Peb siv cov ncuav qab zib los txhim kho koj qhov kev paub. Los ntawm kev txuas ntxiv mus saib lub vev xaib no, koj pom zoo rau peb siv cov ncuav qab zib. Xav paub ntxiv.
Cov kab lus no tsom mus rau cov dej acidity ntawm cov oxide catalysts thiab kev txhawb nqa (γ-Al2O3, CeO2, ZrO2, SiO2, TiO2, HZSM5 zeolite) thiab kev sib piv ntawm lawv qhov chaw los ntawm kev ntsuas qhov kub thiab txias-programmed ammonia desorption (ATPD). ATPD yog ib txoj kev txhim khu kev qha thiab yooj yim nyob rau hauv qhov chaw, tom qab tau saturated nrog ammonia ntawm qhov kub thiab txias, undergoes ib tug kub hloov, uas ua rau desorption ntawm sojntsuam molecules raws li zoo raws li kub tis.
Los ntawm qhov ntau thiab / lossis kev txheeb xyuas zoo ntawm tus qauv desorption, cov ntaub ntawv tuaj yeem tau txais ntawm lub zog ntawm desorption / adsorption thiab tus nqi ntawm ammonia adsorbed rau saum npoo (ammonia uptake). Raws li qhov yooj yim molecule, ammonia tuaj yeem siv los ua kev sojntsuam los txiav txim siab acidity ntawm qhov chaw. Cov ntaub ntawv no tuaj yeem pab kom nkag siab txog tus cwj pwm catalytic ntawm cov qauv thiab txawm tias pab kho qhov kev sib txuas ntawm cov tshuab tshiab. Hloov chaw ntawm kev siv ib txwm siv TCD detector, quadrupole mass spectrometer (Hiden HPR-20 QIC) tau siv rau hauv txoj haujlwm, txuas nrog cov cuab yeej ntsuas los ntawm cov cua sov capillary.
Kev siv QMS tso cai rau peb kom yooj yim paub qhov txawv ntawm ntau hom desorbed los ntawm qhov chaw yam tsis muaj kev siv tshuaj lom neeg lossis lub cev lim dej thiab cov ntxiab uas tuaj yeem cuam tshuam rau kev tsom xam. Kev teeb tsa kom zoo ntawm lub cuab yeej ionization muaj peev xwm pab tiv thaiv kev tawg ntawm cov dej molecules thiab ua rau cuam tshuam nrog ammonia m / z teeb liab. Qhov tseeb thiab kev ntseeg siab ntawm cov ntaub ntawv kub-programmed ammonia desorption cov ntaub ntawv tau txheeb xyuas siv cov qauv theoretical thiab kev sim, qhia txog cov teebmeem ntawm cov ntaub ntawv sau hom, cov roj nqa khoom, qhov loj me, thiab cov reactor geometry, ua kom pom qhov yooj ntawm txoj kev siv.
Tag nrho cov ntaub ntawv kawm muaj txoj hauv kev ATPD hom hla 423-873K ntau yam, nrog rau kev zam ntawm cerium, uas nthuav tawm daws qhov nqaim desorption peaks qhia tias tsis tshua muaj acidity. Quantitative cov ntaub ntawv qhia qhov sib txawv ntawm ammonia uptake ntawm lwm yam ntaub ntawv thiab silica los ntawm ntau tshaj li qhov kev txiav txim ntawm magnitude. Txij li thaum ATPD kev faib tawm ntawm cerium ua raws li Gaussian nkhaus tsis hais txog ntawm qhov chaw npog thiab cua sov, tus cwj pwm ntawm cov khoom siv hauv kev kawm tau piav qhia raws li qhov sib txawv ntawm plaub Gaussian lub luag haujlwm cuam tshuam nrog kev sib xyaw ua ke ntawm nruab nrab, tsis muaj zog, muaj zog, thiab cov chaw muaj zog heev. . Thaum tag nrho cov ntaub ntawv tau sau tseg, ATPD qauv kev tshuaj xyuas tau siv los pab kom tau txais cov ntaub ntawv ntawm lub zog adsorption ntawm cov tshuaj ntsuam xyuas molecule raws li kev ua haujlwm ntawm txhua qhov desorption kub. Kev faib hluav taws xob sib txuas los ntawm qhov chaw qhia txog cov txiaj ntsig acidity hauv qab no raws li qhov nruab nrab ntawm lub zog muaj nuj nqis (hauv kJ / mol) (xws li qhov chaw npog θ = 0.5).
Raws li kev sojntsuam cov tshuaj tiv thaiv, propene tau raug lub cev qhuav dej ntawm isopropanol kom tau txais cov ntaub ntawv ntxiv txog kev ua haujlwm ntawm cov ntaub ntawv hauv kev kawm. Cov txiaj ntsig tau txais tau zoo ib yam nrog kev ntsuas ATPD yav dhau los hais txog lub zog thiab kev nplua nuj ntawm qhov chaw acid acid, thiab tseem ua rau nws muaj peev xwm paub qhov txawv ntawm Brønsted thiab Lewis acid sites.
Daim duab 1. (Sab laug) Deconvolution ntawm ATPD profile siv Gaussian muaj nuj nqi (daj dotted kab sawv cev rau generated profile, dub dots yog cov ntaub ntawv sim) (txoj cai) Ammonia desorption zog faib muaj nuj nqi ntawm ntau qhov chaw.
Roberto Di Cio Kws qhia ntawv ntawm Engineering, University of Messina, Contrada Dee Dee, Sant'Agata, I-98166 Messina, Ltalis
Francesco Arena, Roberto Di Cio, Giuseppe Trunfio (2015) "Kev soj ntsuam kev soj ntsuam ntawm Ammonia Temperature-Programmed Desorption Method rau Kev Tshawb Fawb Cov Khoom Siv Hluav Taws Xob ntawm Heterogeneous Catalyst Surfaces" Applied Catalysis A: Review 503, 227-23
Nkaum analytics. (Lub Ob Hlis 9, 2022). Kev soj ntsuam kev soj ntsuam ntawm cov txheej txheem ntawm kub-programmed desorption ntawm ammonia los kawm cov kua qaub ntawm heterogeneous nto ntawm catalysts. AZ. Tau txais lub Cuaj Hlis 7, 2023 los ntawm https://www.azom.com/article.aspx?ArticleID=14016.
Nkaum analytics. "Kev soj ntsuam ntawm qhov kub thiab txias-Programmed Ammonia Desorption Method for Studying the Acid Properties of Heterogeneous Catalyst Surfaces". AZ. Peb Hlis 7, 2023
Nkaum analytics. "Kev soj ntsuam ntawm qhov kub thiab txias-Programmed Ammonia Desorption Method for Studying the Acid Properties of Heterogeneous Catalyst Surfaces". AZ. https://www.azom.com/article.aspx?ArticleID=14016. (Tau txais: Cuaj hlis 7, 2023).
Nkaum analytics. 2022. Kev soj ntsuam kev soj ntsuam ntawm qhov kub-programmed ammonia desorption txoj kev kawm txog cov kua qaub ntawm cov heterogeneous catalyst nto. AZoM, nkag rau 7 Cuaj hlis 2023, https://www.azom.com/article.aspx?ArticleID=14016.
Post lub sij hawm: Sep-07-2023
