CN112121839A

CN112121839A - Copper-oxygen co-doped carbon-nitrogen catalyst and preparation method and application thereof

Info

Publication number: CN112121839A
Application number: CN202011056482.4A
Authority: CN
Inventors: 李东亚; 夏东升; 关泽宇; 徐海明; 宋辉; 左诗语
Original assignee: Wuhan Textile University
Current assignee: Wuhan Textile University
Priority date: 2020-09-29
Filing date: 2020-09-29
Publication date: 2020-12-25
Anticipated expiration: 2040-09-29
Also published as: CN112121839B

Abstract

The invention specifically relates to a copper-oxygen co-doped carbon-nitrogen catalyst, and a preparation method and application thereof, belongs to the field of catalysts, and the copper-oxygen co-doped carbon-nitrogen catalyst provided by the embodiment of the invention takes copper acetylacetonate and bis (8-hydroxyquinoline) copper (II) as precursors of Cu and O to dope g-C₃N₄Cu and O with g-C in copper acetylacetonate and bis (8-quinolinolato) copper (II)₃N₄And (3) mixing and pyrolyzing to enable O to replace 2 coordinated N sites and stabilize metal Cu atoms to form an electron-rich region to effectively catalyze persulfate, so that the copper-oxygen co-doped carbon-nitrogen catalyst with excellent catalytic performance and stability is obtained.

Description

Copper-oxygen co-doped carbon-nitrogen catalyst and preparation method and application thereof

Technical Field

The invention belongs to the field of catalysts, and particularly relates to a copper-oxygen co-doped carbon-nitrogen catalyst, and a preparation method and application thereof.

Background

With the increasing discharge of more and more toxic organic pollutants into water, the toxic organic pollutants have extremely low threshold values, strong toxicological effects and ecological hazards, and seriously threaten the health and environmental safety of human beings. In particular, the treatment of toxic organic pollutants such as Bisphenol a (BPA) in water bodies, such as micro-plastics, is receiving increasing attention and poses a serious challenge to the existing water treatment technology.

The Fenton-like process, which is considered as a clean and efficient method for generating reactive oxygen-containing radicals to eliminate persistent organic pollutants, is a promising strategy to cope with growing environmental pollution and shortage of fresh water resources, and the Fenton-like system based on sulfate radicals is receiving increasing attention to the degradation of persistent pollutants in water by activating Peroxymonosulfate (PDS). Various transition metal-based materials have been studied as Fenton-like catalysts for PMS activation, however, at present, transition metal-based materials suffer from metal ion leaching and low catalytic performance.

Disclosure of Invention

In view of the above problems, the present invention is proposed to provide a copper oxygen co-doped carbon nitrogen catalyst, a preparation method and an application thereof, which overcome the above problems or at least partially solve the above problems.

The embodiment of the invention provides a preparation method of a copper-oxygen co-doped carbon-nitrogen catalyst, which comprises the following steps:

heating triazine nitrogen-containing heterocyclic organic compound to 400-600 ℃ at the speed of 1-10K/min and preserving the heat for 1-4h to prepare g-C₃N₄；

Copper acetylacetonate and said g-C₃N₄Mixing and grinding to obtain a first mixture;

heating the first mixture to 400-600 ℃ at the speed of 1-10K/min in an oxygen-free environment and preserving heat for 1-4h to obtain a first reactant;

soaking the first reactant in an acid medium, and stirring for 1-6h at the temperature of 30-100 ℃ to obtain a second reactant;

and washing the second reactant to be neutral, and drying to obtain the copper-oxygen co-doped carbon-nitrogen catalyst.

Optionally, the triazine nitrogen-containing heterocyclic organic compound is heated to 400-600 ℃ at the rate of 1-10K/min and is kept warm for 1-4h to prepare g-C₃N₄The method comprises the following steps:

heating triazine nitrogen-containing heterocyclic organic compound to 550 ℃ at the speed of 5K/min and preserving heat for 4 hours to prepare g-C₃N₄。

Optionally, the copper acetylacetonate and the g-C₃N₄According to the mass ratio of 1: 1-20.

Optionally, the first mixture is heated to 400-:

heating the first mixture to 550 ℃ at the speed of 5K/min in an oxygen-free environment, and keeping the temperature for 4 hours to obtain a first reactant;

soaking the first reactant in an acidic medium, and stirring at the temperature of 30-100 ℃ for 1-6h to obtain a second reactant, wherein the second reactant comprises:

the first reactant was immersed in an acidic medium and stirred at a temperature of 70 ℃ for 4h to obtain a second reactant.

Optionally, the copper acetylacetonate and the g-C₃N₄Mixing and grinding to obtain a first mixture comprising:

bis (8-hydroxyquinoline) copper (II) and the g-C₃N₄Mixing and grinding to obtain a first mixture;

heating the first mixture to 400-600 ℃ at the rate of 1-10K/min in an oxygen-free environment and preserving the temperature for 1-4h to obtain a first reactant, wherein the first reactant comprises:

under the inert gas atmosphere, heating the first mixture to 400-600 ℃ at the speed of 5-10K/min and preserving the heat for 2-4h to obtain a first reactant;

washing the second reactant to be neutral, and drying to obtain the copper-oxygen co-doped carbon-nitrogen catalyst, which comprises the following steps:

and washing the second reactant to be neutral, drying, heating to 400-600 ℃ at the speed of 5-10K/min in the atmosphere of inert gas, and preserving heat for 2-4h to obtain the copper-oxygen co-doped carbon nitrogen catalyst.

Optionally, said bis (8-quinolinolato) copper (II) and said g-C₃N₄According to the mass ratio of 1: 1-15.

Optionally, the first mixture is heated to 400-600 ℃ at a rate of 5-10K/min and is kept at the temperature for 2-4h under an inert gas atmosphere to obtain a first reactant, which comprises:

heating the first mixture to 550 ℃ at the rate of 5K/min under the inert gas atmosphere, and keeping the temperature for 4 hours to obtain a first reactant;

and washing the second reactant to be neutral, drying, heating to 400-600 ℃ at the speed of 5-10K/min in the atmosphere of inert gas, and preserving heat for 2-4h to obtain the copper-oxygen co-doped carbon-nitrogen catalyst, wherein the method comprises the following steps:

and washing the second reactant to be neutral, drying, heating to 550 ℃ at the speed of 5K/min in the atmosphere of inert gas, and preserving heat for 4h to obtain the copper-oxygen co-doped carbon nitrogen catalyst.

Optionally, the acidic medium is H₂SO₄、HNO₃And HCl, and the molar concentration of the acidic medium is 0.1-10 mol/L.

Based on the same inventive concept, the embodiment of the invention also provides a copper-oxygen co-doped carbon-nitrogen catalyst prepared by the preparation method.

Based on the same inventive concept, the embodiment of the invention also provides an application of the copper-oxygen co-doped carbon-nitrogen catalyst, and the copper-oxygen co-doped carbon-nitrogen catalyst is used for catalytic oxidation of organic pollutants.

One or more embodiments of the present invention have at least the following technical effects or advantages:

the copper-oxygen co-doped carbon-nitrogen catalyst provided by the embodiment of the invention takes copper acetylacetonate and bis (8-hydroxyquinoline) copper (II) as precursors of Cu and O to dope g-C₃N₄Cu and O with g-C in copper acetylacetonate and bis (8-quinolinolato) copper (II)₃N₄And (3) mixing and pyrolyzing to enable O to replace 2 coordinated N sites and stabilize metal Cu atoms to form an electron-rich region to effectively catalyze persulfate, so that the copper-oxygen co-doped carbon-nitrogen catalyst with excellent catalytic performance and stability is obtained.

Copper acetylacetonate and bis (8-hydroxyquinoline) copper (II) are used for respectively preparing two copper oxygen co-doped carbon nitrogen catalysts of SA and SB, SA is used for catalyzing peroxymonosulfate PDS and hypermonosulfate PMS, SB is used for catalyzing hypermonosulfate PMS, wherein SA has pH adaptability of 3-9, SB has pH adaptability of 3-9, and all have excellent stability.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 shows the doping amounts (Cu source/g-C) of different Cu sources (Cu acetylacetonate) in example 1 of the present invention₃N₄Mass ratio of (d);

FIG. 2 shows the doping amounts (Cu source/g-C) of different Cu sources (bis (8-quinolinolato) Cu (II)) in example 4 of the present invention₃N₄Mass ratio of (d);

FIG. 3 is an XPS-Ols spectrum of a copper oxygen co-doped carbon nitrogen catalyst (SA) prepared in example 1 of the present invention;

FIG. 4 is an XPS-Ols spectrum of a copper oxygen co-doped carbon nitrogen catalyst (SB) prepared in example 4 of the present invention;

FIG. 5 is a graph showing that the copper-oxygen co-doped carbon-nitrogen catalyst (SA) prepared in example 1 of the present invention catalyzes PDS to degrade BPA in different systems;

FIG. 6 is a graph showing that the copper-oxygen co-doped carbon-nitrogen catalyst (SA) prepared in example 1 of the present invention catalyzes PMS to degrade BPA in different systems;

FIG. 7 is a graph of experimental data of radical trapping in PMS to degrade BPA with copper-oxygen co-doped carbon-nitrogen catalyst (SB) prepared in example 4 of the present invention; indicating that the degradation of the contaminant BPA may proceed via a non-radical reaction pathway;

FIG. 8 is a graph showing the cyclic activity of the Cu/O co-doped C/N catalyst (SA) prepared in example 1 of the present invention;

FIG. 9 is a graph showing the cycle activity of the Cu/O co-doped C/N catalyst (SB) prepared in example 4 of the present invention;

FIG. 10 shows the results of experiments on the inhibition of radicals in BPA degradation by SA/PDS systems comprising SA and PDS according to example 1 of the present invention;

FIG. 11 shows the results of experiments on the inhibition of radicals in BPA degradation by SA/PMS system comprising SA and PMS obtained in example 1 of the present invention;

FIG. 12 shows the results of experiments on the free radical inhibition of BPA degradation by a SB/PMS system composed of SB and PMS according to example 4 of the present invention;

FIG. 13 shows N of SA obtained in example 1 of the present invention₂The adsorption-desorption isotherms show typical type IV isotherms;

FIG. 14 shows the N of SB obtained in example 4 of the present invention₂The adsorption-desorption isotherms show typical type IV isotherms;

FIG. 15 is an XPS survey of SA according to example 1 of the present invention;

FIG. 16 is an XPS survey of SB prepared in example 4 of the present invention;

FIG. 17 shows the resistance results for SA prepared in example 1 of the present invention;

FIG. 18 shows the results of resistance of SB obtained in example 4 of the present invention;

FIG. 19 shows the degradation of SA obtained in example 1 of the present invention;

FIG. 20 shows the degradation of SB obtained in example 4 of the present invention;

FIG. 21 SA catalyzes degradation of PDS for BPA over a pH range of 3-9;

FIG. 22 SB catalyzes degradation of PMS for BPA over a pH range of 3-9;

FIG. 23 is g-C₃N₄Scanning electron micrographs of SA and SB;

FIG. 24 shows the electron paramagnetic resonance experiment using tetramethylpiperidinol to capture singlet oxygen in SA + PMS system;

FIG. 25 is a graph showing the electron paramagnetic resonance experiment using tetramethylpiperidinol to capture singlet oxygen in SA + PDS system;

FIG. 26 shows the electron paramagnetic resonance experiment using tetramethylpiperidinol to capture singlet oxygen in the SB + PMS system;

FIG. 27 is an electron microscopy mapping of SA material;

FIG. 28 is an electron microscopy mapping of SB material;

FIG. 29 is a Fourier transform infrared spectrum of SB material;

FIG. 30 is an electron microscopy mapping of SA material;

FIG. 31 is a linear sweep voltammogram of the SA material;

FIG. 32 is a linear scanning voltammogram of the SB material;

FIG. 33 is a graph showing degradation of different contaminants of the SA material;

FIG. 34 is a graph showing the degradation of different contaminants of SB materials.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.

Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

It should be further noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

In order to solve the above technical problems, embodiments in the embodiments of the present invention have the following general ideas:

the invention provides a preparation method of a copper-oxygen co-doped carbon-nitrogen catalyst, which comprises the following steps:

At a temperature of 400 ℃ and 600 ℃, a pure phase g-C can be formed₃N₄And decomposing the copper-containing oxygen compound at the temperature for recombination, and washing away the surface Cu simple substance by a certain concentration of acid medium at high temperature.

The temperature is too high or too low, which can cause the material to be burnt out or impure, and the concentration and the temperature of the acid medium can wash out unstable copper on the surface without damaging the basic structure of the material.

In this embodiment, the drying temperature is 40 to 100 ℃ and the drying time is 3 to 10 hours.

As some optional embodiments, the triazine nitrogen-containing heterocyclic organic compound is heated to 400-600 ℃ at the speed of 1-10K/min and is kept for 1-4h to prepare g-C₃N₄The method comprises the following steps:

adding triazine nitrogen-containing heterocyclic organic compound at the rate of 5K/minHeating to 550 deg.C and maintaining for 4h to obtain g-C₃N₄。

As some alternative embodiments, the copper acetylacetonate and the g-C₃N₄According to the mass ratio of 1: 1-20.

As some optional embodiments, the heating the first mixture to 400-:

As some alternative embodiments, the copper acetylacetonate and the g-C are₃N₄Mixing and grinding to obtain a first mixture comprising:

As some alternative embodiments, the bis (8-quinolinolato) copper (II) and the g-C₃N₄According to the mass ratio of 1: 1-15.

As some optional embodiments, the heating the first mixture to 400-:

As some alternative embodiments, the acidic medium is H₂SO₄、HNO₃And HCl, and the molar concentration of the acidic medium is 0.1-10 mol/L.

Based on the same inventive concept, the embodiment also provides a copper-oxygen co-doped carbon-nitrogen catalyst prepared by the preparation method.

Based on the same inventive concept, the embodiment also provides an application of the copper oxygen co-doped carbon nitrogen catalyst, and the copper oxygen co-doped carbon nitrogen catalyst is used for catalytic oxidation of organic pollutants.

In this embodiment, when the copper-oxygen co-doped carbon-nitrogen catalyst is used for catalytic oxidation of organic pollutants, the oxidant includes, but is not limited to, at least one of the following: potassium hydrogen persulfate, potassium peroxysulfate;

organic contaminants include, but are not limited to, at least one of: bisphenol A, diclofenac sodium and rhodamine B.

The sludge-based biochar, the sludge-based composite catalyst, and the preparation methods and applications thereof provided by the embodiments of the present invention will be described in detail below with reference to the examples and experimental data.

Example 1

The preparation method of the copper-oxygen co-doped carbon-nitrogen catalyst provided by the invention comprises the following steps:

heating triazine nitrogen-containing heterocyclic organic compound to 550 ℃ at the speed of 5K/min and preserving heat for 4 hours to prepare g-C₃N₄；

Copper acetylacetonate and said g-C₃N₄Mixing and grinding the materials in a mass ratio of 1:10 to obtain a first mixture;

soaking the first reactant in 1mol/L H₂SO₄Stirring for 4h at 70 ℃ in an acidic medium to obtain a second reactant;

and washing the second reactant to be neutral, and drying at the temperature of 70 ℃ for 6h to obtain the copper-oxygen co-doped carbon-nitrogen catalyst.

Example 2

heating triazine nitrogen-containing heterocyclic organic compound to 600 ℃ at the speed of 1K/min and preserving heat for 1h to prepare g-C₃N₄；

Copper acetylacetonate and said g-C₃N₄Mixing and grinding the materials in a mass ratio of 1:20 to obtain a first mixture;

heating the first mixture to 400 ℃ at the rate of 1K/min in an oxygen-free environment, and keeping the temperature for 1h to obtain a first reactant;

soaking the first reactant in 1mol/L H₂SO₄Stirring for 1h in an acidic medium at the temperature of 30 ℃ to obtain a second reactant;

and washing the second reactant to be neutral, and drying at the temperature of 40 ℃ for 3h to obtain the copper-oxygen co-doped carbon-nitrogen catalyst.

Example 3

heating triazine nitrogen-containing heterocyclic organic compound to 400 ℃ at the speed of 10K/min and preserving heat for 4h to prepare g-C₃N₄；

Copper acetylacetonate and said g-C₃N₄Mixing and grinding the materials in a mass ratio of 1:1 to obtain a first mixture;

heating the first mixture to 600 ℃ at a speed of 10K/min in an oxygen-free environment, and keeping the temperature for 4 hours to obtain a first reactant;

soaking the first reactant in 1mol/L H₂SO₄Stirring for 6h at 100 ℃ in an acidic medium to obtain a second reactant;

and washing the second reactant to be neutral, and drying at the temperature of 100 ℃ for 10h to obtain the copper-oxygen co-doped carbon-nitrogen catalyst.

Example 4

Bis (8-hydroxyquinoline) copper (II) and the g-C₃N₄Mixing and grinding according to the mass ratio of 1:5 to obtain a first mixture;

soaking the first reactant in 0.5mol/L H₂SO₄And 0.5mol/LHNO₃Stirring the mixture for 4 hours at the temperature of 70 ℃ in the composed acidic medium to obtain a second reactant;

and washing the second reactant to be neutral, drying the second reactant at the temperature of 70 ℃ for 7h, heating the second reactant to 550 ℃ at the speed of 5K/min in an inert gas atmosphere after drying, and keeping the temperature for 4h to obtain the copper-oxygen co-doped carbon nitrogen catalyst.

Example 5

Bis (8-hydroxyquinoline) copper (II)And said g-C₃N₄Mixing and grinding according to the mass ratio of 1:15 to obtain a first mixture;

heating the first mixture to 400 ℃ at the speed of 5K/min under the inert gas atmosphere, and keeping the temperature for 2 hours to obtain a first reactant;

soaking the first reactant in 10mol/L H₂SO₄Stirring for 1h in an acidic medium at the temperature of 30 ℃ to obtain a second reactant;

and washing the second reactant to be neutral, drying the second reactant at the temperature of 40 ℃ for 3h, heating the second reactant to 550 ℃ at the speed of 5K/min in the atmosphere of inert gas, and keeping the temperature for 2h to obtain the copper-oxygen co-doped carbon nitrogen catalyst.

Example 6

Heating triazine nitrogen-containing heterocyclic organic compound to 500 ℃ at the speed of 10K/min and preserving heat for 4h to prepare g-C₃N₄；

Bis (8-hydroxyquinoline) copper (II) and the g-C₃N₄Mixing and grinding according to the mass ratio of 1:1 to obtain a first mixture;

heating the first mixture to 600 ℃ at a rate of 10K/min under an inert gas atmosphere, and keeping the temperature for 4 hours to obtain a first reactant;

soaking the first reactant in 0.1mol/L H₂SO₄Stirring for 6h at 100 ℃ in an acidic medium to obtain a second reactant;

and washing the second reactant to be neutral, drying the second reactant at the temperature of 100 ℃ for 10h, heating the second reactant to 550 ℃ at the speed of 10K/min in the atmosphere of inert gas after drying, and preserving heat for 4h to obtain the copper-oxygen co-doped carbon nitrogen catalyst.

Experimental example 1

The catalytic performance of the copper oxygen co-doped carbon nitrogen catalyst (SA) prepared in examples 1 to 3 and the copper oxygen co-doped carbon nitrogen catalyst (SB) prepared in examples 4 to 6 was tested by the following experimental method:

50ml of 40mg/L bisphenol A (BPA) aqueous solution is used as a model pollutant, catalysts are SA and SB with mass concentrations of 0.5g/L and 0.5g/L respectively, oxidants of SA catalysis are PDS and PMS, oxidants of SB catalysis are PMS, the mass concentrations of the oxidants of PMS and PMS are 160mg/L, 0.5ml of samples are taken in a given time interval, and a high performance liquid chromatograph is used for detecting the pollutant content so as to evaluate the catalytic performance of the catalysts.

The test results are shown in table 1:

TABLE 1

	5min BPA degradation Rate/%	10min BPA degradation Rate/%	15min BPA degradation/The%
				Example 1	85	90	97
Example 2	65	70	80
				Example 3	63	67	77
Example 4	93	96	99
				Example 5	73	84	90
Example 6	72	80	85

as can be seen from FIGS. 1 and 2, g-C is present in the Cu/O co-doped C/N catalyst₃N₄And has no CuO peak, and g-C is increased with the addition amount of the copper source₃N₄A peak of (a) is reduced;

as can be seen from FIGS. 3 and 4, the XPS-Ols spectra of SA and SB are related to the original g-C₃N₄The peak of C-O-Cu peak shifted by metal is more than that of C-O-Cu peak, which indicates the successful doping of Cu and O;

FIG. 6 is a graph showing that the copper-oxygen co-doped carbon-nitrogen catalyst (SB) prepared in example 4 of the present invention catalyzes PMS to degrade BPA in different systems;

as can be seen from FIGS. 5 and 6, the copper-oxygen alloy obtained in example 1 of the present inventionDoped carbon nitrogen catalyst (SA) and copper oxygen co-doped carbon nitrogen catalyst (SB) prepared in inventive example 3 compared to pure phase g-C₃N₄The degradation rate is improved by about 9 times, the degradation efficiency is respectively improved by 40 times and 35 times in the first 1 minute, and the high-efficiency degradation of pollutants is realized;

as is clear from fig. 8 and 9, the copper ion elution values of the copper oxygen-co-doped carbon nitrogen catalyst (SA) obtained in example 1 of the present invention and the copper oxygen-co-doped carbon nitrogen catalyst (SB) obtained in example 4 of the present invention were both excellent in stability when thermally regenerated after the third cycle.

FIG. 10 shows the results of experiments on inhibiting radicals in which the SA/PDS system formed by SA and PDS according to example 1 of the present invention degrades BPA, and shows that the SA/PDS system does not degrade BPA by radical reaction, has high efficiency of oxidant utilization, and has strong adaptability to different water qualities;

FIG. 11 is a free radical inhibition experiment result of BPA degradation by an SA/PMS system composed of SA and PMS obtained in example 1 of the present invention, which shows that the SA/PMS system does not rely on a free radical reaction to degrade BPA, has a small contribution of singlet oxygen, has high utilization efficiency for an oxidant, and has strong adaptability to different water qualities;

fig. 12 is a free radical inhibition experiment result of degradation of BPA by a SB/PMS system composed of SB and PMS according to example 4 of the present invention, which shows that the SB/PMS system does not rely on a free radical reaction to degrade BPA, and has a contribution of partial singlet oxygen, high utilization efficiency of an oxidant, and strong adaptability to different water qualities;

FIG. 13 is a drawing showing a preparation process of example 1 of the present inventionN of the obtained SA₂The adsorption-desorption isotherms show a typical type IV isotherm, indicating the mesoporous structure of O-CuCN, the pore size distribution curve confirming the presence of mesopores and macropores in O-CuCN, SA (33 m) due to the doping of Cu and O²g^-1) Has increased to g-C₃N₄(12m²g^-1) 2.8 times of the catalyst, the larger specific surface area leads to the exposure of more active sites, and more excellent catalytic performance is brought;

FIG. 14 shows the N of SB obtained in example 4 of the present invention₂The adsorption-desorption isotherms show a typical type IV isotherm, indicating the mesoporous structure of O-CuCN, the pore size distribution curve confirming the presence of mesopores and macropores in O-CuCN, SA (56 m) due to the doping of Cu and O²g^-1) Has increased to g-C₃N₄(12m²g^-1) 4.7 times of the catalyst, the larger specific surface area leads to the exposure of more active sites, and more excellent catalytic performance is brought;

FIG. 15 is an XPS survey of SA according to example 1 of the present invention; FIG. 15 shows the successful introduction of Cu and O;

FIG. 16 is an XPS survey of SB prepared in example 4 of the present invention; FIG. 16 shows the successful introduction of Cu and O;

FIG. 17 shows the resistance results for SA prepared in example 1 of the present invention; the electrical resistance of the SA surface is reduced after Cu and O are doped, so that the electron transfer is facilitated;

FIG. 18 shows the results of the electrical resistance of SB obtained in example 4 of the present invention, wherein the decrease in electrical resistance of the SB surface after Cu and O doping is more favorable for electron transfer;

FIG. 19 shows the degradation of SA obtained in example 1 of the present invention; in the presence of different anions, the SA-catalyzed PDS still maintains excellent degradation rate to BPA, and the advantage that the system is not influenced by the anions in the non-free radical reaction is reflected;

FIG. 20 shows the degradation of SB obtained in example 4 of the present invention; in the presence of different anions, the SB-catalyzed PDS still maintains excellent degradation rate to BPA, and the advantage that the system is not affected by the anions in the non-radical reaction is reflected;

FIG. 21 SA catalyzed PDS still maintains excellent degradation rate for BPA in pH range of 3-9, which shows the advantage of the system non-radical reaction, not affected by pH change;

FIG. 22 in the pH range of 3-9, the SB-catalyzed PMS still maintains excellent degradation rate for BPA, embodies the advantages of the system non-radical reaction and is not influenced by pH change;

FIG. 23 is g-C₃N₄Comparing the scanning electron microscope images of SA and SB, the layered stack structure of the catalyst is shown, no obvious metal cluster of Cu is found, and the high dispersion of Cu and O is shown;

FIG. 24 shows that in electron paramagnetic resonance experiments, tetramethylpiperidinol is used to capture singlet oxygen in SA + PMS system, and the existence of singlet oxygen is indicated by 3 continuous peaks;

FIG. 25 shows the electron paramagnetic resonance experiment using tetramethylpiperidinol to capture singlet oxygen in SA + PDS system, with no 3-peak indicating the absence of singlet oxygen;

FIG. 26 shows that in electron paramagnetic resonance experiments, tetramethylpiperidinol is used to capture singlet oxygen in a SB + PMS system, and the presence of singlet oxygen is indicated by a 3-fold peak;

FIG. 27 is an electron microscopy mapping diagram of the SA material, which shows the uniform distribution of four elements, namely C, N, Cu and O, and the successful doping of Cu and O elements;

FIG. 28 is an electron microscopy mapping graph of the SB material, showing the uniform distribution of the four elements C, N, Cu, O, successful doping of the Cu and O elements;

FIG. 29 is a Fourier transform infrared spectrum of SB material, which is measured for Fourier transform infrared spectra of different samples, as shown in FIG. 29, 1200-^-1Broad absorption peak in the range and 808cm^-1The peaks at (a) correspond to the stretching vibration of the aromatic CN ═ C heterocycle and the breathing vibration of the s-triazine unit, respectively. With g-C₃N₄And the mass ratio of 8-Cu was increased to 5, as can be clearly seen at 1200-1700cm^-1The broad absorption in the range is greatly reduced. The results indicate that the structural integrity of the aromatic C-N ═ C heterocycle is compromised. 1150-1300cm^-1Bands in the range correspond to C-O tensile vibration when g-C₃N₄And an increase in mass ratio of 8-CuThe peak value of C-O stretching vibration was highest at 5. Then as the 8-Cu content increases, g-C₃N₄The inherent structure of (a) is destroyed. The peak value of the CO stretching vibration is reduced along with the increase of the content, and the C-O bond in the catalyst is not the original bond. Is 8-Cu, but 8-Cu with g-C₃N₄Decomposition and recombination during pyrolysis. After 8-Cu addition, the complex with g-C due to sigma type bonds with Cu species on the catalyst surface₃N₄In contrast, the band for v (OH) is shifted to lower wavenumbers (3275 cm)^-1) This results in a shift of the central band of ν (OH) to lower wavenumbers.

FIG. 30 is an electron microscopy mapping chart of SA material, from FIG. 30, 808cm^-1The peak at (A) is due to respiratory vibration of the s-triazine unit and at 1200-^-1Broad absorption in the range. 1 tensile vibration due to aromatic CN ═ C heterocycles [27, 28]. When g-C₃N₄And the mass ratio of AC-Cu is less than 3, it can be clearly found at 1200-^-1Wide absorption in the range, which is greatly reduced. The results indicate that the structural integrity of the aromatic C-N ═ C heterocycles in tensile vibration has been compromised.

For g-C₃N₄The band of v (OH) is located at 3400-3700cm^-1. After the addition of AC-Cu, the v (OH) band is shifted to a lower wavenumber (3277 cm)^-1) This is due to the fact that the complexation of sigma-type bonds with Cu species on the catalyst surface will result in a bathochromic shift of v (OH) to lower wavenumbers.

FIG. 31 is a linear sweep voltammogram of SA material, showing a greater current density for SA, with an increase in current after addition of PDS showing that SA interacts with PDS to form a metastable reaction complex, and a further increase in current after addition of BPA. The improvement indicates that the non-radical reaction of the metastable reactive complex with bisphenol-A results in an increase in current density.

FIG. 32 is a linear sweep voltammogram of the SB material, showing greater current density for SB, and the increase in current after PMS addition indicates that SB interacts with PMS to form a metastable reactive complex.

FIG. 33 is a degradation diagram of different pollutants of SA materials, and the degradation of different pollutants such as methylene blue, methyl orange, rhodamine B, diclofenac sodium, bisphenol A and the like is explored. The SA/PMS system effectively removes bisphenol A, methyl orange and diclofenac sodium, but has poor degradation effect on methylene blue and rhodamine B, and shows that the non-free radical system has choice.

FIG. 34 is a degradation diagram of different pollutants of SB materials, and the degradation of different pollutants such as methylene blue, methyl orange, rhodamine B, diclofenac sodium, bisphenol A and the like is explored. The SB/PMS system effectively removes bisphenol A, rhodamine B and diclofenac sodium, but has poor degradation effect on methylene blue, and shows that the non-free radical system has selectivity.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. The preparation method of the copper-oxygen co-doped carbon-nitrogen catalyst is characterized by comprising the following steps:

2. The method for preparing a Cu-O co-doped C/N catalyst as claimed in claim 1, wherein the triazine nitrogen-containing heterocyclic organic compound is heated to 400-600 ℃ at a rate of 1-10K/min and then is kept at the temperature for 1-4h to obtain g-C₃N₄The method comprises the following steps:

3. The preparation method of the copper-oxygen co-doped carbon-nitrogen catalyst according to claim 1, wherein the copper acetylacetonate and the g-C are₃N₄The mass ratio of (A) to (B) is 1: 1-20.

4. The method for preparing a copper-oxygen co-doped carbon-nitrogen catalyst as claimed in claim 1, wherein the step of heating the first mixture at a rate of 1-10K/min to 400-600 ℃ and maintaining the temperature for 1-4h in an oxygen-free environment to obtain the first reactant comprises:

5. The preparation method of the copper-oxygen co-doped carbon-nitrogen catalyst according to claim 1, wherein the copper acetylacetonate and the g-C are mixed₃N₄Mixing and grinding to obtain a first mixture comprising:

6. The preparation method of the copper-oxygen co-doped carbon-nitrogen catalyst according to claim 5, wherein the bis (8-hydroxyquinoline) copper (II) and the g-C₃N₄The mass ratio of (A) to (B) is 1: 1-15.

7. The method for preparing a copper-oxygen co-doped carbon-nitrogen catalyst as claimed in claim 5, wherein the step of heating the first mixture at a rate of 5-10K/min to 400-600 ℃ and maintaining the temperature for 2-4h under an inert gas atmosphere to obtain the first reactant comprises:

8. The preparation method of the copper-oxygen co-doped carbon-nitrogen catalyst according to claim 1 or 5, characterized in thatIn that, the acidic medium is H₂SO₄、HNO₃And HCl, and the molar concentration of the acidic medium is 0.1-10 mol/L.

9. A copper-oxygen co-doped carbon-nitrogen catalyst, which is prepared by the preparation method of any one of claims 1 to 8.

10. The application of the copper-oxygen co-doped carbon-nitrogen catalyst is characterized in that the copper-oxygen co-doped carbon-nitrogen catalyst in claim 9 is used for catalytic oxidation of organic pollutants.