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CN-121988324-A - Carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst and preparation method and application thereof

CN121988324ACN 121988324 ACN121988324 ACN 121988324ACN-121988324-A

Abstract

The invention discloses a carbon/titanium oxide nanowire/ferroferric oxide composite material, a preparation method and application thereof, the method prepares a precursor by graphite, titanium dioxide, ferric nitrate and sodium hydroxide, and the precursor is calcined at a high temperature to obtain the catalyst. The catalyst prepared by the invention can realize the photo-thermal degradation of polyolefin at 300 ℃ under the irradiation of the simulated sunlight of a xenon lamp in the air atmosphere, and the yield of photo-thermal degradation liquid hydrocarbon can reach 89%, so that the C-C bond rupture in the polyolefin can be effectively promoted, and the generation of gaseous hydrocarbon products is avoided. The catalyst prepared by the invention can be expanded to the photo-thermal degradation of commercial waste polyethylene plastics. Compared with the prior photo-thermal degradation method, the catalyst has stable performance and high catalytic activity, can bear the high temperature condition of photo-thermal degradation at least and can be repeatedly used for 5 times.

Inventors

  • LU GUOPING
  • WANG YOUQING
  • ZHANG XUEPING

Assignees

  • 南京理工大学

Dates

Publication Date
20260508
Application Date
20260327

Claims (10)

  1. 1. The preparation method of the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst is characterized by comprising the following steps: dispersing titanium dioxide powder into sodium hydroxide solution to obtain a first mixture, wherein the mass ratio of the titanium dioxide to the sodium hydroxide is 20:1; step two, carrying out hydrothermal reaction on the first mixture obtained in the step one at a certain rotating speed and temperature to obtain a second mixture; step three, the second mixture obtained in the step two is subjected to post-treatment to obtain titanium oxide nanowires; Uniformly mixing the titanium oxide nanowire obtained in the step three, fe (NO 3 ) 3 ·9H 2 O and graphite), and performing ball milling to obtain a precursor; And fifthly, calcining the precursor obtained in the step four to obtain the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst.
  2. 2. The method for preparing a carbon/titanium oxide nanowire/ferroferric oxide composite catalyst according to claim 1, wherein the molar concentration of the sodium hydroxide solution in the first step is 10M.
  3. 3. The method for preparing a carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst according to claim 1, wherein the rotating speed in the second step is 450 r/min, the temperature is 130 ℃, and the hydrothermal reaction time is 24 hours.
  4. 4. The method for preparing the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst according to claim 1, wherein the post-treatment in the step three is specifically that solid products are collected through centrifugation, washed twice with hydrochloric acid aqueous solution to replace Na + , washed to be neutral with deionized water and dried, wherein the molar concentration of the hydrochloric acid aqueous solution is 1M.
  5. 5. The method for preparing the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst according to claim 1, wherein in the fourth step, the mass ratio of the titanium oxide nanowire to Fe (NO 3 ) 3 ·9H 2 O to graphite) is 4:16:5, the rotation speed of ball milling is 250 r/min, and the ball milling time is 3h.
  6. 6. The preparation method of the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst according to claim 1, wherein in the fifth step, the calcination is specifically carried out in the presence of N 2 at a temperature rising rate of 5 ℃ per minute to 800-1000 ℃ for 1-3 hours.
  7. 7. A carbon/titanium oxide nanowire/ferroferric oxide composite catalyst, characterized in that it is prepared by the preparation method of the carbon/titanium oxide nanowire/ferroferric oxide composite catalyst according to any one of claims 1 to 6.
  8. 8. Use of the carbon/titanium oxide nanowire/ferroferric oxide composite catalyst according to claim 7 in a polyolefin photo-thermal degradation reaction.
  9. 9. The application of the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst in the photo-thermal degradation reaction of polyolefin, which is disclosed by claim 8, is characterized by comprising the steps of placing polyolefin and the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst in a reactor, uniformly mixing, carrying out simulated sunlight irradiation by a xenon lamp, carrying out the photo-thermal degradation reaction at 280-360 ℃ for 60-240 min, separating the catalyst and photo-thermal degradation products after the reaction is finished, and recycling the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst.
  10. 10. The application of the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst in the polyolefin photo-thermal degradation reaction, according to claim 9, wherein the mass ratio of the polyolefin to the carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst is 1-6:1.

Description

Carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst and preparation method and application thereof Technical Field The invention belongs to the technical field of plastic degradation, and particularly relates to a carbon/titanium oxide nanowire/ferroferric oxide composite material catalyst, and a preparation method and application thereof. Background The proliferation of global plastic waste has become one of the most urgent environmental crisis in the 21 st century. The global plastic production in 2021 has reached about 3.907 million tons, which is expected to be more than 5 hundred million tons per year by 2050. Polyethylene is used in polyolefin in a proportion far exceeding that of other types due to its mechanical durability and chemical stability, and the annual yield exceeds 1 million tons. However, this high inertness also results in its persistence in the environment, degradation times of up to several hundred years. At present, the global plastic recovery rate is still at an extremely low level, only 9-10% of plastic waste is recycled, and the rest is burnt or accumulated in landfill sites and natural ecosystems. The efficient recovery of polyethylene waste is not only important to reduce environmental pollution, but also is beneficial to recovery of valuable hydrocarbon resources and promotion of implementation of the recycling economy principle. Unfortunately, conventional recovery methods have not achieved this goal in an cost-effective and environmentally sustainable manner. Conventional plastic recycling techniques are generally classified into mechanical recycling and chemical recycling. Although mechanical recycling has been widely used, it is problematic in that material properties are degraded due to chain breakage and contamination, and it is difficult to adapt to various waste streams. In contrast, chemical recovery (including pyrolysis, hydrogenolysis, and photodegradation) aims to depolymerize plastics into fuels or monomers. Among them, pyrolysis technology is most mature, but generally requires high temperature (400-700 ℃) and long reaction time, and often has the problems of poor selectivity and high energy consumption. Photocatalysis is often limited by problems such as insufficient light absorption and photo-generated carrier recombination. Therefore, it is desirable to construct a synergistic platform that integrates light energy and heat energy to drive efficient selective plastic depolymerization. Photo-thermal catalysis effectively fuses the photo-catalytic and thermal catalytic technologies by converting broad spectrum photons into localized heat (and in some cases generating hot carriers). Unlike pyrolysis, photothermal processes are capable of precisely directing heat to the active sites of the catalyst. This localized heating effect lowers the activation energy barrier of the reaction, allowing the reaction to proceed at a relatively low temperature with an acceleration and facilitating the realization of a solar driven mode of operation. In contrast, traditional photocatalysis relies mainly on ultraviolet light and part of visible light, i.e. light radiation with photon energy higher than the semiconductor band gap, which method is completely incapable of utilizing infrared light accounting for about 50% of solar energy. Although infrared photons cannot directly excite electron transitions, they can be efficiently absorbed by certain materials (particularly materials with defects or plasma characteristics) and converted into heat energy, while photothermal catalysis breaks through the fundamental limitation of pure photocatalytic technology by introducing a thermal effect component, thereby significantly improving the reaction rate and the overall energy utilization efficiency. Recent studies confirm the feasibility and versatility of the photo-thermal recovery plastic technology. The use of Ru/TiO 2 nanocrystals to photo-thermally hydrogenolyze polyolefins in simulated sunlight has been reported to successfully convert them to liquid hydrocarbons and waxy products without the addition of solvents, however, the hydrogenolysis reaction using ruthenium-based catalysts can degrade polyethylene to liquid alkanes at milder conditions, but its dependence on hydrogen, high pressure conditions and noble metals limits the scale applications. The two-dimensional silicon stack structure of the coated copper nanoparticles also demonstrates efficient photo-thermal degradation of the polyolefin by utilizing strong light absorption and nanoscale thermal localization effects. However, the prior art generally relies on noble metal catalysts and the synthesis steps are complex, so that there is a great need for an alternative strategy for photo-thermal polymerization recovery of polyethylene based on inexpensive non-noble metals with simple preparation process and mild catalytic reaction conditions, which would represent a significant advantage in terms of cost a