Preparation And Properties Of Multifunctional Graphene Aerogels

Single-layer graphene is a new type of nanomaterial with excellent mechanical,electrical,thermal,and optical properties.It has a wide range of applications in the fields of energy storage,electronic devices,environmental remediation,and composite materials.However,these excellent properties are limited to defect-free graphene and are restricted to the nanometer scale.How to make its excellent properties truly useful for people is worth exploring.The simplest way is to make graphene three-dimensional self-assembly into an aerogel,which not only inherits the excellent characteristics of the structural unit,but also has the characteristics of low density,high porosity,and large specific surface area.Although the research on graphene aerogel has been fruitful,there are still a series of important problems,which greatly restrict its performance improvement,macro-preparation and applications in many fields,such as:how to use simple preparation to achieve mass production of graphene aerogels?How to reasonably design and construct graphene aerogels to achieve ultra-light and high elastic properties simultaneously?In response to the above two important issues,this paper launched corresponding research and explored the macro-preparation of ultra-light elastic graphene aerogel,and its application potential in aspects such as mechanical sensing and adsorption.Na OH is used to induce large sheets of graphene oxide to form liquid crystals at low concentrations.After glucose is added,it is hydrothermally reduced to form highly ordered graphene aerogels(HOGA).Compared with L-ascorbic acid as a reducing agent,the obtained random-pore aerogel has better anti-fatigue properties,and can recover its maximum height and maximum stress within a few minutes after the cycle test.HOGA has a stable force-electricity conversion characteristic.Based on this,we have prepared a mechanical sensor that can detect the human body's movement state.The change of human gait during exercise can be converted into corresponding electrical signals to be collected.Different walking postures correspond to electrical signals.The signals are significantly different.In addition,HOGA has ultra-fast and ultra-high adsorption capacity for organic solvents.Depending on the type of solvent,it can adsorb 80-166times its own weight.The maximum adsorption rate can reach 83g g^-1 s^-1,which is the highest value reported so far.Graphene aerogels that can be dried at atmospheric pressure(PRGA)are prepared by a stepwise reduction method,which replaces the complex freeze-drying process and is expected to realize the large-scale preparation of graphene aerogels(such as 2000 cm³).By adjusting the pretreatment time and the second reduction time,the PRGA with the best volume and mechanical properties can be obtained.Depending on the type of organic solvent,it can absorb 40-82 times its own weight,and it can be saturated within1s.This article proposes the alkali-induced method to prepare HOGA and the distributed reduction method to prepare PRGA.HOGA is integrated into foam cotton to detect changes in human movement,and HOGA also has the highest absorption rate of organic solvents.PRGA is expected to achieve large-scale preparation of graphene aerogels and also possess the potential for environmental remediation.