Green Fabrication Of Carbon Nanomaterials And The Study Of Their Electrochemical Properties

As we move forward into the future,electrochemical technology plays an important role in many fields,especially efficient energy storage and conversion technology.Carbon is one of the most abundant elements in the earth,and carbon materials are an important functional materials.Carbon nanomaterials,due to their excellent properties,such as high electrical conductivity,unique geometric structure,high specific surface area,chemical inertness and excellent water solubility,have attracted wide attentions in recent years.Carbon nanomaterials are widely studied in electrochemistry as well.This paper explored a new and green method for the preparation of carbon nanostructured materials.The applications of the carbon-based electrocatalysts as electrode materials were explored and the bioelectrochemical properties were investigated as well.This paper studied the dynamic process of regeneration of carbon dots as electrode materials,developed carbon dots-based electrocatalysts with high electrocatalytic activity,explored graphite-carbon nitride as electrode materials achieving a newphotoelectrochemicalcell,and investigated the biological electrochemical properties of fullerenols.The detailed work includes the following parts:1.N-C dots were synthesized through a facile and one-pot photon-assisted biodegradation method using CAT catalyzed degradation C₃N₄ without adding any external agents.This method does not need organic solvent and oxidizing agent.This biodegradation method combines the merits of green,controllable,safe and biocompatible.The N-C dots possess excellent aqueous dispersibility without any surface modifications and strong visible emission.The study confirms that the N-C dots have excellent biocompatibility and nontoxicity.2.Carbon dots have been widely investigated in solar photovoltaic.The regeneration kinetics of CDs at CDs-sensitized TiO₂ electrode was first investigated by SECM approach curves based on the feedback mode.The measurement principles of the CDs regeneration are based on examining the feedback current related to the change of the active species concentration under the active area of an ultramicroelectrode probe with short-circuit condition.In this study,testing the regeneration rate of the sensitizer with a single sensitized electrode,provides some new insight into the methods for analysis of the performance of sensitized metal oxide semiconductor electrodes.3.Because carbon dots（CDs）have excellent properties of photoinduced electron transfer,photoluminescence and electronic storage,gold nanoparticle/carbon dot/SnO₂nanocomposites as photo-electronic catalyst were designed and synthesized for oxygen evolution reaction.The carbon dots were synthesized through electrochemical ablation of graphite.The gold nanoparticle stabilized in the SnO₂-CDs were synthesized by a one-step reduction of HAuCl₄ with CDs.Besides,the best OER electrocatalytic activity of the catalyst was obtained by adjusting the addition amount of CDs and HAuCl₄.The resulting composite displayed excellent OER electrocatalytic activity and good stability.4.We demonstrate a photoelectrochemical cell based on g-C₃N₄ photocatalyst using O₂/H₂O redox couples,fabricated by iron（III）phthalocyaninate[Fe^III（Pc）Cl]mixed with g-C₃N₄ spraying on carbon paper as the cathode and a nickel mesh（Ni mesh）coated with g-C₃N₄ as the anode.This photoelectrochemical cell achieves the open-circuit voltage of 0.91 V under AM 1.5G solar light(1 sun,100 mW·cm^-2)in 0.1M HCl at air atmosphere.The total solar to electric power efficiency of this cell is0.146%.Additionally this cell can generate and store H₂O₂（chemical energy）with electrodes disconnected under light,where water oxidation photocatalytic by g-C₃N₄will occur on both the electrodes.By connecting the electrodes,the cell can be operated as a fuel cell using H₂O₂ as the fuel in the absence of sunlight with the capacity of 351 mC·cm^-2.5.Fullerenols have been shown with low cytotoxicity and widely used in the field of bioelectrochemistry.The effects in HeLa cell membrane permeability caused by the fullerenols with different concentrations were studied by scanning electrochemical microscopy.We demonstrate that fullerenols has very low cytotoxicity,however,it can still have strong effects on the cell membrane permeability.In present of 1×10^-3mg·m L^-1（1 ppm）fullerenols,the cell membrane permeability increase by 26%after 76 min,which is reversible.When fullerenols concentration over 25×10^-3mg·m L^-1（25 ppm）,the change of membrane permeability（increased 19%）is irreversible.