I-Formamide: I-Institute yoPhando icebisa ukwenziwa kwe-Photoreforming ye-PET Plastiki yeNkunkuma ukuze kuveliswe i-Formamide

I-Polyethylene terephthalate (PET), njenge-polyester ebalulekileyo ye-thermoplastic, inemveliso yehlabathi jikelele edlula iitoni ezingama-70 ezigidi kwaye isetyenziswa kakhulu kwiipakethe zokutya zemihla ngemihla, amalaphu, kunye nezinye iindawo. Nangona kunjalo, emva kwalo mthamo mkhulu wemveliso, malunga ne-80% yenkunkuma ye-PET ilahlwa ngokungakhethiyo okanye igcwaliswe emhlabeni, nto leyo ebangela ungcoliseko olukhulu lokusingqongileyo kwaye ikhokelele ekuchithweni kwezixhobo ezinkulu zekhabhoni. Indlela yokufezekisa ukuphinda kusetyenziswe inkunkuma ye-PET ibe ngumngeni obalulekileyo ofuna impumelelo kuphuhliso oluzinzileyo lwehlabathi.

Phakathi kwezobuchwepheshe bokusebenzisa kwakhona obukhoyo, ubuchwepheshe bokuguqula i-photoreforming bufumene ingqwalasela enkulu ngenxa yeempawu zayo eziluhlaza nezithambileyo. Le ndlela isebenzisa amandla elanga acocekileyo, angangcolisiyo njengamandla okuqhuba, ivelisa iintlobo ze-redox ezisebenzayo kwindawo ephantsi kobushushu obuqhelekileyo kunye noxinzelelo ukuze kube lula ukuguqulwa kunye nokuphuculwa kwexabiso leplastiki yenkunkuma. Nangona kunjalo, iimveliso zeenkqubo zangoku zokuguqula i-photoreforming zikhawulelwe kakhulu kwiikhompawundi ezilula eziqulethe i-oxygen ezifana ne-formic acid kunye ne-glycolic acid.

Kutshanje, iqela lophando elivela kwiZiko loGuqulelo lwePhotochemical kunye neSynthesis kwiziko laseTshayina licebise ukusebenzisa inkunkuma yePET kunye ne-ammonia njengemithombo yekhabhoni kunye ne-nitrogen, ngokulandelelana, ukuvelisa i-formamide nge-photocatalytic CN coupling reaction. Ngenxa yesi sizathu, abaphandi bayila i-photocatalyst yePt1Au/TiO2. Kule catalyst, iindawo ze-Pt ezine-atom enye zibamba ngokukhetha ii-electron ezenziwe nge-photo, ngelixa ii-nanoparticles ze-Au zibamba imingxunya eyenziwe nge-photo, nto leyo ephucula kakhulu ukwahlukana kunye nokusebenza kakuhle kokudluliselwa kwee-electron-hole pairs ezenziwe nge-photo, ngaloo ndlela zinyusa umsebenzi we-photocatalytic. Izinga lokuveliswa kwe-formamide lifikelele malunga ne-7.1 mmol gcat⁻¹ h⁻¹. Uvavanyo olufana ne-in-situ infrared spectroscopy kunye ne-electron paramagnetic resonance lutyhile indlela yokusabela elawulwa yi-radical: imingxunya eyenziwe nge-photo i-oxidize i-ethylene glycol kunye ne-ammonia ngaxeshanye, ivelisa ii-aldehyde intermediates kunye ne-amino radicals (·NH₂), ezidlula kwi-CN coupling ukuze ekugqibeleni zenze i-formamide. Lo msebenzi awupheleli nje ekubeni nguvulindlela kwindlela entsha yokuguqulwa kweplastiki yenkunkuma ngexabiso eliphezulu, uphucula uluhlu lweemveliso zokuphucula i-PET, kodwa ukwabonelela ngecebo eliluhlaza, elingabizi kakhulu, nelithembisayo lokwenziwa kwezinto ezibalulekileyo eziqulethe i-nitrogen ezifana namayeza kunye nezibulali-zinambuzane.

Iziphumo zophando ezinxulumene noko zipapashwe kwi-Angewandte Chemie International Edition phantsi kwesihloko esithi “Photocatalytic Formamide Synthesis from Plastic Waste and Ammonia via CN Bond Construction Under Mild Conditions”. Olu phando lufumene inkxaso-mali kwiiprojekthi ezixhaswe yiNational Natural Science Foundation yaseTshayina, iJoint Laboratory Fund for Novel Materials phakathi kweChinese Academy of Sciences kunye neYunivesithi yaseHong Kong, phakathi kwezinye imithombo.