Graphite ya kasu kashi-kashi na graphite na wucin gadi da graphite na halitta, tabbataccen tanadin graphite na halitta a cikin kusan tan biliyan biyu.
Ana samun graphite na wucin gadi ta hanyar lalatawa da maganin zafi na kayan da ke ɗauke da carbon a ƙarƙashin matsin lamba na al'ada.Wannan canji yana buƙatar isasshen zafin jiki da kuzari a matsayin ƙarfin tuƙi, kuma tsarin da ba daidai ba zai zama tsarin kristal da aka ba da oda.
Graphitization ne a cikin widest ma'ana na carbonaceous abu ta hanyar sama 2000 ℃ high zafin jiki zafi magani carbon atom sake tsarawa, duk da haka wasu carbon kayan a cikin high zafin jiki sama da 3000 ℃ graphitization, irin wannan carbon kayan da aka sani da "hard gawayi", domin sauƙin graphitized carbon kayan, da gargajiya graphitization hanya sun hada da high zafin jiki da kuma high matsa lamba Hanyar, catalytic graphitization, sinadaran tururi ajiya hanya, da dai sauransu.
Zane-zanen hoto hanya ce mai inganci ta ƙarin ƙimar amfani da kayan carbonaceous.Bayan bincike mai zurfi da zurfin bincike da masana suka yi, yanzu ya balaga.Duk da haka, wasu abubuwan da ba su da kyau suna iyakance aikace-aikacen graphitization na gargajiya a cikin masana'antu, don haka yanayi ne da ba makawa don gano sababbin hanyoyin graphitization.
Hanyar narkakken gishirin electrolysis tun daga karni na 19 ya fi karni na ci gaba, ka'idarsa ta asali da sabbin hanyoyin da ake ci gaba da ingantawa da ci gaba, yanzu ba a iyakance ga masana'antar karafa na gargajiya ba, a farkon karni na 21, karfe da narkakken gishiri tsarin m oxide electrolytic rage shirye-shirye na elemental karafa sun zama mayar da hankali a cikin mafi aiki,
Kwanan nan, wata sabuwar hanyar shirya kayan graphite ta narkakkar wutar lantarki ta gishiri ta ja hankali sosai.
Ta hanyar katodic polarization da electrodeposition, nau'ikan nau'ikan albarkatun carbon guda biyu daban-daban ana canza su zuwa kayan nano-graphite tare da ƙarin ƙima.Idan aka kwatanta da fasahar graphitization na al'ada, sabuwar hanyar graphitization tana da fa'idodin ƙananan zafin jiki na graphitization da ilimin halittar jiki mai sarrafawa.
Wannan takarda tana nazarin ci gaban graphitization ta hanyar hanyar lantarki, gabatar da wannan sabuwar fasaha, tana nazarin fa'idodinta da rashin amfaninta, da kuma fatan yanayin ci gabanta na gaba.
Na farko, narkar da gishiri electrolytic cathode polarization hanya
1.1 albarkatun kasa
A halin yanzu, babban albarkatun kasa na wucin gadi graphite ne allura coke da farar coke na high graphitization digiri, wato ta mai saura da kuma kwal kwal a matsayin albarkatun kasa don samar da wani high quality-carbon kayan, tare da low porosity, low sulfur, low ash. abun ciki da kuma abũbuwan amfãni na graphitization, bayan da shiri a cikin graphite yana da kyau juriya ga tasiri, high inji ƙarfi, low resistivity,
Sai dai kuma, karancin man fetur da kuma hauhawar farashin man sun takaita ci gabansa, don haka neman sabbin albarkatun kasa ya zama matsala cikin gaggawa da za a magance.
Hanyoyin graphitization na al'ada suna da iyakancewa, kuma hanyoyin graphitization daban-daban suna amfani da albarkatun ƙasa daban-daban.Ga carbon da ba a graphitized ba, hanyoyin gargajiya da kyar ba za su iya zayyana shi ba, yayin da dabarar electrochemical na narkakken gishiri electrolysis ke karya ta iyakance albarkatun ƙasa, kuma ya dace da kusan duk kayan carbon na gargajiya.
Abubuwan carbon na gargajiya sun haɗa da carbon baƙar fata, carbon da aka kunna, kwal, da dai sauransu, daga cikinsu kwal ɗin shine mafi alƙawari.Tawada mai tushen kwal yana ɗaukar gawayi azaman mafari kuma an shirya shi cikin samfuran graphite a babban zafin jiki bayan riga-kafi.
Kwanan nan, wannan takarda ya ba da shawarar sabon hanyoyin electrochemical, kamar Peng, ta zurfafan gishiri electrolysis ba shi yiwuwa a graphitized carbon baki a cikin babban crystallinity na graphite, da electrolysis na graphite samfurori dauke da petal siffar graphite nanometer kwakwalwan kwamfuta, yana da high takamaiman surface area. lokacin amfani da lithium baturi cathode ya nuna kyakkyawan aikin electrochemical fiye da graphite na halitta.
Zhu et al.sanya Deashing bi da low quality-coal cikin CaCl2 narkakken gishiri tsarin ga electrolysis a 950 ℃, da kuma samu nasarar canza low quality-coal zuwa graphite tare da high crystallinity, wanda ya nuna mai kyau kudi yi da kuma dogon sake zagayowar rayuwa lokacin amfani da matsayin anode na lithium ion baturi. .
Gwajin ya nuna cewa yana yiwuwa a canza nau'ikan nau'ikan kayan carbon na gargajiya zuwa graphite ta hanyar narkakken gishirin lantarki, wanda ke buɗe wata sabuwar hanya ta graphite na roba a nan gaba.
1.2 tsarin
Hanyar electrolysis gishiri narke yana amfani da kayan carbon azaman cathode kuma yana canza shi zuwa graphite tare da babban crystallinity ta hanyar polarization cathodic.A halin yanzu, wallafe-wallafen da ke akwai suna ambaton kau da iskar oxygen da kuma sake tsara nisa na atom ɗin carbon a cikin yuwuwar tsarin jujjuyawar katodic polarization.
Kasancewar iskar oxygen a cikin kayan carbon zai hana graphitization zuwa wani matsayi.A cikin tsarin zane na gargajiya, za a cire oxygen a hankali lokacin da zafin jiki ya fi 1600K.Koyaya, yana da matukar dacewa don deoxidize ta hanyar polarization na cathodic.
Peng, da sauransu a cikin gwaje-gwajen a karon farko sun gabatar da narkakkar gishiri electrolysis cathodic polarization m inji, wato graphitization mafi wurin da za a fara shi ne ya kasance a cikin m carbon microspheres / electrolyte dubawa, na farko carbon microsphere form a kusa da asali guda diamita. graphite harsashi, sa'an nan kuma taba barga anhydrous carbon carbon atom yada zuwa mafi barga m graphite flake, har sai gaba daya graphitized,
Tsarin graphitization yana tare da kawar da iskar oxygen, wanda kuma an tabbatar da shi ta hanyar gwaje-gwaje.
Jin et al.Hakanan ya tabbatar da wannan ra'ayi ta hanyar gwaje-gwaje.Bayan carbonization na glucose, graphitization (17% oxygen abun ciki) da aka gudanar.Bayan graphitization, asali m carbon spheres (Fig. 1a da 1c) kafa porous harsashi hada da graphite nanosheets (Fig. 1b da 1d).
Ta hanyar electrolysis na carbon fibers (16% oxygen), za'a iya canza filayen carbon zuwa bututun graphite bayan graphitization bisa ga tsarin jujjuyawar da aka yi hasashe a cikin adabi.
An yi imani da cewa, da dogon nisa motsi ne a karkashin cathodic polarization na carbon atom da high crystal graphite zuwa amorphous carbon sake tsarawa dole ne aiwatar, roba graphite musamman petals siffar nanostructures amfana daga oxygen atom daga, amma takamaiman yadda za a tasiri graphite nanometer tsarin bai bayyana. kamar oxygen daga carbon kwarangwal bayan yadda a cathode dauki, da dai sauransu.
A halin yanzu, bincike kan tsarin yana kan matakin farko, kuma ana buƙatar ƙarin bincike.
1.3 Halayen ilimin dabi'a na graphite na roba
Ana amfani da SEM don lura da ƙananan ƙwayoyin cuta na graphite, ana amfani da TEM don lura da tsarin tsarin halittar ƙasa da 0.2 μm, XRD da Raman spectroscopy sune mafi yawan hanyoyin da ake amfani da su don siffanta microstructure na graphite, ana amfani da XRD don kwatanta crystal. bayanai na graphite, kuma Raman spectroscopy ana amfani dashi don siffanta lahani da oda digiri na graphite.
Akwai pores da yawa a cikin graphite wanda aka shirya ta hanyar cathode polarization na narkakken gishirin lantarki.Don albarkatun kasa daban-daban, irin su carbon black electrolysis, ana samun nanostructures masu kama da petal.XRD da Raman binciken bakan ana yin su akan baƙin carbon bayan electrolysis.
A 827 ℃, bayan an bi da shi tare da ƙarfin lantarki na 2.6V na 1h, hoton Raman na baƙar fata na carbon kusan iri ɗaya ne da na graphite na kasuwanci.Bayan an yi maganin baƙar carbon ɗin tare da yanayin zafi daban-daban, ana auna ƙimar sifa mai kaifi (002).Kololuwar rarrabuwar kawuna (002) tana wakiltar matakin daidaitawar Layer carbon aromatic a cikin graphite.
Da kaifi da kaifi Layer ne, da karin daidaitacce shi ne.
Zhu ya yi amfani da kwal ɗin da aka tsarkake a matsayin cathode a cikin gwajin, kuma ƙirar ƙirar samfurin da aka zayyana an canza shi daga granular zuwa babban tsarin graphite, kuma an kuma lura da madaidaicin faifan graphite a ƙarƙashin babban ma'aunin lantarki mai saurin watsawa.
A cikin Raman Spectra, tare da canjin yanayin gwaji, ƙimar ID/Ig kuma ta canza.Lokacin da zafin jiki na electrolytic ya kasance 950 ℃, lokacin electrolytic shine 6h, kuma ƙarfin lantarki shine 2.6V, ƙimar ID / Ig mafi ƙasƙanci shine 0.3, kuma mafi girman D ya kasance ƙasa da G kololuwa.A lokaci guda, bayyanar kololuwar 2D shima yana wakiltar samuwar tsarin zane mai girma da aka ba da oda.
Kololuwar juzu'i mai kaifi (002) a cikin hoton XRD kuma yana tabbatar da nasarar jujjuyawar ƙarancin gawayi zuwa graphite tare da babban crystallinity.
A cikin tsarin graphitization, haɓakar zafin jiki da ƙarfin lantarki za su taka rawar haɓakawa, amma babban ƙarfin lantarki zai rage yawan amfanin graphite, kuma yawan zafin jiki ko tsayin lokaci mai tsayi zai haifar da ɓarnawar albarkatu, don haka ga kayan aikin carbon daban-daban. , yana da mahimmanci musamman don bincika yanayin da ya fi dacewa da yanayin electrolytic, shine ma mai da hankali da wahala.
Wannan petal-kamar flake nanostructure yana da kyawawan kaddarorin electrochemical.Yawancin pores suna ba da damar ions da sauri da za a saka su / sakawa, samar da kayan aikin cathode masu inganci don batura, da dai sauransu. Saboda haka, hanyar graphitization na electrochemical shine hanya mai mahimmanci na graphitization.
Hanyar narkar da gishirin lantarki
2.1 Electrodeposition na carbon dioxide
A matsayin mafi mahimmancin iskar gas, CO2 shima ba mai guba bane, mara lahani, mai arha kuma mai sauƙin samun albarkatu.Duk da haka, carbon a cikin CO2 yana cikin mafi girman yanayin iskar shaka, don haka CO2 yana da kwanciyar hankali mai girma, wanda ya sa ya yi wuya a sake amfani da shi.
Binciken farko akan CO2 electrodeposition za a iya gano shi tun shekarun 1960.Ingram et al.samu nasarar shirya carbon akan lantarki na gwal a cikin narkakken gishirin tsarin Li2CO3-Na2CO3-K2CO3.
Van et al.ya nuna cewa foda na carbon da aka samu a nau'ikan raguwa daban-daban suna da sifofi daban-daban, gami da graphite, carbon amorphous da carbon nanofibers.
Ta hanyar zurfafan gishiri don kama CO2 da hanyar shirye-shiryen nasarar kayan aikin carbon, bayan dogon lokaci na masana bincike sun mai da hankali kan tsarin samar da iskar carbon da tasirin yanayin electrolysis akan samfurin ƙarshe, wanda ya haɗa da zafin jiki na electrolytic, ƙarfin lantarki na lantarki da abun da ke ciki. narkakkar gishiri da lantarki, da dai sauransu, da shirye-shiryen na high yi na graphite kayan for electrodeposition na CO2 ya aza m harsashi.
Ta hanyar canza electrolyte da amfani da tsarin gishiri na tushen CaCl2 tare da mafi girman ingancin kama CO2, Hu et al.samu nasarar shirya graphene tare da mafi girma graphitization digiri da carbon nanotubes da sauran nanographite Tsarin ta nazarin electrolytic yanayi kamar electrolysis zafin jiki, electrode abun da ke ciki da narkakkar gishiri abun da ke ciki.
Idan aka kwatanta da tsarin carbonate, CaCl2 yana da abũbuwan amfãni na arha da sauƙi don samun, high conductivity, mai sauƙi narke cikin ruwa, da kuma mafi girma solubility na oxygen ions, wanda ya samar da ka'idar yanayi don tuba na CO2 cikin graphite kayayyakin da high kara darajar.
2.2 Tsarin Canji
Shirye-shiryen abubuwan da aka ƙara darajar carbon ta hanyar electrodeposition na CO2 daga narkakken gishiri ya haɗa da kama CO2 da raguwa kai tsaye.An kammala kama CO2 ta O2- a cikin narkakken gishiri kyauta, kamar yadda aka nuna a cikin Equation (1):
CO2+O2-→CO3 2- (1)
A halin yanzu, an ba da shawarar hanyoyin rage kaikaice guda uku: amsa mataki ɗaya, matakin mataki biyu da injin rage ɗaukar ƙarfe.
Ingram ne ya fara gabatar da tsarin amsawa ta mataki ɗaya, kamar yadda aka nuna a cikin Equation (2):
CO3 2-+ 4E – →C+3O2- (2)
Borucka et al., ya gabatar da tsarin amsawa ta mataki biyu, kamar yadda aka nuna a cikin Equation (3-4):
CO3 2-+ 2E – →CO2 2-+O2- (3)
CO2 2-+ 2E - →C+2O2- (4)
Deanhardt et al ne ya gabatar da tsarin rage ƙarfin ƙarfe.Sun yi imanin cewa an fara rage ions ƙarfe zuwa ƙarfe a cikin cathode, sannan aka rage ƙarfe zuwa ions carbonate, kamar yadda aka nuna a cikin Equation (5 ~ 6):
M- + E – →M (5)
4 m + M2CO3 -> C + 3 m2o (6)
A halin yanzu, tsarin mayar da martani na mataki ɗaya gabaɗaya ana karɓa a cikin adabin da ke akwai.
Yin et al.yayi nazarin tsarin carbonate na Li-Na-K tare da nickel kamar cathode, tin dioxide azaman anode da waya ta azurfa azaman lantarki, kuma ya sami adadi na gwajin voltammetry na cyclic a cikin Hoto 2 (nauyin bincike na 100 mV / s) a nickel cathode, kuma an samo shi. cewa an sami raguwar kololuwa ɗaya kawai (a -2.0V) a cikin binciken mara kyau.
Sabili da haka, ana iya ƙaddamar da cewa amsa ɗaya kawai ya faru a lokacin raguwar carbonate.
Gao et al.samu irin wannan cyclic voltammetry a cikin wannan carbonate tsarin.
Ge et al.An yi amfani da anode inert da tungsten cathode don kama CO2 a cikin tsarin LiCl-Li2CO3 kuma sun sami irin wannan hotuna, kuma kawai raguwar ƙuruciyar ƙarancin carbon ya bayyana a cikin mummunan binciken.
A cikin tsarin gishiri narkar da ƙarfe na alkaline, za a samar da karafa na alkali da CO yayin da cathode ke ajiye carbon.Duk da haka, saboda yanayin yanayin zafi na yanayin ajiyar carbon yana da ƙasa a ƙananan zafin jiki, kawai ragewar carbonate zuwa carbon za a iya ganowa a cikin gwaji.
2.3 CO2 kama ta narkakken gishiri don shirya samfuran graphite
Za'a iya shirya manyan abubuwan da aka ƙara graphite nanomaterials kamar graphene da carbon nanotubes ta hanyar electrodeposition na CO2 daga narkakken gishiri ta hanyar sarrafa yanayin gwaji.Hu et al.An yi amfani da bakin karfe azaman cathode a cikin tsarin gishiri na CaCl2-NaCl-CaO kuma ana amfani da shi don 4h a ƙarƙashin yanayin ƙarfin wutar lantarki na 2.6V akai-akai a yanayin zafi daban-daban.
Godiya ga catalysis na baƙin ƙarfe da tasirin fashewar CO tsakanin graphite yadudduka, an sami graphene a saman cathode.Ana nuna tsarin shirye-shiryen graphene a cikin siffa 3.
Hoton
Daga baya binciken kara Li2SO4 a kan tushen CaCl2-NaClCaO narke gishiri tsarin, electrolysis zafin jiki ne 625 ℃, bayan 4h na electrolysis, a lokaci guda a cikin cathodic jijiya na carbon samu graphene da carbon nanotubes, binciken ya gano cewa Li + da SO4 2 - don kawo sakamako mai kyau akan graphitization.
Sulfur kuma an samu nasarar haɗa shi cikin jikin carbon, kuma ana iya samun zanen zanen hoto mai kauri da filamentous carbon ta hanyar sarrafa yanayin electrolytic.
Material irin su electrolytic zafin jiki na high da low don samuwar graphene yana da mahimmanci, lokacin da zafin jiki sama da 800 ℃ ya fi sauƙi don samar da CO maimakon carbon, kusan babu ajiyar carbon lokacin da ya fi 950 ℃, don haka kula da zafin jiki yana da mahimmanci. don samar da graphene da carbon nanotubes, da kuma mayar da bukatar carbon ajiya dauki CO dauki synergy don tabbatar da cewa cathode don samar da barga graphene.
Wadannan ayyuka suna ba da sabuwar hanya don shirye-shiryen nano-graphite samfurori ta CO2, wanda ke da mahimmanci ga maganin gas da kuma shirye-shiryen graphene.
3. Summary da Outlook
Tare da saurin haɓaka sabbin masana'antar makamashi, graphite na halitta ya kasa biyan buƙatu na yanzu, kuma graphite na wucin gadi yana da mafi kyawun kaddarorin jiki da sinadarai fiye da graphite na halitta, don haka arha, inganci da ƙirar ƙirar muhalli shine burin dogon lokaci.
Electrochemical hanyoyin graphitization a cikin m da gaseous albarkatun kasa tare da Hanyar cathodic polarization da electrochemical jijiya da aka samu nasarar fita daga cikin graphite kayan da high kara darajar, idan aka kwatanta da gargajiya hanyar graphitization, da electrochemical Hanyar ne na mafi girma yadda ya dace, m makamashi amfani. kore muhalli kariya, ga kananan iyakance ta zabi kayan a lokaci guda, bisa ga daban-daban electrolysis yanayi za a iya shirya a daban-daban ilimin halittar jiki na graphite tsarin,
Yana ba da ingantacciyar hanya don kowane nau'in carbon amorphous da iskar gas don juyar da su zuwa kayan aikin graphite mai mahimmanci na Nano kuma yana da kyakkyawan fata na aikace-aikacen.
A halin yanzu, wannan fasaha tana cikin ƙuruciyarta.Akwai ƴan karatu kan graphitization ta hanyar electrochemical, kuma har yanzu akwai matakai da yawa da ba a sani ba.Saboda haka, wajibi ne a fara daga albarkatun kasa da kuma gudanar da bincike mai zurfi da tsari akan nau'in carbon amorphous daban-daban, kuma a lokaci guda bincika ma'aunin thermodynamics da yanayin jujjuyawar graphite a cikin matakin zurfi.
Waɗannan suna da mahimmanci mai nisa don ci gaban masana'antar graphite na gaba.
Lokacin aikawa: Mayu-10-2021