Preparation method of graphene/titanium dioxide composite photocatalyst

Abstract

The invention relates to a preparation method of a graphene / titanium dioxide composite photocatalyst, which comprises the following steps: dissolving oxidized graphite in an organic solvent and obtaining oxidized graphene dispersion by ultrasonic processing; adding titanium salt precursor to the oxidized graphene dispersion and stirring evenly; transferring the mixed dispersion into a hydrothermal reaction kettle and reacting at 120-200 DEG C for 4-20 hours; respectively cleaning the product of the reaction by absolute ethyl alcohol and de-ionized water; and drying in vacuum at 40-80 DEG C for 8-24 hours to obtain the graphene / titanium dioxide composite photocatalyst. The invention has the advantages of common and easily obtained raw material, low cost and simple and safe preparation process, and in the obtained product, TiO2 particles can be evenly dispersed on the surface of the graphene, and stronger acting force is formed between the TiO2 particles and the surface of the graphene,thereby avoiding aggregation of the particles and effectively preventing restacking of graphene laminas. The graphene / titanium dioxide composite photocatalyst has good photocatalysis activity due to structural advantages and has potential application value in the fields of environment protection and solar cells.

Description

technical field

[0001] The invention relates to a method for preparing a photocatalyst, in particular to a method for preparing a graphene / titanium dioxide composite photocatalyst by a hydrothermal method, and belongs to the technical field of photocatalysis. Background technique

[0002] Since 1972 Fijishima et al. in TiO 2 Since the phenomenon of water splitting was found on the electrode surface, TiO 2 As a photocatalyst, it has been widely studied by scientists from all over the world. Under UV light, electrons from TiO 2 The valence band is excited to the conduction band, and positively charged holes are generated on the valence band, so that TiO 2 Has photocatalytic activity. However, the recombination rate of electron-hole pairs generated by photoexcitation is very fast, and the recombination time is about 10 -9 Second. while TiO 2 The time required for the chemical reaction with the organic pollutants adsorbed on its surface is about 10 -8 -10 -3 Second. Th...

Examples

Embodiment 1

[0019] Add 30 mg of graphite oxide to 30 mL of isopropanol, and sonicate for 1 hour to obtain a graphene oxide dispersion. Then 5 mL of n-butyl titanate was added and stirred for 30 minutes, followed by the addition of 1 mL of deionized water and continued stirring for 30 minutes to obtain a beige gel. The gel was transferred to a hydrothermal reactor and reacted at 180°C for 8 hours. The hydrothermal product was washed several times by centrifugation with ethanol and deionized water respectively, placed in a vacuum oven, and dried at 60° C. for 12 hours to obtain a graphene / titanium dioxide composite photocatalyst.

[0020] figure 1 The XRD figure of the graphene / titanium dioxide composite material that is made in this embodiment. All the diffraction peaks in the figure correspond to TiO 2 In the anatase phase, the characteristic diffraction peak of graphite oxide at 2θ=10.7° disappeared, indicating that the hydrothermal reaction effectively reduced graphite oxide to graph...

Embodiment 2

[0022] Add 10 mg of graphite oxide to 30 mL of isopropanol, and sonicate for 40 minutes to obtain a graphene oxide dispersion. Then 5 mL of n-butyl titanate was added and stirred for 30 minutes, followed by the addition of 1 mL of deionized water and continued stirring for 20 minutes to obtain a beige gel. The gel was transferred to a hydrothermal reactor and reacted at 140°C for 12 hours. The hydrothermal product was washed several times by centrifugation with ethanol and deionized water respectively, placed in a vacuum oven, and dried at 50° C. for 18 hours to obtain a graphene / titanium dioxide composite photocatalyst.

Embodiment 3

[0024] Add 50 mg of graphite oxide to 30 mL of ethanol, and ultrasonicate for 1 hour to obtain a graphene oxide dispersion. Then 5 mL of n-butyl titanate was added and stirred for 30 minutes, followed by the addition of 1 mL of deionized water and continued stirring for 30 minutes to obtain a beige gel. The gel was transferred to a hydrothermal reactor and reacted at 200°C for 6 hours. The hydrothermal product was washed several times by centrifugation with ethanol and deionized water respectively, placed in a vacuum oven, and dried at 70° C. for 10 hours to obtain a graphene / titanium dioxide composite photocatalyst.

technical field

[0001] The invention relates to a method for preparing a photocatalyst, in particular to a method for preparing a graphene / titanium dioxide composite photocatalyst by a hydrothermal method, and belongs to the technical field of photocatalysis. Background technique

[0002] Since 1972 Fijishima et al. in TiO 2 Since the phenomenon of water splitting was found on the electrode surface, TiO 2 As a photocatalyst, it has been widely studied by scientists from all over the world. Under UV light, electrons from TiO 2 The valence band is excited to the conduction band, and positively charged holes are generated on the valence band, so that TiO 2 Has photocatalytic activity. However, the recombination rate of electron-hole pairs generated by photoexcitation is very fast, and the recombination time is about 10 -9 Second. while TiO 2 The time required for the chemical reaction with the organic pollutants adsorbed on its surface is about 10 -8 -10 -3 Second. Th...

Examples

Embodiment 1

[0019] Add 30 mg of graphite oxide to 30 mL of isopropanol, and sonicate for 1 hour to obtain a graphene oxide dispersion. Then 5 mL of n-butyl titanate was added and stirred for 30 minutes, followed by the addition of 1 mL of deionized water and continued stirring for 30 minutes to obtain a beige gel. The gel was transferred to a hydrothermal reactor and reacted at 180°C for 8 hours. The hydrothermal product was washed several times by centrifugation with ethanol and deionized water respectively, placed in a vacuum oven, and dried at 60° C. for 12 hours to obtain a graphene / titanium dioxide composite photocatalyst.

[0020] figure 1 The XRD figure of the graphene / titanium dioxide composite material that is made in this embodiment. All the diffraction peaks in the figure correspond to TiO 2 In the anatase phase, the characteristic diffraction peak of graphite oxide at 2θ=10.7° disappeared, indicating that the hydrothermal reaction effectively reduced graphite oxide to graph...

Embodiment 2

[0022] Add 10 mg of graphite oxide to 30 mL of isopropanol, and sonicate for 40 minutes to obtain a graphene oxide dispersion. Then 5 mL of n-butyl titanate was added and stirred for 30 minutes, followed by the addition of 1 mL of deionized water and continued stirring for 20 minutes to obtain a beige gel. The gel was transferred to a hydrothermal reactor and reacted at 140°C for 12 hours. The hydrothermal product was washed several times by centrifugation with ethanol and deionized water respectively, placed in a vacuum oven, and dried at 50° C. for 18 hours to obtain a graphene / titanium dioxide composite photocatalyst.

Embodiment 3

[0024] Add 50 mg of graphite oxide to 30 mL of ethanol, and ultrasonicate for 1 hour to obtain a graphene oxide dispersion. Then 5 mL of n-butyl titanate was added and stirred for 30 minutes, followed by the addition of 1 mL of deionized water and continued stirring for 30 minutes to obtain a beige gel. The gel was transferred to a hydrothermal reactor and reacted at 200°C for 6 hours. The hydrothermal product was washed several times by centrifugation with ethanol and deionized water respectively, placed in a vacuum oven, and dried at 70° C. for 10 hours to obtain a graphene / titanium dioxide composite photocatalyst.

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