Defect-rich iridium dioxide nanomaterial and application thereof

Abstract

The application discloses a kind of rich defect iridium dioxide nanometer material and its application, the rich defect iridium dioxide nanometer material includes that iridium dioxide nanometer material and sulfur powder are mixed according to certain proportion, make it reach high uniform state;The mixed powder is poured into the alumina crucible of covering, then is transferred to the tube furnace of inert gas, calcination makes it fully react, using the high reducibility of sulfur powder at high temperature to iridium dioxide nanometer material is reduced and is handled, makes it part deoxidation and generates defect;Finally, the powder after calcination is taken out, carries out grinding treatment, namely obtains.The rich defect iridium dioxide nanometer material of the application introduces defect by the reduction treatment of sulfur powder at high temperature, makes its electrocatalytic activity and stability be significantly promoted, simultaneously by controlling calcination temperature and time, the overall microstructure of iridium dioxide nanometer material can be well retained, so that it has large specific surface area, is advantageous to give full play to its active advantage.

Description

Technical Field

[0001] This invention relates to the field of iridium dioxide nanomaterials technology, and more particularly to a defect-rich iridium dioxide nanomaterial and its applications. Background Technology

[0002] Iridium dioxide possesses numerous advantages, including excellent thermal stability, resistance to chemical and electrochemical corrosion, and high electrical conductivity, making it an ideal electrocatalyst material with broad application prospects in water electrolysis for hydrogen production and organic reactions. In water electrolysis environments based on acidic electrolytes, the conditions of high temperature, high pressure, and strong corrosion place extremely high demands on the catalyst. Furthermore, the anodic reaction involves strong electrochemical oxidation, requiring catalysts with excellent stability and electrochemical activity. Currently, the best-performing anodic electrocatalyst is based on iridium dioxide. However, many problems remain to be solved. For example, the activity of iridium dioxide compared to ruthenium dioxide still needs further improvement; its electrochemical stability remains poor at high potentials; and the extremely low reserves of iridium in the Earth's crust result in a still very high price for iridium dioxide.

[0003] Currently, iridium dioxide materials have broad application prospects in many catalytic reactions, but their inherent drawbacks greatly limit their application. For example, they exhibit poor activity, require further improvement in stability, and are expensive. Therefore, the convenient preparation of iridium dioxide nanomaterials with excellent electrocatalytic activity, stability, and low loading is of great significance. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, one of the objectives of this invention is to provide a defect-rich iridium dioxide nanomaterial that solves the aforementioned problems of traditional technology. Through the defect introduction strategy, its electrocatalytic activity and stability are significantly improved. At the same time, the high specific surface area of ​​the nanostructure is conducive to the improvement of its mass activity, which further reduces its loading and thus significantly reduces the application cost.

[0005] The second objective of this invention is to provide a method for applying the aforementioned defect-rich iridium dioxide nanomaterials in multiple catalytic fields, such as hydrogen production through water electrolysis and hydrogenation, dehydrogenation, and oxidation reactions of organic matter.

[0006] One of the objectives of this invention is achieved through the following technical solution:

[0007] A defect-rich iridium dioxide nanomaterial includes the following preparation steps:

[0008] S1: Mix commercial iridium dioxide nanomaterials and sulfur powder in a certain proportion to achieve a highly uniform state;

[0009] S2: Pour the above mixed powder into a covered alumina crucible, then transfer it to a tube furnace through which inert gas is introduced, and calcine it to allow it to react fully. Utilize the high reducing power of sulfur powder at high temperature to reduce the iridium dioxide nanomaterials, causing them to partially deoxidize and generate defects.

[0010] S3: Finally, the calcined powder is taken out and subjected to simple grinding to obtain the final product.

[0011] Further, in step S1, the mass ratio of iridium dioxide nanomaterials to sulfur powder is 1:0.1-1:10, such as 1:0.1, 1:0.5, 1:0.8, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10.

[0012] Furthermore, in step S2, the calcination time is 0.5h-5h (e.g., 0.5h, 0.8h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h), and the calcination temperature is controlled between 450℃-650℃ (e.g., 450℃, 480℃, 500℃, 550℃, 580℃, 600℃, 650℃).

[0013] Furthermore, the inert gas is one or more of helium, neon, argon, krypton, xenon, and radon.

[0014] The second objective of this invention is achieved by the following technical solution:

[0015] One application is to utilize the aforementioned defect-rich iridium dioxide nanomaterials in multiple catalytic fields, such as hydrogen production through water electrolysis and hydrogenation, dehydrogenation, and oxidation reactions of organic matter.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. The defect-rich iridium dioxide nanomaterial of the present invention introduces defects through the reduction treatment of sulfur powder at high temperature, which significantly improves its electrocatalytic activity and stability. At the same time, by controlling the calcination temperature and time, the overall microstructure of the iridium dioxide nanomaterial can be well preserved, giving it a large specific surface area, which is conducive to giving full play to its activity advantages.

[0018] 2. The defect-rich iridium dioxide material of the present invention is nanoscale and has a certain degree of surface defects, excellent electrocatalytic activity and stability.

[0019] 3. The preparation method of the defect-rich iridium dioxide nanomaterial of the present invention is simple and effective, requires no complicated equipment, can quickly achieve defect control, and can be extended to other material systems. Attached Figure Description

[0020] Figure 1 TEM image of original commercial IrO2 nanomaterials;

[0021] Figure 2 TEM image of the IrO2 nanomaterials prepared in Example 1;

[0022] Figure 3 TEM image of the IrO2 nanomaterials prepared in Example 2;

[0023] Figure 4 TEM image of the IrO2 nanomaterials prepared in Example 3;

[0024] Figure 5 XPS (O 1s) spectra of IrO2 prepared in Example 3 and the original IrO2 nanomaterial;

[0025] Figure 6 Electrocatalytic oxygen evolution performance of IrO2 prepared in Example 3 and original IrO2 nanomaterial, where a. LSV curve, b. CP curve. Detailed Implementation

[0026] The present invention will now be further described in conjunction with specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. Unless otherwise specified, all reagents or instruments used are commercially available conventional products.

[0027] Unless otherwise specified, all reagents used in the examples are commercially available.

[0028] Example 1

[0029] Weigh out commercial iridium dioxide nanoparticles (such as...) Figure 1 The mixture (as shown) and sulfur powder (mass ratio 1:0.1) were poured into a mortar and ground thoroughly to ensure uniform mixing. The powder mixture was then poured into an alumina crucible, covered, and transferred to a tube furnace. Argon gas was introduced to isolate the material from oxygen. The tube furnace was then heated to 450℃ and calcined for 5 hours. After the reaction was complete, the material was cooled with the furnace. Finally, the calcined powder was poured into a mortar and simply ground to obtain iridium dioxide nanoparticles with a certain defect content, the microstructure of which is shown in the figure. Figure 2 As shown.

[0030] from Figure 2As can be seen, the original commercial iridium dioxide nanopowder has a complete crystal lattice and no obvious defect areas on the surface; however, after sulfur reduction treatment, a disordered layer with a thickness of 1-2 nm appeared on the surface, and some disordered areas also appeared on the surface, indicating that sulfur reduction treatment introduced a certain amount of defects on the surface of iridium dioxide nanopowder.

[0031] Example 2

[0032] Commercial iridium dioxide nanoparticles and sulfur powder (mass ratio 1:10) were weighed and thoroughly ground in a mortar until homogeneous. The mixture was then poured into an alumina crucible, covered, and transferred to a tube furnace, where argon gas was introduced to isolate the material from oxygen. The tube furnace was then heated to 650℃ and calcined for 0.5 hours. After the reaction was complete, the material was cooled with the furnace. Finally, the calcined powder was poured into a mortar and simply ground to obtain iridium dioxide nanoparticles with a certain defect content, the microstructure of which is shown below. Figure 3 As shown.

[0033] from Figure 3 As can be seen, a certain thickness of disordered amorphous layer appeared on the surface after sulfur reduction treatment, and there were also some disordered areas on the surface, indicating that sulfur reduction treatment introduced a certain amount of defects on the surface of iridium dioxide nanopowder.

[0034] Example 3

[0035] Commercial iridium dioxide nanoparticles and sulfur powder (mass ratio 1:5) were weighed and thoroughly ground in a mortar until homogeneous. The mixture was then poured into an alumina crucible, covered, and transferred to a tube furnace, where argon gas was introduced to isolate the material from oxygen. The tube furnace was then heated to 550℃ and calcined for 2.5 hours. After the reaction was complete, the material was cooled with the furnace. Finally, the calcined powder was poured into a mortar and simply ground to obtain iridium dioxide nanoparticles with a certain defect content, the microstructure of which is shown below. Figure 4 As shown.

[0036] from Figure 4 As can be seen, a certain thickness of disordered amorphous layer appeared on the surface after sulfur reduction treatment, and there were also some disordered areas on the surface, indicating that sulfur reduction treatment introduced a certain amount of defects on the surface of iridium dioxide nanopowder.

[0037] Performance testing:

[0038] 1. Defect state testing of iridium dioxide nanopowder

[0039] The TEM results from the three examples above show that a certain amount of defect areas exist on the surface of the iridium dioxide nanopowder after sulfur reduction treatment. We further used X-ray photoelectron spectroscopy to test the defect state of the original and Example 3 iridium dioxide nanopowders. The test results are as follows: Figure 5 and Figure 6 .

[0040] from Figure 5 It can be seen that the peak intensity corresponding to oxygen defects in the O 1s spectrum significantly increased after sulfur reduction treatment, which also indicates a significant increase in oxygen defect content. Furthermore, we characterized the effect of defect introduction on the electrocatalytic performance of iridium dioxide nanoparticles.

[0041] 2. Electrocatalytic oxygen evolution performance test

[0042] Figure 6 The electrocatalytic oxygen evolution performance of the iridium dioxide nanoparticles in the original and Example 3 in 0.5M H2SO4 solution is shown.

[0043] As can be seen from the LSV curve in Figure a, the overpotential is significantly reduced after sulfur reduction treatment, indicating that its electrocatalytic activity has been improved.

[0044] As can be seen from the CP curve in Figure b, the potential of the original iridium dioxide increased significantly after about 4 hours, indicating its poor stability. However, the voltage of the sulfur-reduced iridium dioxide remained almost unchanged after 25 hours of continuous testing, indicating its excellent stability.

[0045] In summary, from Figure 6 The results show that the electrocatalytic oxygen evolution activity and stability of iridium dioxide nanoparticles after sulfur reduction treatment are significantly improved.

[0046] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A defect-rich iridium dioxide nanomaterial, characterized in that, The preparation steps include: S1: fully mix the iridium dioxide nanomaterial and sulfur powder in a certain proportion to achieve a high uniform state; S2: pour the mixed powder into an alumina crucible with a cover, then transfer to a tube furnace with inert gas, calcine to fully react, use the high reducibility of sulfur powder at high temperature to reduce the iridium dioxide nanomaterial, and make it partially deoxidize to generate defects; S3: finally take out the calcined powder, grind it, and obtain it.

2. The defect-rich iridium dioxide nanomaterial of claim 1, wherein, In step S1, the mass ratio of iridium dioxide nanomaterial to sulfur powder is 1:0.1-1:

10.

3. The defect-rich iridium dioxide nanomaterial of claim 1, wherein, In step S2, the calcination time is 0.5h-5h, and the calcination temperature is controlled at 450℃-650℃.

4. An application according to claim 1, characterized in that The application of the defect-rich iridium dioxide nanomaterial as claimed in any one of claims 1-3 in the field of catalysis of water electrolysis for hydrogen production and organic hydrogenation, dehydrogenation, and oxidation reactions.

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