Method for preparing graphene oxide through microfluidics

Abstract

The invention discloses a method for preparing graphene oxide through microfluidic control, which comprises the following steps: preparation of a first premixed solution: mixing graphite powder and a first intercalator to obtain the first premixed solution; preparing a second premixed solution, namely mixing an oxidizing agent and a second intercalator to obtain the second premixed solution; performing micro-flow mixing: feeding the first premixed solution and the second premixed solution into a micro-mixer for mixing to obtain a mixed suspension of graphite, an oxidizing agent and an intercalator; performing micro-flow reaction: feeding the mixed suspension into a micro-channel reactor for reaction; performing separation: preliminarily separating graphene oxide and an acid solution containing an oxidizing agent in a reaction mixture flowing out of the microchannel reactor, collecting the graphene oxide, and carrying out quenching reaction; and performing purification: washing the collected graphene oxide to finally obtain a high-purity graphene oxide aqueous dispersion liquid or a graphene oxide filter cake.

Description

technical field [0001] The invention relates to the field of graphene oxide preparation, in particular to a method for preparing graphene oxide using microfluidic technology. Background technique [0002] Graphene, as a single atomic layer two-dimensional material formed by periodic repeated arrangements of carbon six-membered rings, has attracted much attention due to its excellent electrical, thermal, and mechanical properties since its inception, and is considered to be a functional material and structural material with great potential . The top priority for the development of graphene in important fields such as energy, environment, biomedicine, and electronic devices is to solve the problem of efficient preparation of graphene. The reduced graphene oxide method is considered to be one of the easiest methods to scale up and realize large-scale production of graphene. , by chemically modifying a large number of oxygen-containing functional groups on the graphite sheet, w...

AI Technical Summary

Problems solved by technology

However, there are still many problems in the reported improved Hummers method: first, the oxidation rate of graphite is restricted by the slow diffusion of active substances between pre-intercalated graphite layers, and the reaction time is long; 2 o 7 There is a risk of explosion at high temperature, and the reaction safety hazard is great; 3. There are many steps in the batch process, and the product quality is difficult to accurately control

[0004] Existing reports use stronger oxidants to quickly prepare graphene oxide. The invention patent "CN104310385A A Fast and Green Method for Preparing Single-layer Graphene Oxide" uses potassium ferrate as an oxidant and reacts at -10-80°C for 0.5- 24h, although the reaction time can be shortened to 0.5h, but the use of more strong oxidants leads to more serious environmental problems

The invention patent "CN106882803A A method and device for preparing graphene oxide" uses a multi-stage pipeline reactor for mixing, oxidation and reduction respectively, which strengthens the reaction control and realizes continuous production, but still uses conventional pipelines, in which the oxidation The steps still take 1-4h

Invention patent "CN102471068B Manufacturing method of nanometer-sized graphene materials and its manufacturing equipment" introduced microchannel equipment for the first time to prepare graphene oxide and stripped and reduced it in a vertical fluidized bed furnace, realizing continuous production of graphene, but no Realize the controllable preparation of graphene oxide oxidation degree, and the yield of graphite oxide is not specified

In addition, the intercalation reaction and oxidation reaction in the microreactor of this patent are carried out at the same time, and it is difficult to achieve effective regulation of the oxidation reaction alone

And the quenching step is carried out in the microreactor, and the quenching step involves a quenching agent (such as H 2 o 2 ) reacts with the unreacted oxidant, a large amount of gas will be produced, which will easily cause the problem of hindering the reaction process and clogging in the microchannel