction into two or more independent reactions. In the chemical looping propane oxidative dehydrogenation (CL-ODHP) process, metal oxides (also known as oxygen carriers) are used as media to recycle and replenish the lattice oxygen of the oxygen carrier between the reduction bed and the oxidation bed, so that the oxygen removal and replenishment processes in the lattice can be effectively separated in space or time. Compared with direct dehydrogenation and oxidative dehydrogenation, chemical looping oxidative dehydrogenation technology has significant advantages such as lowering the reaction temperature, improving the selectivity of propylene, reducing the occurrence of side reactions, and avoiding product separation. The key to the application of this technology lies in the design and development of oxygen carriers, because oxygen carriers must simultaneously play multiple roles as catalysts (C-H bond activation) and reactants (lattice oxygen supply). At present, the oxygen carriers used for CL-ODH are mainly single-component metal oxides (vanadium oxide, chromium oxide, tungsten oxide, etc.), but it is difficult to achieve high activity and high selectivity to activate propane to propylene at the same time.

Summary of the invention

The present invention aims to solve the technical problems related to chemical chain low-carbon alkane dehydrogenation catalysts, and provides a vanadium-iron-based bimetallic oxide catalyst and a preparation method and application. The catalyst can couple the direct dehydrogenation site of propane and the selective hydrogen burning site at the nanoscale, wherein the _FeVO4 dispersed in a single layer on the surface of the carrier serves as the direct dehydrogenation catalytic site, and the bulk _FeVO4 nanoparticles serve as the hydrogen selective combustion site.

In order to solve the above technical problems, the present invention is implemented by the following technical solutions:

According to one aspect of the present invention, a vanadium-iron-based bimetallic oxide catalyst is provided, comprising a carrier, on which a monolayer dispersed FeVO ₄ is loaded, and the monolayer dispersed FeVO ₄ is loaded with bulk FeVO ₄ nanoparticles; the monolayer dispersed FeVO ₄ serves as a direct dehydrogenation catalytic site, and the FeVO ₄ nanoparticles serve as a hydrogen selective combustion site.

Furthermore, the carrier is Al ₂ O ₃ , SiO ₂ , TiO ₂ or molecular sieve.

Furthermore, the total mass of the _FeVO4 is 10-50wt.% of the total mass of the catalyst.

Furthermore, the total mass of the _FeVO4 is 30wt.% of the total mass of the catalyst.

According to another aspect of the present invention, a method for preparing the above-mentioned vanadium-iron-based bimetallic oxide catalyst is provided, which is carried out according to the following steps:

(1) dissolving and uniformly mixing an iron precursor salt and a vanadium precursor salt;

(2) impregnating the uniformly mixed salt solution obtained in step (1) onto the carrier and drying it;

(3) The impregnated carrier is calcined in an air atmosphere at a temperature of 500-600°C. The calcined catalyst is pressed into tablets, sieved and set aside.

Furthermore, in step (1), ferric nitrate is evenly dispersed in deionized water to form an impregnation solution-1, ammonium metavanadate and oxalic acid are mixed and evenly dissolved in deionized water to form an impregnation solution-2, and the impregnation solution-1 and the impregnation solution-2 are evenly mixed; wherein the mass ratio of ammonium metavanadate to oxalic acid is 1:2.

Furthermore, in step (2), the drying temperature is 80-100° C. and the drying time is 6-12 hours; in step (3), the roasting time is 1-8 hours; and the sieving mesh size is 20-40 mesh.

According to another aspect of the present invention, there is provided an application of the above-mentioned vanadium-iron-based bimetallic oxide catalyst in the chemical chain dehydrogenation of low-carbon alkanes. Under the condition of no oxygen co-feeding, the catalyst reacts with low-carbon alkanes, and the single-layer dispersed _FeVO4 acts as a direct dehydrogenation catalytic site to convert low-carbon alkanes into corresponding olefins and hydrogen; the _FeVO4 nanoparticles act as selective hydrogen combustion sites to selectively burn byproduct hydrogen to generate product water and release heat energy, and the _FeVO4 nanoparticles are reduced to a low-valent state; oxygen or air is introduced into the catalyst after the reaction for regeneration, and the lattice oxygen of the _FeVO4 nanoparticles is replenished, while the carbon deposits are burned and heat energy is released; after the above cycle, the catalyst returns to the initial state. .

Furthermore, the carbon number of the low carbon alkane is 2-4.

Furthermore, the catalyst and quartz sand are physically mixed evenly, and the mass ratio of the catalyst to the quartz sand is (0.2-1):1; the reaction is carried out under normal pressure, the reaction temperature is 450-650°C, nitrogen is pre-introduced to exclude air, and then propane is introduced; wherein the total flow rate of propane and nitrogen is 20-50 ml/min, and the volume percentage of propane is 5-30%.

The beneficial effects of the present invention are:

The vanadium-iron-based bimetallic oxide catalyst of the present invention is constructed with a dual catalytic site structure at the nanoscale, and organically couples propane dehydrogenation and selective hydrogen combustion at the nanoscale, effectively breaking the thermodynamic limitation; wherein, the _FeVO4 dispersed in a monolayer on the surface of the carrier is a catalytic site for the direct dehydrogenation of low-carbon alkanes, and the lattice oxygen in the bulk _FeVO4 nanoparticles participates in the selective combustion of hydrogen to generate product water; in addition, the vanadium-iron-based bimetallic oxide catalyst of the present invention can achieve that after the lattice oxygen of the bulk _FeVO4 nanoparticles is consumed, the _FeVO4 dispersed in a monolayer on the surface still participates in the direct dehydrogenation, and maintains a relatively high conversion rate and selectivity, thereby effectively solving the problem of sintering of pure iron oxide during the redox process.

The method for preparing the vanadium-iron-based bimetallic oxide catalyst of the present invention adopts an impregnation method, which is low in cost, simple to operate, and easy to scale up for production; meanwhile, cheap, easily available, and abundant iron oxide is used, which is non-toxic and environmentally friendly.

The vanadium-iron-based bimetallic oxide catalyst of the present invention is used in the chemical chain dehydrogenation of low-carbon alkanes, and has the outstanding advantages of high single-pass conversion rate of low-carbon alkanes and high selectivity of target product olefins; wherein by adjusting the carrier selection and loading amount, a catalyst with an optimal propylene yield can be obtained; at the same time, it can effectively solve the problem of sintering of pure iron oxide during the redox process, and achieve that after multiple reduction-oxidation regeneration cycles, its performance and structure can remain stable. The catalyst after the reaction is regenerated by oxygen or air, and the lattice oxygen of the low-valent iron vanadate nanoparticles is replenished, while the carbon deposits are effectively burned, and the generated heat is transferred through the catalyst medium. By adjusting the mass of the catalyst, a high degree of heat matching can be achieved. Compared with the prior art, the direct use of oxygen is avoided, the high cost of air separation is saved, and the formation of deep oxidation products is reduced and the safety hazards of mixing reducing and oxidizing gases are eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a chemical chain propane dehydrogenation process in the present invention;

FIG2 is a graph showing a propane conversion, propylene selectivity and b propylene yield of the catalysts prepared in Examples 1-4 during chemical chain propane dehydrogenation;

FIG3 is a graph showing the X-ray diffraction (XRD) test results of the catalysts prepared in Examples 1-4 of the present invention;

FIG4 is a graph showing the XRD test results of fresh catalysts obtained in Examples 5 and 6 of the present invention;

FIG5 is a spectrum of hydrogen temperature programmed reduction (H ₂ -TPR) test results of fresh catalysts prepared in Examples 1-4 of the present invention;

FIG6 is a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) image and an energy spectrum analysis surface scanning (EDS-MAPPING) image of the 30FeVO ₄ /Al ₂ O ₃ catalyst prepared in Example 1 of the present invention, showing the distribution of Al, O, Fe and V elements, respectively, wherein the scale of the HAADF-STEM image is 100 nm;

FIG. 7 is a graph showing the cycle stability test results of a reaction regeneration cycle using a 30FeVO ₄ /Al ₂ O ₃ catalyst in a chemical loop propane dehydrogenation process.

DETAILED DESCRIPTION

The present invention is further described in detail below through specific examples. The following examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

Embodiment 1:

Step 1, take 1.0 parts by mass of ferric nitrate and dissolve it evenly in 0.5 mL of deionized water to form an impregnation solution-1; mix 0.3 parts by mass of ammonium metavanadate and 0.6 parts by mass of oxalic acid and dissolve them evenly in 0.5 mL of deionized water to form an impregnation solution-2; and evenly mix the impregnation solution-1 and the impregnation solution-2.

Step 2: impregnate an equal volume of the impregnation solution obtained in step 1 onto 1.0 mass part of Al ₂ O ₃ carrier, and then dry at 80-100° C. for 6-12 hours.

Step 3, calcining the material obtained in step 2 in a muffle furnace, the calcination atmosphere is air, the calcination temperature is 500-600°C, to obtain a vanadium-iron-based bimetallic oxide catalyst supported on alumina, the mass percentage of _FeVO4 in the catalyst is 30% based on the mass of the carrier, and the molecular _formula is _30FeVO4 / _Al2O3 .

Step 4, the calcined catalyst is naturally cooled to room temperature, and then pressed into tablets and sieved to form a granular catalyst with a size of 20-40 mesh for standby use.

Step 5, loading the pressed Al ₂ O ₃ supported FeVO ₄ catalyst into a fixed bed reactor, introducing a reaction gas to carry out a reaction, wherein the reaction gas is propane and the balance gas is nitrogen.

Embodiment 2:

The preparation and reaction were carried out by the method of Example 1, except that in step 1, 0.26 parts by mass of ferric nitrate was uniformly dissolved in 0.5 mL of deionized water to form impregnation solution-1; 0.08 parts by mass of ammonium metavanadate and 0.16 parts by mass of oxalic acid were mixed and uniformly dissolved in 0.5 mL of deionized water to form impregnation solution-2. The mass percentage of FeVO ₄ in the obtained catalyst was 10% based on the mass of the carrier, and the molecular formula was recorded as 10FeVO ₄ /Al ₂ O ₃ .

Embodiment 3:

The preparation and reaction were carried out by the method of Example 1, except that in step 1, 2.4 parts by mass of ferric nitrate were uniformly dissolved in 0.5 mL of deionized water to form impregnation solution-1; 0.7 parts by mass of ammonium metavanadate and 1.5 parts by mass of oxalic acid were mixed and uniformly dissolved in 0.5 mL of deionized water to form impregnation solution-2. The mass percentage of FeVO ₄ in the obtained catalyst was 50% based on the mass of the carrier, and the molecular formula was recorded as 50FeVO ₄ /Al ₂ O ₃ .

Embodiment 4:

The method of Example 1 is used for preparation and reaction, the only difference is that in step 1, 5.0 parts by mass of ferric nitrate and 2.5 parts by mass of citric acid are mixed evenly and dissolved in 200.0 mL of deionized water to form solution-1; 1.5 parts by mass of ammonium metavanadate are evenly dissolved in 200.0 mL of deionized water to form solution-2; and the only difference is that in step 2, solution-2 is added to solution-1, stirred, and placed in a 100°C water bath for 3-4 hours, the solution is evaporated to dryness, and then dried at 80-100°C for 6-12 hours. The mass percentage of FeVO ₄ in the obtained catalyst is 100% based on the mass of the carrier, and the molecular formula is recorded as FeVO ₄ .

Embodiment 5:

The preparation and reaction were carried out in the same manner as in Example 1, except that the carrier in step 2 was changed to SiO ₂ . The mass percentage of FeVO ₄ in the obtained catalyst was 30% based on the mass of the carrier, and the molecular formula was recorded as 30FeVO ₄ /SiO ₂ .

Embodiment 6:

The preparation and reaction were carried out in the same manner as in Example 1, except that the carrier in step 2 was changed to TiO ₂ . The mass percentage of FeVO ₄ in the obtained catalyst was 30% based on the mass of the carrier, and the molecular formula was recorded as 30FeVO ₄ /TiO ₂ .

Embodiment 7:

The preparation and reaction were carried out in the same manner as in Example 1, except that the carrier in step 2 was changed to a molecular sieve. The mass percentage of FeVO ₄ in the obtained catalyst was 30% based on the mass of the carrier, and the molecular formula was recorded as 30FeVO ₄ /Zeolite.

Embodiment 8:

Step 1, 0.2-0.8 g of xFeVO ₄ /Al ₂ O ₃ (x=10, 30, 50, 100), 30FeVO ₄ /SiO ₂ , 30FeVO ₄ /TiO ₂ , and 30FeVO ₄ /Zeolite catalysts obtained in Examples 1-7 were weighed respectively and mixed with quartz sand (SiC). The experiment was carried out in a fixed bed tubular reactor at a reaction temperature of 450-600°C and a pressure of 1 atmosphere. Before the reaction, N ₂ was introduced to exhaust oxygen and air in the tubular reactor, and then propane was introduced, wherein the total flow rate of propane and nitrogen was 20 mL/min, and the volume fraction of propane was 10%. The product composition was detected by gas chromatography.

The propane conversion rate is calculated by the following formula:

in:

——Propane conversion rate, %

——Molar flow rate of propane at reactor inlet, moL/min

——Molar flow rate of propane at reactor outlet, moL/min

The product gas phase selectivity is calculated by the following formula:

in:

S Product A——Selectivity of gas phase product A, %

nProduct A——Product A output in gas phase, moL

∑nProduct——The sum of the amount of all product substances in the gas phase, moL

xProduct A——The content of gas phase product A in all gas phase products

The gas phase product A includes: C ₃ H ₆ , CO _x (carbon oxides, namely CO, CO ₂ ), CH ₄ , C ₂ H ₆ , and C ₂ H ₄ .

As shown in Figure 1, the chemical chaining low-carbon alkane oxidative dehydrogenation process uses metal oxides as a medium to recycle and replenish the lattice oxygen of the catalyst, which can effectively separate the oxygen removal and replenishment processes in the lattice in space or time. The catalyst after the reduction bed reaction is regenerated by introducing oxygen or air into the oxidation bed, and the lattice oxygen of the low-valent iron vanadate nanoparticles is replenished. At the same time, the carbon deposits are effectively burned, and the heat generated is transferred through the catalyst medium. By adjusting the mass of the catalyst, a high degree of heat matching can be achieved. The vanadium-iron-based bimetallic oxide catalyst of the present invention is applied to the chemical chaining dehydrogenation of low-carbon alkanes, and the carbon number of low-carbon alkanes is preferably 2-4. Taking the chemical chaining propane dehydrogenation reaction as an example, the physically mixed catalyst and quartz sand are filled in the reaction bed, nitrogen is pre-introduced to exclude air, and then propane is introduced; wherein the total flow rate of propane and nitrogen is 20-50ml/min, and the volume percentage of propane is 5-30%. Its performance at normal pressure and reaction temperature of 450-650℃ is investigated.

As shown in Figure 2, the bar graph shows the propane conversion rate, the solid dot graph represents the propylene selectivity, and the dotted triangle graph represents the CO ₂ selectivity. As can be seen from Figure 2, compared with the unloaded iron vanadate, the supported catalyst greatly improves the selectivity of propylene. Among them, 30FeVO ₄ /Al ₂ O ₃ can achieve a single-pass yield of propylene as high as 42%. The essential reason for its improved selectivity is that the supported catalyst realizes the organic combination of propane dehydrogenation catalytic sites and selective hydrogen combustion sites at the nanoscale, which can achieve a high conversion rate and selectivity of the catalyst after the lattice oxygen is consumed. It should be pointed out here that unloaded iron vanadate tends to over-oxidize propane.

The fresh catalyst prepared in the above examples was subjected to XRD test, and the results are shown in Figure 3. As can be seen from Figure 3, the unloaded iron vanadate catalyst has a triclinic structure and a P1 space group. When loaded on a carrier, 30FeVO ₄ /Al ₂ O ₃ and 50FeVO ₄ /Al ₂ O ₃ both exhibit XRD characteristic peaks similar to those of pure FeVO ₄ and γ-Al ₂ O ₃ , indicating that the crystal structure of the catalyst under higher loadings remains consistent with that of the unloaded catalyst. For 10FeVO ₄ /Al ₂ O ₃ , no XRD characteristic peaks similar to those of pure FeVO ₄ were observed, which may be due to the fact that the catalyst grains are smaller or highly dispersed on the carrier under this loading.

The present invention has found that the nanoscale tandem catalyst is also effective on other carrier-supported catalysts, as shown in FIG4 , and can be extended to SiO ₂ , TiO ₂ , molecular sieves, etc. as carriers.

The fresh catalyst prepared in the present invention was subjected to H ₂ -TPR test. The results are shown in FIG5. As the FeVO ₄ loading increases, the position of the reduction peak shifts significantly toward the low temperature direction, indicating that the activation ability of the catalyst for H ₂ is significantly enhanced. It should be mentioned here that if a catalyst with excellent hydrogen burning ability is effectively coupled with a catalytic site with dehydrogenation ability, it will be possible to achieve tandem catalysis of propane dehydrogenation and selective hydrogen combustion on a nanoscale.

From the performance test results, it can be seen that 30FeVO ₄ /Al ₂ O ₃ has the best performance, and its microstructure is further explored. Figure 6 shows the HAADF-STEM image and EDS-MAPPING image of the 30FeVO ₄ /Al ₂ O ₃ catalyst. It can be observed that the grain size of iron vanadate is about 80nm, which is a solid solution structure, which is consistent with the XRD results. The monolayer dispersed FeVO ₄ acts as a catalytic site for direct dehydrogenation of propane, and cooperates with adjacent iron vanadate grains to achieve tandem catalysis at the nanoscale.

Taking the best performing 30FeVO ₄ /Al ₂ O ₃ as an example, its cyclic stability in the chemical chain propane dehydrogenation reaction was explored, and the results are shown in Figure 7. It can be seen that after 10 cycles ("reaction-regeneration-reaction-regeneration" cycle), the catalyst performance remained basically unchanged. This shows that the supported vanadium-iron bimetallic oxide has good stability and can effectively solve the problem of sintering of pure iron oxide during the redox process, and has practical application prospects.

Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms of specific changes without departing from the scope of protection of the present invention and the claims, all of which fall within the scope of protection of the present invention.

Claims (7)

1. Application of a vanadium-iron-based bimetallic oxide catalyst in chemical chain dehydrogenation of light alkanes, characterized in that: The vanadium-iron-based bimetallic oxide catalyst comprises a carrier, wherein the carrier is one of Al ₂ O ₃ , SiO ₂ and TiO ₂ ; the carrier is loaded with a monolayer dispersed FeVO ₄ , and the monolayer dispersed FeVO ₄ is loaded with bulk FeVO ₄ nanoparticles; the monolayer dispersed FeVO ₄ serves as a direct dehydrogenation catalytic site, and the FeVO ₄ nanoparticles serve as a hydrogen selective combustion site; The vanadium-iron-based bimetallic oxide catalyst is prepared according to the following steps: (1) dissolving and uniformly mixing an iron precursor salt and a vanadium precursor salt; (2) impregnating the uniformly mixed salt solution obtained in step (1) onto the carrier and drying it; (3) calcining the impregnated carrier in an air atmosphere at a temperature of 500-600° C. The calcined catalyst is pressed into tablets, sieved and set aside; The vanadium-iron-based bimetallic oxide catalyst is used for chemical chain dehydrogenation of low-carbon alkanes: under the condition of no oxygen co-feeding, the catalyst reacts with low-carbon alkanes, the reaction is carried out at normal pressure, and the reaction temperature is 450-650°C; the monolayer dispersed _FeVO4 acts as a direct dehydrogenation catalytic site to convert low-carbon alkanes into corresponding olefins and hydrogen; the _FeVO4 nanoparticles act as selective hydrogen combustion sites to selectively burn byproduct hydrogen to generate product water and release heat energy, and the _FeVO4 nanoparticles are reduced to a low-valent state; oxygen or air is introduced into the catalyst after the reaction for regeneration, the lattice oxygen of the _FeVO4 nanoparticles is replenished, and the carbon deposits are burned and release heat energy; after the above cycle, the catalyst returns to its initial state. 2. The use of a vanadium-iron-based bimetallic oxide catalyst in the chemical chain dehydrogenation of light alkanes according to claim 1, characterized in that the total mass of the FeVO ₄ is 10-50wt.% of the total mass of the catalyst. 3. The use of a vanadium-iron-based bimetallic oxide catalyst in the chemical chain dehydrogenation of light alkanes according to claim 2, characterized in that the total mass of the FeVO ₄ is 30wt.% of the total mass of the catalyst. 4. Use of a vanadium-iron-based bimetallic oxide catalyst in chemical chain dehydrogenation of light alkanes according to claim 1, characterized in that the light alkanes have 2-4 carbon atoms. 5. The use of a vanadium-iron-based bimetallic oxide catalyst in the chemical chain dehydrogenation of light alkanes according to claim 1, characterized in that the catalyst and quartz sand are physically mixed evenly, and the mass ratio of the catalyst to the quartz sand is (0.2-1):1; nitrogen is pre-introduced to exclude air, and then propane is introduced; wherein the total flow rate of propane and nitrogen is 20-50 mL/min, and the volume percentage of propane is 5-30%. 6. The use of the vanadium-iron-based bimetallic oxide catalyst in the chemical chain dehydrogenation of light alkanes according to claim 1, characterized in that in step (1), ferric nitrate is uniformly dispersed in deionized water to form an impregnation solution-1, ammonium metavanadate and oxalic acid are mixed and uniformly dissolved in deionized water to form an impregnation solution-2, and the impregnation solution-1 and the impregnation solution-2 are uniformly mixed; wherein the mass ratio of ammonium metavanadate to oxalic acid is 1:2. 7. The use of the vanadium-iron-based bimetallic oxide catalyst in the chemical chain dehydrogenation of light alkanes according to claim 1, characterized in that in step (2), the drying temperature is 80-100°C and the drying time is 6-12h; in step (3), the roasting time is 1-8 hours; and the sieving mesh size is 20-40 mesh.