CN112094173B - For photocatalytic CH4And O2Method for producing liquid chemicals by reaction - Google Patents

Abstract

The invention discloses a photocatalytic CH₄And O₂A method for generating organic chemicals by reaction, belonging to the technical field of advanced material chemistry. The catalyst used was Ni nanoclusters with a precise nanostructure. The invention utilizes the special energy level structure of the Ni nanocluster and utilizes the light energy to convert CH₄And O₂Selectively converted into organic chemicals, has the advantages of good selectivity, mild reaction conditions, easy separation of products and catalysts, convenient recycling, easy activation and the like, and has good application prospect.

Description

For photocatalytic CH4And O2Method for producing liquid chemicals by reaction

Technical Field

The invention relates to an application of a nickel catalyst in methane conversion, in particular to an application of the nickel catalyst in methane and oxygen photocatalytic conversion, belonging to the technical field of advanced material chemistry.

Background

Natural gas is an important fossil fuel, the main component of which is methane, and the worldwide natural gas reserves are continuously increasing with the breakthrough of exploration technologies. Because of its relatively low cost, high heat value and no pollution, it is widely used as fuel in daily life, new power plant and industrial production. Besides being used as fuel, the methane in the natural gas is used as chemical raw materials to directly produce high-value-added chemicals, so that the method is a direct, effective and wide-prospect natural gas utilization method. However, the structure of methane is extremely stable, the carbon-hydrogen bond energy is high, the polarity is weak, the solubility is small, and how to convert methane with high selectivity is a major challenge in the chemical field. The direct conversion reaction of methane has heretofore generally required the use of noble metals (platinum, palladium, etc.) as catalysts and severe conditions such as high temperatures. Therefore, the development of a high-efficiency, high-selectivity, cheap and mild catalytic conversion mode to further meet the requirements of industrial production on environmental protection and cost control is a direction continuously sought by chemists.

Metal nanoclusters are generally composed of several to several hundred metal atoms, in the sub-nanometer size range, with extremely high specific surface area and quantum size effects. Due to the determined number of atoms and the precise structure, the material has a unique electronic structure and energy level structure. The characteristics enable the metal nano-cluster to realize special selectivity different from that of the traditional nano-catalyst in the catalysis process, and the precise structure of the metal cluster also provides a bridge and means for exploring the catalysis mechanism in the atom precision.

Due to the extremely small size, the metal nanocluster has an energy level structure similar to molecules, and is different from a continuous energy band of bulk metal, so that the metal nanocluster can absorb photons in a specific waveband to generate photo-generated electrons and holes, and the catalytic chemical reaction is carried out under mild conditions. The photocatalytic reaction of metal nano-clusters has been reported, the common application of noble metal clusters such as gold and silver is still, the degradation of pollutants and the selective synthesis of specific organic matters can be realized under the irradiation of light, but the catalyst is extremely expensive. The nickel nanocluster with low cost also has an obvious ultraviolet-visible spectrum characteristic peak, and if the absorption conversion of the nickel nanocluster to ultraviolet light and visible light can be utilized to realize the direct selective conversion of methane by oxygen, the cost can be obviously reduced, and the threshold is reduced for further production application research. And the temperature condition required by the nano-cluster photocatalysis is mild, and the selectivity is high, so that the research on the direct conversion of the nickel nano-cluster photocatalysis methane and oxygen into organic chemicals is of great significance.

Disclosure of Invention

The technical problem solved by the invention is as follows: the invention provides a photocatalytic CH₄And O₂The method for producing methanol and formic acid by reaction uses nickel nano cluster as catalyst, and under the condition of light and mild temp. the CH is converted₄Is an organic chemical. The invention will have Ni of precise structure₄、Ni₅、Ni₆The nanoclusters are used for photocatalysis, the specific energy level structure of the Ni nanoclusters is utilized to absorb and convert light energy, extremely stable carbon-hydrogen bonds in methane molecules are broken, and methane is efficiently converted into organic chemicals by taking oxygen as an oxidant.

In order to solve the technical problem, the invention adds Ni under the condition of light assistance₄、Ni₅、Ni₆Nanocluster catalyst for catalyzing CH₄And O₂An implementation method for preparing organic chemicals by reaction comprises the following steps:

1)Ni₄、Ni₅、Ni₆preparation of nanocluster catalyst

Dissolving a nickel source and a surfactant in a solvent to prepare a solution A;

adding mercaptan into the solution A, wherein the mass ratio of the mercaptan to the nickel is 5:1, and adding a sodium borohydride solution for reduction, wherein the mass ratio of the sodium borohydride to the nickel is 15: 2, reduction to form Ni₄、Ni₅、Ni₆A nanocluster mixture;

vacuum rotary evaporation, washing with ethanol, extracting with acetonitrile, and separating Ni by thin layer chromatography₄、Ni₅、 Ni₆Nanoclusters of Ni by impregnation₄、Ni₅、Ni₆Loading nano cluster on carrier to obtain loaded Ni₄、Ni₅、 Ni₆A nanocluster catalyst.

The nickel source comprises: a salt containing nickel; preferably a divalent nickel salt, such as a divalent nickel salt comprising: one or more of nickel chloride, nickel nitrate or nickel acetate; preferably nickel chloride (e.g., NiCl)₂·6H₂O)。

The surfactant includes: a cationic surfactant; preferably a quaternary ammonium salt type cationic surfactant, such as the quaternary ammonium salt type cationic surfactant including: one or more of tetraoctyl ammonium bromide, tetrabutyl ammonium chloride or octadecyl trimethyl ammonium chloride; preferably tetraoctylammonium bromide (TOAB).

The solvent comprises: one or more of an alcohol, an ether, a ketone, an aromatic hydrocarbon, or water; preferably ethers, such as tetrahydrofuran, diethyl ether, dioxane; tetrahydrofuran is preferred.

The thiols include: one or more of phenethyl mercaptan, 2, 4-dimethyl thiophenol, 4-tert-butyl thiophenol, cyclohexyl mercaptan, benzyl mercaptan, etc.; preferably phenethyl mercaptan.

The Ni₆The nano-cluster is a six-membered ring core, and is in a double-crown shape by matching with a sulfur atom.

The carrier includes: metal oxides or non-metal oxides such as titanium dioxide, cerium oxide, aluminum oxide, silicon dioxide, etc.; preferably titanium dioxide.

2) Photocatalytic methane and oxygen conversion by Ni nano-cluster catalyst

Adding the Ni nano-cluster catalyst into a photocatalytic reaction kettle, adding a solvent as a dispersoid, and filling CH with a certain pressure₄And O₂Vigorous stirring was performed while illuminating with a light source through the window.

The photocatalytic reaction kettle is provided with an optical window which can transmit ultraviolet light and visible light;

the solvent comprises: water and an organic solvent;

the CH₄And O₂The pressure range of (A) is preferably 1.5-4 MPa;

the light source includes: light sources emitting ultraviolet light and visible light, such as xenon lamps, mercury lamps, LED lamps, preferably xenon lamps;

the illumination time is 0.5-24 h, preferably 2 h;

the reaction temperatures used were: 25 ℃ to 100 ℃, preferably 25 ℃.

In the present invention, Ni is obtained by reducing a solution containing nickel and a surfactant with mercaptan and sodium borohydride₆Nanoclusters of Ni₆Loading nano cluster on carrier to obtain the invented productUsing Ni₆A nanocluster catalyst. In the invention, Ni₆Application of nanocluster catalyst to CH₄And O₂The organic chemical is obtained with high selectivity by the photocatalytic reaction of (2).

The invention has the beneficial effects that:

the invention utilizes the accurate atom number Ni₄、Ni₅、Ni₆The special energy level structure of the nano-cluster can convert light energy and efficiently and selectively convert CH₄And O₂Photocatalytic conversion to organic chemicals. Meanwhile, the method has the advantages of good selectivity, mild reaction conditions, easy separation of products and catalysts, convenient recycling, easy activation and the like, and has good application prospect.

Drawings

The invention will be further explained with reference to the drawings.

FIG. 1 is Ni₄、Ni₅、Ni₆UV-Vis absorption spectra of nanoclusters;

FIG. 2 is Ni₄(a)、Ni₅、(b)Ni₆(c) Structure diagram of nanoclusters (dark atom represents Ni and light atom represents ligand sulfur);

FIG. 3 shows light-assisted Ni₄、Ni₅、Ni₆The catalyst catalyzes the reaction of methane and oxygen, and the single-pass conversion rate of the methane is a bar chart;

FIG. 4 shows light-assisted Ni₆The catalyst catalyzes the reaction of methane and oxygen, and the single-pass conversion rate of the methane is a bar chart;

FIG. 5 shows Ni under light conditions₆The catalyst catalyzes the methane and oxygen to react, the bar chart of the product selectivity;

FIG. 6 shows Ni under light conditions₆The catalyst catalyzes the reaction of methane and oxygen, and the relationship diagram of the single-pass conversion rate of methane and the load capacity of Ni clusters;

FIG. 7 shows Ni under light conditions₆The catalyst catalyzes the reaction of methane and oxygen, and the single-pass conversion rate of the methane is in a relation graph with the methane pressure;

FIG. 8 shows Ni under light conditions₆The catalyst catalyzes the reaction of methane and oxygen, and the conversion per pass of the methane is related to the temperatureDrawing;

Detailed Description

Ni used in the invention₄、Ni₅、Ni₆Clusters can be identified by UV-Vis spectral characterization (fig. 1), which are double-crown with nickel polycyclic rings as core and sulfur atom ligands on both sides of the polycyclic rings (fig. 2).

The catalyst used in the invention can show good catalytic effect on different carriers, and has selectivity of completely converting into liquid organic chemicals of methanol and formic acid and higher conversion rate (figures 3 and 4). The conversion rate of the reaction is positively correlated with the Ni cluster load, the reaction gas pressure and the temperature. Can be in CH₄The pressure ratio of O2 is 2:1, and the good effect is achieved at normal temperature.

Example 1

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₄Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₄/TiO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₄/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 2

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₅Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₅/TiO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₅/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 3

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Rotary evaporating solution D at 40 deg.C, leaving solid with dichloro-benzeneDissolving and separating methane to obtain a solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₆Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₆/TiO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₆/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 4

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₆Nanoclusters were impregnated with 0.1000g of cerium oxide (CeO) in dichloromethane as solvent₂) To obtain Ni₆Nanocluster catalyst Ni₆/CeO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₆/CeO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 5

0.0482g of chlorine were weighed outNickel (NiCl)₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₆Nanoclusters impregnated with 0.1000g of Silica (SiO) in dichloromethane₂) To obtain Ni₆Nanocluster catalyst Ni₆/SiO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₆/SiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 6

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₆Nanoclusters are impregnated with 0.1000g of zirconium dioxide (ZrO) in dichloromethane₂) To obtain Ni₆Nanocluster catalyst Ni₆/ZrO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₆/ZrO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 7

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0057g of Ni₆Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₆/TiO₂(1％Ni)。

50mg Ni was added to 100mL Teflon liner₆/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 8

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylbromideAmmonium (TOAB), dissolved in 15mL tetrahydrofuran to form solution A, was stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0171g of N is taken_i6Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₆/TiO₂(3％Ni)。

50mg Ni was added to 100mL Teflon liner₆/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 9

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0228g of Ni was taken₆Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₆/TiO₂(4％Ni)。

50mg Ni was added to 100mL Teflon liner₆/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 10

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₆Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₆/TiO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₆/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And CH of 0.5MPa₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 11

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₆Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₆/TiO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₆/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 1MPa of CH₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 12

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₆Nanoclusters impregnated with 0.1000g of methylene chloride as solventTitanium (TiO)₂) To obtain Ni nano cluster catalyst Ni₆/TiO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₆/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And CH of 3MPa₄The mixture was stirred vigorously, the temperature was set at 25 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 13

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₆Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₆/TiO₂(2％Ni)。

50mg of Ni6/TiO was added to a 100mL polytetrafluoroethylene liner₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 80 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

Example 14

0.0482g of nickel chloride (NiCl) were weighed out₂·6H₂O) and 0.1290g of tetraoctylammonium bromide (TOAB) in 15mL of tetrahydrofuran to form a solution a, which is stirred in an ice bath.

Adding 140.0 mu L of phenethyl mercapto into the solution A, and stirring and mixing uniformly to obtain a solution B.

5mL of NaBH dissolved in 0.0767g₄Adding the aqueous solution into the solution B, and stirring and mixing uniformly to obtain a solution C.

Solution C was rotary evaporated at 40 ℃. The sample was washed with ethanol 3-5 times, and then dissolved and separated with acetonitrile to obtain a solution D.

Solution D was rotary evaporated at 40 ℃ and the remaining solid was dissolved in dichloromethane and isolated as solution E. Separation of Ni by thin layer chromatography₄、Ni₅、Ni₆A nanocluster.

0.0114g of Ni₆Nanoclusters of titanium dioxide (TiO) impregnated in 0.1000g of methylene chloride as solvent₂) To obtain Ni nano cluster catalyst Ni₆/TiO₂(2％Ni)。

50mg Ni was added to 100mL Teflon liner₆/TiO₂15mL of ultrapure water was added thereto, and 1MPa of O was charged₂And 2MPa of CH₄The mixture was stirred vigorously, the temperature was set at 100 ℃ and simultaneously irradiated with a 210W xenon lamp through the window for 2 h.

The invention is not limited to the specific technical solutions described in the above embodiments, and all technical solutions formed by equivalent substitutions are within the scope of the invention as claimed.

Claims (6)

1. For photocatalytic CH₄And O₂A method of reacting to form a liquid chemical, characterized by: the method applies nickel nanoclusters loaded on a carrier to CH₄In the photocatalytic conversion, a supported nickel nano cluster is used as a catalyst and is dispersed in a solvent, and CH is catalyzed by light source irradiation₄And O₂Reacting to generate methanol or formic acid, wherein the nickel nanocluster of the supported nickel nanocluster catalyst is Ni with a multi-ring nickel atom inner core₄、 Ni₅、Ni₆Nanoclusters;

the light source is as follows: a light source emitting ultraviolet light and visible light;

the solvent is as follows: water or an organic liquid;

the pressures used were: 0.1-5 MPa;

the reaction temperatures used were: 25-100 ℃;

the reaction times used were: 0.5-24 h;

the Ni₄、 Ni₅、Ni₆The preparation method of the nano-cluster comprises the following steps:

dissolving a nickel source and a surfactant in a solvent to prepare a solution A;

adding mercaptan into the solution A, wherein the mass ratio of the mercaptan to the nickel is 5:1, and adding a sodium borohydride solution for reduction, wherein the mass ratio of the sodium borohydride to the nickel is 15: 2, reducing to generate Ni nano-clusters;

vacuum rotary evaporating, washing with ethanol, extracting with acetonitrile and dichloromethane, and separating Ni by thin layer chromatography₄、 Ni₅、Ni₆Nanoclusters; loading the Ni nano-cluster on a carrier by using an impregnation method to obtain a loaded Ni nano-cluster catalyst;

the nickel source is as follows: one or more of nickel chloride, nickel nitrate or nickel acetate;

the surfactant is: one or more of tetraoctyl ammonium bromide, tetrabutyl ammonium chloride or octadecyl trimethyl ammonium chloride;

the solvent is as follows: one or more of an alcohol, an ether, a ketone, an aromatic hydrocarbon, or water;

the mercaptan is: one or more of phenethyl mercaptan, 2, 4-dimethyl thiophenol, 4-tert-butyl thiophenol, cyclohexyl mercaptan and benzyl mercaptan;

the carrier is as follows: titanium dioxide, cerium dioxide, aluminum oxide or silicon dioxide.

2. The photocatalyst for CH of claim 1₄And O₂A method of reacting to form a liquid chemical, characterized by: the light source is as follows: xenon lamps, mercury lamps or LED lamps.

3. The photocatalyst for CH of claim 2₄And O₂A method of reacting to form a liquid chemical, characterized by: the light source is as follows: xenon lamps.

4. According to claim1 for photocatalytic CH₄And O₂A method of reacting to form a liquid chemical, characterized by: the CH₄:O₂The pressure ratio was 2: 1.

5. The photocatalyst for CH of claim 1₄And O₂A method of reacting to form a liquid chemical, characterized by: the reaction times used were: and 2 h.

6. The photocatalyst for CH of claim 1₄And O₂A method of reacting to form a liquid chemical, characterized by: the temperature is as follows: at 25 ℃.

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