Igraphite yahlulwe yaba yigraphite eyenziweyo kunye negraphite yendalo, indawo eqinisekisiweyo yehlabathi yegraphite yendalo malunga neetoni ezi-2 zeebhiliyoni.
Igraphite yokwenziwa ifunyenwe ngokubola kunye nokunyangwa kobushushu bezinto ezinekhabhoni phantsi koxinzelelo oluqhelekileyo. Olu tshintsho lufuna ukushisa okwaneleyo kunye namandla njengamandla okuqhuba, kwaye isakhiwo esiphazamisekileyo siya kuguqulwa sibe yi-graphite crystal structure.
I-Graphitization ikwingqiqo ebanzi yemathiriyeli yekhabhoni ngaphezulu kwe-2000 ℃ yokulungiswa kobushushu obuphezulu be-carbon athom, nangona kunjalo ezinye izixhobo zekhabhoni kubushushu obuphezulu obungaphezulu kwe-3000 ℃ graphitization, olu hlobo lwemathiriyeli yekhabhoni lwalusaziwa ngokuba "ngamalahle alukhuni", kuba izixhobo zekhabhoni ezilula, indlela yendabuko yegraphitization ibandakanya ubushushu obuphezulu kunye nendlela yoxinzelelo oluphezulu, i-catalytic graphitization, indlela yokubeka umphunga wekhemikhali, njl.
I-Graphitization yindlela esebenzayo yokusetyenziswa kwexabiso eliphezulu okongeziweyo kwezinto zekhabhoni. Emva kophando olubanzi nolunzulu ngabaphengululi, ngokusisiseko ikhulile ngoku. Nangona kunjalo, ezinye izinto ezingathandekiyo zinciphisa ukusetyenziswa kwegraphitization yendabuko kwishishini, ngoko ke yinto engenakuthintelwa yokuphonononga iindlela ezintsha zegraphitization.
Indlela ye-electrolysis yetyuwa enyibilikisiweyo ukususela ngenkulungwane ye-19 yayingaphezu kwenkulungwane yophuhliso, ithiyori yayo esisiseko kunye neendlela ezintsha zihlala zintsha kunye nophuhliso, ngoku ayisekho kuphela kushishino lwesinyithi lwendabuko, ekuqaleni kwenkulungwane yama-21, isinyithi kwi-metallurgical . Inkqubo yetyuwa etyhidiweyo eqinileyo ye-oxide ye-electrolytic yokunciphisa ukulungiswa kwesinyithi esisisiseko sele igxininise ekusebenzeni ngakumbi,
Kutshanje, indlela entsha yokulungiselela imathiriyeli yegraphite nge<em>electrolysis yetyuwa enyibilikisiweyo iye yatsala ingqalelo enkulu.
Ngokusebenzisa i-cathodic polarization kunye ne-electrodeposition, iifom ezimbini ezahlukeneyo zekhabhoni eziluhlaza ziguqulwa zibe yizinto ze-nano-graphite ezinexabiso eliphezulu elongezelelweyo. Xa kuthelekiswa neteknoloji yendabuko ye-graphitization, indlela entsha ye-graphitization ineenzuzo zokushisa okuphantsi kwe-graphitization kunye ne-morphology elawulwayo.
Eli phepha liphonononga inkqubela phambili ye-graphitization nge-electrochemical method, yazisa le teknoloji intsha, ihlalutya iingenelo zayo kunye nokungalunganga, kunye nethemba lophuhliso lwexesha elizayo.
Okokuqala, ityuwa etyhidiweyo ye-electrolytic cathode polarization method
1.1 imathiriyeli ekrwada
Okwangoku, eyona nto iphambili ye-graphite eyenziweyo yinaliti ye-coke kunye ne-pitch coke yeqondo eliphezulu legraphitization, ezizezi yintsalela yeoli kunye netela yamalahle njengesixhobo sokuvelisa izinto ezikumgangatho ophezulu wekhabhoni, kunye ne-porosity ephantsi, isulfure ephantsi, uthuthu oluphantsi. umxholo kunye neenzuzo zegraphitization, emva kokulungiswa kwayo kwigraphite inokumelana kakuhle nempembelelo, amandla aphezulu omatshini, ukumelana nokuphantsi,
Nangona kunjalo, uvimba we-oyile olinganiselweyo kunye namaxabiso e-oyile aguquguqukayo athintele uphuhliso lwayo, ngoko ke ukufuna izinto ezintsha ekrwada kube yingxaki engxamisekileyo ekufuneka isonjululwe.
Iindlela ze-graphitization zemveli zinemida, kwaye iindlela ezahlukeneyo ze-graphitization zisebenzisa imathiriyeli ekrwada eyahlukeneyo. Kuba carbon non-graphitized, iindlela zemveli nzima graphitize kuyo, lo gama ifomula electrochemical of enyibilikisiweyo electrolysis ityuwa iqhekeza umda izinto ekrwada, kwaye ilungele phantse zonke izinto carbon zemveli.
Izinto zekhabhoni zemveli ziquka i-carbon black, i-carbon activated, amalahle, njl., phakathi kwamalahle awona athembisayo. I-inki esekelwe kumalahle ithatha amalahle njenge-precursor kwaye ilungiswe kwiimveliso zegraphite kwiqondo lokushisa eliphezulu emva konyango lwangaphambili.
Kutshanje, eli phepha liphakamisa iindlela ezintsha ze-electrochemical, ezifana ne-Peng, nge-electrolysis yetyuwa etyhidiweyo ayinakwenzeka ukuba i-graphitized carbon black ibe yikristale ephezulu yegraphite, i-electrolysis yeesampulu zegraphite eziqulethe i-petal shape graphite nanometer chips, inommandla othile ophezulu ophezulu, xa isetyenziselwa ibhetri ye-lithium cathode ibonise ukusebenza kakuhle kwe-electrochemical ngaphezu kwegraphite yendalo.
UZhu et al. beka ilahle ephathwayo ekumgangatho ophantsi kwiCaCl2 inkqubo yetyuwa enyibilikisiweyo ye-electrolysis kwi-950 ℃, kwaye yaguqula ngempumelelo amalahle akumgangatho ophantsi abe yigraphite enekristale ephezulu, ebonisa ukusebenza kakuhle komyinge kunye nobomi bomjikelezo omde xa isetyenziswa njenge-anode yebhethri ye-lithium ion. .
Uvavanyo lubonisa ukuba kuyenzeka ukuguqula iindidi ezahlukeneyo zemathiriyeli yekhabhoni yemveli ibe yigraphite ngokusebenzisa i-electrolysis yetyuwa etyhidiweyo, evula indlela entsha yegraphite yokwenziwa yexa elizayo.
1.2 indlela ye
Indlela ye-electrolysis yetyuwa enyibilikisiweyo isebenzisa izinto zekhabhoni njengecathode kwaye iyiguqule ibe yigraphite enekristale ephezulu ngokusebenzisa i-cathodic polarization. Okwangoku, uncwadi olukhoyo lukhankanya ukususwa kwe-oksijini kunye nokuhlelwa kwakhona komgama omde we-athomu ye-carbon kwindlela yokuguqulwa kwe-cathodic polarization.
Ubukho beoksijini kwizinto zekhabhoni buya kuthintela igraphitization kwinqanaba elithile. Kwinkqubo ye-graphitization yendabuko, i-oxygen iya kususwa ngokukhawuleza xa ubushushu buphezulu kune-1600K. Nangona kunjalo, kulula kakhulu ukwenza i-deoxidize ngokusebenzisa i-cathodic polarization.
I-Peng, njl.njl kuvavanyo okokuqala ngqa i-electrolysis etyhidiweyo ye-electrolysis cathodic polarization ye-polarization yenkqubo enokubakho, eyile graphitization eyona ndawo iqalwa kuyo kufuneka ibekwe kwi-carbon microspheres/ujongano lwe-electrolyte, imo yokuqala ye-carbon microsphere ejikeleze ubukhulu obufanayo. iqokobhe legraphite, kwaye emva koko ungaze uzinze iiathom zekhabhoni ye-anhydrous ze-anhydrous zisasazeke kwiflake yegraphite yangaphandle ezinzile, de ibe yigraphiti ngokupheleleyo,
Inkqubo ye-graphitization ihamba kunye nokususwa kwe-oksijini, ekwaqinisekiswa ngovavanyo.
Jin et al. kwakhona yangqina le mbono ngokusebenzisa imifuniselo. Emva kwe-carbonization ye-glucose, i-graphitization (i-17% ye-oxygen content) yenziwa. Emva kwe-graphitization, i-original carbon spheres (Umfanekiso we-1a kunye ne-1c) yenza igobolondo elinobuchwephesha elihlanganiswe ne-graphite nanosheets (Umfanekiso 1b kunye ne-1d).
Nge-electrolysis ye-carbon fibers (i-16% ye-oksijini), i-carbon fibers inokuguqulwa ibe yimibhobho yegraphite emva kwe-graphitization ngokwendlela yokuguqula echazwe kwiincwadi.
Kukholelwa ukuba, intshukumo yomgama omde iphantsi kwe-cathodic polarization yeeathom zekhabhoni igraphite ephezulu yekristale ukuya kwi-amorphous carbon rearrange kufuneka iqhubeke, i-synthetic graphite petals unique shape nanostructures ixhamle kwii-athom ze-oksijini ukusuka, kodwa indlela ethile yokuphembelela i-graphite nanometer isakhiwo akucaci, njengeoksijini evela kwikhabhoni yamathambo emva kwendlela yokusabela kwecathode, njl.,
Okwangoku, uphando malunga nomatshini lusekwinqanaba lokuqala, kwaye uphando olongezelelweyo luyafuneka.
1.3 Ukubonakaliswa kwe-morphological yegraphite yokwenziwa
I-SEM isetyenziselwa ukujonga i-microscopic surface morphology yegraphite, i-TEM isetyenziselwa ukujonga i-morphology yesakhiwo esingaphantsi kwe-0.2 μm, i-XRD kunye ne-Raman spectroscopy zezona zixhobo zisetyenziswa ngokuqhelekileyo ukubonisa i-microstructure yegraphite, i-XRD isetyenziselwa ukubonakalisa ikristale. ulwazi lwegraphite, kunye neRaman spectroscopy isetyenziselwa ukubonakalisa iziphene kunye nomyalelo weqondo legraphite.
Kukho iipores ezininzi kwi-graphite elungiselelwe yi-cathode polarization ye-electrolysis yetyuwa etyhidiweyo. Kwizinto ezahlukeneyo eziluhlaza, ezifana ne-carbon black electrolysis, i-petal-like nanostructures ye-porous ifunyenwe. Uhlalutyo lwe-XRD kunye ne-Raman lwe-spectrum lwenziwa kwi-carbon black emva kwe-electrolysis.
Kwi-827 ℃, emva kokunyangwa nge-voltage ye-2.6V ye-1h, umfanekiso we-Raman we-spectral ye-carbon emnyama uphantse ufana naleyo yegraphite yorhwebo. Emva kokuba i-carbon black iphathwe ngamaqondo okushisa ahlukeneyo, incopho ebukhali yegraphite (002) iyalinganiswa. Incopho ye-diffraction (002) imele iqondo lokuqhelaniswa ne-carbon layer enevumba elimnandi kwigraphite.
I-carbon layer ibukhali ngakumbi, ijolise ngakumbi.
UZhu wasebenzisa amalahle asulungekileyo angaphantsi njengecathode kuvavanyo, kunye ne-microstructure yemveliso yegraphiti yatshintshwa ukusuka kwigranular ukuya kwisakhiwo esikhulu segraphite, kwaye umaleko oqinileyo wegraphite nawo wabonwa phantsi kwe-electronic microscope ephezulu yothumelo.
Kwimbonakalo yeRaman, ngotshintsho lweemeko zovavanyo, ixabiso le-ID/Ig nalo litshintshile. Xa ubushushu be-electrolytic yi-950 ℃, ixesha le-electrolytic laliyi-6h, kwaye i-electrolytic voltage yi-2.6V, ixabiso eliphantsi le-ID / Ig laliyi-0.3, kwaye i-D iphantsi kakhulu kune-G peak. Kwangaxeshanye, ukubonakala kwencopho ye-2D nayo imele ukubunjwa kwesakhiwo segraphite esicwangciswe kakhulu.
I-peak ebukhali (002) ye-diffraction kumfanekiso we-XRD iphinda iqinisekise ukuguqulwa okuphumelelayo kwamalahle angaphantsi kwi-graphite ene-crystallinity ephezulu.
Kwinkqubo yegraphitization, ukunyuka kwamaqondo obushushu kunye nombane kuya kudlala indima yokukhuthaza, kodwa amandla ombane aphezulu kakhulu aya kunciphisa isivuno segraphite, kwaye ubushushu obuphezulu kakhulu okanye ixesha elide legraphitization liya kukhokelela kwinkcitho yemithombo, ngoko ke kwizinto ezahlukeneyo zekhabhoni. , kubaluleke kakhulu ukuphonononga iimeko ezifanelekileyo ze-electrolytic, kwakhona kugxilwe kunye nobunzima.
Le petal-like flake nanostructure ineepropathi ezigqwesileyo ze-electrochemical. Inani elikhulu lee-pores livumela i-ion ukuba ifakwe ngokukhawuleza / ifakwe, inikezela ngezinto eziphezulu ze-cathode kwiibhetri, njl.
Indlela ye-electrodeposition yetyuwa etyhidiweyo
2.1 Electrodeposition of carbon dioxide
Njengeyona gesi yegreenhouse ibalulekileyo, i-CO2 ikwayinto engeyotyhefu, ayinabungozi, ingabizi kwaye ifumaneka lula ubutyebi obuhlaziyekayo. Nangona kunjalo, i-carbon kwi-CO2 ikwimo ephezulu ye-oxidation, ngoko ke i-CO2 inozinzo oluphezulu lwe-thermodynamic, eyenza kube nzima ukuphinda isetyenziswe.
Uphando lokuqala kwi-CO2 electrodeposition inokulandelwa emva kwe-1960s. Ingram et al. ilungiswe ngempumelelo ikhabhoni kwi-electrode yegolide kwinkqubo yetyuwa etyhidiweyo ye-Li2CO3-Na2CO3-K2CO3.
Van et al. ibonise ukuba i-carbon powders efunyenwe kwiinkalo ezahlukeneyo zokunciphisa zinezakhiwo ezahlukeneyo, kuquka igraphite, i-amorphous carbon kunye ne-carbon nanofibers.
Ngetyuwa etyhidiweyo ukubamba i-CO2 kunye nendlela yokulungiselela impumelelo yezinto zekhabhoni, emva kwexesha elide lophando lwabaphengululi baye bagxila kwi-carbon deposition formation mechanism kunye nefuthe leemeko ze-electrolysis kwimveliso yokugqibela, equka ubushushu be-electrolytic, i-electrolytic voltage kunye nokwakhiwa ityuwa etyhidiweyo kunye ne-electrodes, njl., ukulungiswa kokusebenza okuphezulu kwezinto zegraphite kwi-electrodeposition ye-CO2 ibeke isiseko esiqinileyo.
Ngokuguqula i-electrolyte kunye nokusebenzisa inkqubo yetyuwa etyhidiweyo ye-CaCl2 ene-CO2 ephezulu yokubamba ukusebenza kakuhle, u-Hu et al. ilungiswe ngempumelelo igraphene eneqondo eliphezulu legraphitization kunye necarbon nanotubes kunye nezinye izakhiwo ze-nanographite ngokufunda iimeko ze-electrolytic ezifana nobushushu be-electrolysis, ukubunjwa kwe-electrode kunye nokubunjwa kwetyuwa etyhidiweyo.
Xa kuthelekiswa nenkqubo ye-carbonate, i-CaCl2 ineenzuzo zexabiso eliphantsi kwaye kulula ukuyifumana, i-conductivity ephezulu, ilula ukuyinyibilika emanzini, kunye ne-solubility ephezulu yeeoni ze-oxygen, ezibonelela ngeemeko zethiyori zokuguqulwa kwe-CO2 kwiimveliso zegraphite ezinexabiso eliphezulu elongezelelweyo.
2.2 Inkqubo yoTshintsho
Ukulungiswa kwexabiso eliphezulu lezinto zekhabhoni nge-electrodeposition ye-CO2 evela kwityuwa etyhidiweyo ikakhulukazi iquka ukubamba i-CO2 kunye nokunciphisa ngokungathanga ngqo. Ukubanjwa kwe-CO2 kugqityezelwa nge-O2 yasimahla kwityuwa etyhidiweyo, njengoko kubonisiwe kwi-Equation (1):
CO2+O2-→CO3 2- (1)
Okwangoku, iindlela ezintathu zokusabela zokunciphisa ngokungathanga ngqo ziye zacetywa: ukusabela kwenyathelo elinye, ukusabela ngamanyathelo amabini kunye nesixhobo sokunciphisa isinyithi.
Indlela yokusabela yenyathelo elinye yacetywa kuqala ngu-Ingram, njengoko kubonisiwe kwi-Equation (2):
CO3 2-+ 4E – →C+3O2- (2)
Indlela yokusabela ngamanyathelo amabini yacetywa nguBorucka et al., njengoko kubonisiwe kwi-Equation (3-4):
CO3 2-+ 2E – →CO2 2-+O2- (3)
CO2 2-+ 2E – →C+2O2- (4)
Indlela yokusabela yokunciphisa isinyithi yacetywa nguDeanhardt et al. Babekholelwa ukuba i-ion zentsimbi zaqale zancitshiswa zibe yintsimbi kwi-cathode, emva koko isinyithi sancitshiswa saba yi-carbonate ion, njengoko kubonisiwe kwi-Equation (5~6):
M- + E – →M (5)
4 m + M2CO3 – > C + 3 m2o (6)
Okwangoku, indlela yokusabela inyathelo elinye iyamkelwa ngokubanzi kuncwadi olukhoyo.
Yin et al. wafunda inkqubo ye-carbonate ye-Li-Na-K ene-nickel njenge-cathode, i-tin dioxide njenge-anode kunye nocingo lwesilivere njenge-electrode yereferensi, kwaye yafumana umzobo we-cyclic voltammetry wovavanyo kuMfanekiso 2 (umlinganiselo wokuskena we-100 mV/s) kwi-nickel cathode, kwaye yafunyanwa. ukuba bekukho incopho enye kuphela yokunciphisa (e--2.0V) kuskena olubi.
Ngoko ke, kunokugqitywa ukuba enye kuphela impendulo eyenzekayo ngexesha lokunciphisa i-carbonate.
Gao et al. ifumene i-voltammetry ye-cyclic efanayo kwi-carbonate system efanayo.
Fumana et al. isebenzise i-anode ye-inert kunye ne-tungsten cathode ukubamba i-CO2 kwinkqubo ye-LiCl-Li2CO3 kwaye yafumana imifanekiso efanayo, kwaye kuphela incopho yokunciphisa i-carbon deposition ibonakala kwi-scanning engalunganga.
Kwinkqubo ye-alkaline yesinyithi etyhidiweyo yetyuwa, isinyithi se-alkali kunye ne-CO ziya kuveliswa ngelixa i-carbon ifakwe yi-cathode. Nangona kunjalo, ngenxa yokuba iimeko ze-thermodynamic ze-carbon deposition reaction ziphantsi kwiqondo lokushisa eliphantsi, kuphela ukucutha kwe-carbonate kwi-carbon kunokubonwa kuvavanyo.
2.3 I-CO2 ibamba ngetyuwa etyhidiweyo ukulungiselela iimveliso zegraphite
Ixabiso eliphezulu elongeziweyo le-graphite nanomatadium ezifana negraphene kunye ne-carbon nanotubes zinokulungiswa nge-electrodeposition ye-CO2 esuka kwityuwa etyhidiweyo ngokulawula iimeko zokulinga. Hu et al. isetyenziswe insimbi engenasici njenge-cathode kwinkqubo yetyuwa etyhidiweyo ye-CaCl2-NaCl-CaO kunye ne-electrolyzed ye-4h phantsi kwemeko ye-2.6V yombane rhoqo kumaqondo okushisa ahlukeneyo.
Ngombulelo kwi-catalysis yentsimbi kunye nefuthe eliqhumayo le-CO phakathi kweeleyile zegraphite, igraphene yafunyanwa kumphezulu we-cathode. Inkqubo yokulungiselela igraphene iboniswe kumfanekiso wesi-3.
Umfanekiso
Uphononongo kamva longeze i-Li2SO4 ngesiseko senkqubo yetyuwa etyhidiweyo yeCaCl2-NaClCaO, ubushushu be-electrolysis yayingu-625 ℃, emva kwe-4h ye-electrolysis, ngexesha elifanayo kwi-cathodic deposition ye-carbon efunyenwe igraphene kunye ne-carbon nanotubes, uphando lufumene ukuba i-Li + kunye ne-SO4 2 - ukuzisa isiphumo esihle kwigraphitization.
I-sulfure iphinda ihlanganiswe ngempumelelo kumzimba wekhabhoni, kwaye i-ultra-thin graphite sheets kunye ne-filamentous carbon ingafumaneka ngokulawula iimeko ze-electrolytic.
Izinto ezifana nobushushu be-electrolytic obuphezulu naphantsi kukwenziwa kwegraphene bubalulekile, xa iqondo lobushushu lingaphezulu kwama-800 ℃ kulula ukuvelisa iCO endaweni yekhabhoni, phantse akukho kubekwa kwekhabhoni xa kungaphezulu kwama-950 ℃, ngoko ke ulawulo lobushushu lubaluleke kakhulu. ukuvelisa i-graphene kunye ne-carbon nanotubes, kunye nokubuyisela imfuno ye-carbon deposition reaction reaction ye-CO reaction synergy ukuqinisekisa ukuba i-cathode ukuvelisa i-graphene ezinzileyo.
Le misebenzi ibonelela ngendlela entsha yokulungiswa kweemveliso ze-nano-graphite nge-CO2, eyona nto ibaluleke kakhulu kwisisombululo se-greenhouse gases kunye nokulungiswa kwegraphene.
3. Isishwankathelo kunye ne-Outlook
Ngophuhliso olukhawulezayo lweshishini elitsha lamandla, igraphite yendalo ayikwazanga ukuhlangabezana nemfuno yangoku, kwaye igraphite eyenziweyo ineempawu ezingcono zomzimba kunye neekhemikhali kunegraphite yendalo, ngoko ke igraphitization eshibhile, esebenzayo kunye nokusingqongileyo yinjongo yexesha elide.
Iindlela ze-electrochemical graphitization kwizinto eziqinileyo kunye negesi ekrwada kunye nendlela ye-cathodic polarization kunye ne-electrochemical deposition iphume ngempumelelo kwizinto zegraphite ezinexabiso eliphezulu elongezelelweyo, xa kuthelekiswa nendlela yendabuko yegraphitization, indlela ye-electrochemical iyasebenza kakhulu, ukusetyenziswa kwamandla aphantsi, ukukhuselwa kokusingqongileyo okuluhlaza, kuncinci okulinganiselwe ngezinto ezikhethiweyo ngaxeshanye, ngokweemeko ezahlukeneyo ze-electrolysis zinokulungiswa kwi-morphology eyahlukeneyo yesakhiwo segraphite,
Inika indlela esebenzayo kuzo zonke iintlobo zekhabhoni ye-amorphous kunye ne-greenhouse gases ukuba iguqulelwe kwizinto ezixabisekileyo ze-nano-structured graphite kwaye inethemba elihle lokusebenzisa.
Okwangoku, le teknoloji ikwindawo yokuqala. Kukho izifundo ezimbalwa kwi-graphitization nge-electrochemical method, kwaye kusekho iinkqubo ezininzi ezingaziwa. Ngoko ke, kuyimfuneko ukuqala kwizinto eziluhlaza kwaye uqhube uphando olubanzi kunye nolucwangcisiweyo kwiikhabhoni ezahlukeneyo ze-amorphous, kwaye kwangaxeshanye uphonononge i-thermodynamics kunye ne-dynamics yokuguqulwa kwegraphite kwinqanaba elinzulu.
Ezi zinokubaluleka okude kuphuhliso lwekamva loshishino lwegraphite.
Ixesha lokuposa: May-10-2021