A graphene-wrapped nickel-nickel oxide catalyst and its application in the preparation of lactic acid

Abstract

The invention discloses a graphene-wrapped nickel-nickel oxide catalyst and its application in the preparation of lactic acid. Described graphene-wrapped nickel-nickel oxide catalyst is prepared by the following steps: (1) Ni(NO 3 ) 2 ·6H 2 O is nickel source, and citric acid is carbon source, and it is added in water successively, heats and stirs the mixture to form gel, and the mixture of gel is dried to obtain catalyst precursor; (2) catalyst precursor is placed in N 2 After heating and roasting in the air stream, the catalyst is obtained, then pickled, washed to neutral, and dried to obtain the graphene-wrapped nickel catalyst; (3) the graphene-wrapped nickel catalyst is oxidized to obtain the graphene-wrapped nickel-oxidized nickel catalyst. The graphene-wrapped nickel-nickel oxide catalyst adopted in the present invention can greatly improve the stability of the catalyst, protect metal ions from metal loss under alkaline conditions, and the recovered catalyst can be recycled for 1 to 6 times, and the catalyst activity of the catalyst is not obvious decline.

Description

technical field

[0001] The invention relates to the field of chemistry and chemical engineering, in particular to a graphene-wrapped nickel-nickel oxide catalyst and its application in the preparation of lactic acid. Background technique

[0002] Glycerol, also known as glycerol, is a simple polyol compound that was listed as one of the 12 biomass platform chemicals by the US Department of Energy in 2004. Glycerin is an important by-product of biodiesel, and its annual output far exceeds the market demand. Therefore, the catalytic conversion of glycerol into high value-added fine chemicals is conducive to improving the production efficiency of biodiesel and promoting the further development of biodiesel. Glycerol contains active hydroxyl functional groups, which can obtain high value-added fine chemicals through reactions such as oxidation, hydrogenolysis, hydrogenation, polymerization, dehydration, and dehydrogenation, and realize effective utilization.

[0003] Lactic ac...

Examples

Embodiment 1

[0031] The preparation of graphene-wrapped nickel-nickel oxide catalyst Ni-NiO@C includes the following steps:

[0032] (1) Preparation of catalyst precursor CA-Ni: 17.8g Ni(NO 3 ) 2 ·6H 2 O, 11.72g of citric acid was dissolved in 5mL of water, stirred at 70°C for 6h to gel, and then dried in a vacuum oven at 60°C for 10h to obtain the precursor powder CA-Ni;

[0033] (2) Preparation of encapsulated catalyst Ni@C: put the above precursor CA-Ni in 30mL / min N 2 In the airflow, heat up to 600°C and maintain it for 3 hours. The heating rate is 5°C / min. The gas is taken out and the calcined catalyst is poured into 1mol / L sulfuric acid solution and stirred at 70°C for 12h to wash away the insufficiently wrapped catalyst. nickel particles. The acid-washed catalyst was fully washed several times in distilled water to achieve neutrality, and then dried in a vacuum freeze dryer to obtain the catalyst Ni@C;

[0034] (3) Preparation of graphene-wrapped nickel-nickel oxide catalyst Ni-N...

Embodiment 2

[0037] The preparation of graphene-wrapped nickel-nickel oxide catalyst Ni-NiO@C includes the following steps:

[0038] (1) Preparation of catalyst precursor CA-Ni: 17.8g Ni(NO 3 ) 2 ·6H 2 O, 11.72g of citric acid was dissolved in 5mL of water, stirred at 60°C for 6h to gel, and then dried in a vacuum oven at 50°C for 12h to obtain the precursor powder CA-Ni;

[0039] (2) Preparation of encapsulated catalyst Ni@C: put the above precursor CA-Ni in 30mL / min N 2 In the airflow, heat up to 500°C and keep it for 4 hours, the temperature rise rate is 5°C / min, the gas is taken out, the roasted catalyst is poured into 1mol / L sulfuric acid solution, and stirred at 70°C for 12h to wash away the insufficiently wrapped catalyst. nickel particles. The acid-washed catalyst was fully washed several times in distilled water to achieve neutrality, and then dried in a vacuum freeze dryer to obtain the catalyst Ni@C;

[0040] (3) Preparation of graphene-wrapped nickel-nickel oxide catalyst ...

Embodiment 3

[0042] The preparation of graphene-wrapped nickel-nickel oxide catalyst Ni-NiO@C includes the following steps:

[0043] (1) Preparation of catalyst precursor CA-Ni: 17.8g Ni(NO 3 ) 2 ·6H 2 O, 11.72g of citric acid was dissolved in 5mL of water, stirred at 80°C for 6h to gel, and then placed in a vacuum oven at 70°C for 8h to obtain the precursor powder CA-Ni;

[0044] (2) Preparation of encapsulated catalyst Ni@C: put the above precursor CA-Ni in 30mL / min N 2 In the airflow, heat up to 700°C and maintain it for 2 hours. The heating rate is 5°C / min. The gas is taken out and the calcined catalyst is poured into a 1mol / L sulfuric acid solution and stirred at 70°C for 12 hours to wash away the insufficiently wrapped catalyst. nickel particles. The acid-washed catalyst was fully washed several times in distilled water to achieve neutrality, and then dried in a vacuum freeze dryer to obtain the catalyst Ni@C;

[0045] (3) Preparation of graphene-wrapped nickel-nickel oxide cata...

technical field

[0001] The invention relates to the field of chemistry and chemical engineering, in particular to a graphene-wrapped nickel-nickel oxide catalyst and its application in the preparation of lactic acid. Background technique

[0002] Glycerol, also known as glycerol, is a simple polyol compound that was listed as one of the 12 biomass platform chemicals by the US Department of Energy in 2004. Glycerin is an important by-product of biodiesel, and its annual output far exceeds the market demand. Therefore, the catalytic conversion of glycerol into high value-added fine chemicals is conducive to improving the production efficiency of biodiesel and promoting the further development of biodiesel. Glycerol contains active hydroxyl functional groups, which can obtain high value-added fine chemicals through reactions such as oxidation, hydrogenolysis, hydrogenation, polymerization, dehydration, and dehydrogenation, and realize effective utilization.

[0003] Lactic ac...

Examples

Embodiment 1

[0031] The preparation of graphene-wrapped nickel-nickel oxide catalyst Ni-NiO@C includes the following steps:

[0032] (1) Preparation of catalyst precursor CA-Ni: 17.8g Ni(NO 3 ) 2 ·6H 2 O, 11.72g of citric acid was dissolved in 5mL of water, stirred at 70°C for 6h to gel, and then dried in a vacuum oven at 60°C for 10h to obtain the precursor powder CA-Ni;

[0033] (2) Preparation of encapsulated catalyst Ni@C: put the above precursor CA-Ni in 30mL / min N 2 In the airflow, heat up to 600°C and maintain it for 3 hours. The heating rate is 5°C / min. The gas is taken out and the calcined catalyst is poured into 1mol / L sulfuric acid solution and stirred at 70°C for 12h to wash away the insufficiently wrapped catalyst. nickel particles. The acid-washed catalyst was fully washed several times in distilled water to achieve neutrality, and then dried in a vacuum freeze dryer to obtain the catalyst Ni@C;

[0034] (3) Preparation of graphene-wrapped nickel-nickel oxide catalyst Ni-N...

Embodiment 2

[0037] The preparation of graphene-wrapped nickel-nickel oxide catalyst Ni-NiO@C includes the following steps:

[0038] (1) Preparation of catalyst precursor CA-Ni: 17.8g Ni(NO 3 ) 2 ·6H 2 O, 11.72g of citric acid was dissolved in 5mL of water, stirred at 60°C for 6h to gel, and then dried in a vacuum oven at 50°C for 12h to obtain the precursor powder CA-Ni;

[0039] (2) Preparation of encapsulated catalyst Ni@C: put the above precursor CA-Ni in 30mL / min N 2 In the airflow, heat up to 500°C and keep it for 4 hours, the temperature rise rate is 5°C / min, the gas is taken out, the roasted catalyst is poured into 1mol / L sulfuric acid solution, and stirred at 70°C for 12h to wash away the insufficiently wrapped catalyst. nickel particles. The acid-washed catalyst was fully washed several times in distilled water to achieve neutrality, and then dried in a vacuum freeze dryer to obtain the catalyst Ni@C;

[0040] (3) Preparation of graphene-wrapped nickel-nickel oxide catalyst ...

Embodiment 3

[0042] The preparation of graphene-wrapped nickel-nickel oxide catalyst Ni-NiO@C includes the following steps:

[0043] (1) Preparation of catalyst precursor CA-Ni: 17.8g Ni(NO 3 ) 2 ·6H 2 O, 11.72g of citric acid was dissolved in 5mL of water, stirred at 80°C for 6h to gel, and then placed in a vacuum oven at 70°C for 8h to obtain the precursor powder CA-Ni;

[0044] (2) Preparation of encapsulated catalyst Ni@C: put the above precursor CA-Ni in 30mL / min N 2 In the airflow, heat up to 700°C and maintain it for 2 hours. The heating rate is 5°C / min. The gas is taken out and the calcined catalyst is poured into a 1mol / L sulfuric acid solution and stirred at 70°C for 12 hours to wash away the insufficiently wrapped catalyst. nickel particles. The acid-washed catalyst was fully washed several times in distilled water to achieve neutrality, and then dried in a vacuum freeze dryer to obtain the catalyst Ni@C;

[0045] (3) Preparation of graphene-wrapped nickel-nickel oxide cata...

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