Qhov Tseem Ceeb Qhov txawv - Homogeneous vs Heterogeneous Catalyst
Catalysts muaj ntau hom, tab sis lawv tuaj yeem raug faib ua ob pawg ua homogeneous catalysts thiab heterogeneous catalysts. Qhov sib txawv tseem ceeb ntawm homogeneous thiab heterogeneous catalysts yog tias homogeneous catalysts yeej ib txwm pom nyob rau hauv cov kua theem whereas heterogeneous catalysts muaj nyob rau hauv tag nrho peb theem ntawm teeb meem: khoom theem, kua theem, thiab roj theem.
Catalysts yog cov khoom sib xyaw uas siv los ua kom tau txais txiaj ntsig siab tshaj plaws hauv cov xwm txheej me. Qhov no txhais tau hais tias, cov catalysts tuaj yeem ua rau cov txiaj ntsig ntawm cov tshuaj tiv thaiv tshwj xeeb thiab ua kom cov tshuaj tiv thaiv sai.
Homogeneous Catalyst yog dab tsi?
Homogeneous catalysts yog cov catalytic compounds uas nyob rau hauv tib theem li cov tshuaj uas yuav mus rau hauv cov tshuaj tiv thaiv theem. Cov homogeneous catalysts no feem ntau nyob rau hauv cov kua theem. Kev rov qab los ntawm homogeneous catalysts yog qhov nyuaj thiab kim vim tias cov catalyst nyob rau tib theem raws li cov tshuaj tiv thaiv sib tov. Qhov no txhais tau tias cov catalyst sib cais yog qhov nyuaj. Lub thermal stability ntawm homogeneous catalysts kuj tsis zoo. Cov piv txwv feem ntau rau homogeneous catalysts yog meta complexes.
Daim duab 01: Kev Ua Haujlwm ntawm Catalysts
Homogeneous catalysts ua haujlwm tau zoo nyob rau hauv qhov kub thiab txias (tsawg dua 250◦C). Kev ua haujlwm catalytic ntawm cov catalysts yog nruab nrab thaum piv rau heterogeneous catalysts. Txawm li cas los xij, qhov kev xaiv yog siab heev. Kev rov ua dua ntawm homogeneous catalyst yog kim vim tias qhov kev rov ua kom rov qab tau yooj yim. Tab sis kev hloov kho ntawm cov catalyst yog ib qho yooj yim vim nws nyob rau hauv cov kua theem.
Qhov diffusivity ntawm homogeneous catalysts siab. Qhov no vim hais tias tag nrho cov reactants thiab cov catalyst nyob rau tib lub sij hawm ua kua thiab kom zoo stirring ua rau kom zoo diffusion ntawm catalyst thoob plaws hauv cov tshuaj tiv thaiv sib tov. Homogeneous catalysts feem ntau muaj cov chaw ua haujlwm zoo. Qhov no txhais tau hais tias muaj ntau qhov chaw ua haujlwm zoo nyob rau saum npoo ntawm catalyst compound mus rau cov reactants tau khi, thiab cov tshuaj tiv thaiv tau nce mus rau cov chaw nquag.
Dab tsi yog Heterogeneous Catalyst?
Heterogeneous catalysts yog cov catalytic compounds uas nyob rau theem sib txawv ntawm theem ntawm cov tshuaj tiv thaiv sib xyaw. Cov catalysts tuaj yeem pom nyob rau hauv tag nrho peb theem ntawm cov teeb meem: theem khoom, theem ua kua lossis roj theem. Lub catalytic rov qab yog yooj yim thiab pheej yig nyob rau hauv heterogeneous catalysts txij li thaum lub catalyst nyob rau hauv ib tug txawv theem ntawm cov theem ntawm cov tshuaj tiv thaiv sib tov. Feem ntau piv txwv rau heterogeneous catalysts yog hlau, hlau oxides, thiab lwm yam.
Daim duab 2: Cov tshuaj tiv thaiv sib xyaw yog nyob rau theem ua kua thaum Catalyst yog hlau nyob rau theem khoom
Lub thermal stability ntawm heterogeneous catalysts zoo heev piv rau homogeneous catalysts. Cov catalysts ua tau zoo nyob rau hauv qhov kub thiab txias, nyob ib ncig ntawm 250-500◦C. Cov kev ua catalytic kuj siab thaum piv rau homogeneous catalysts. Txawm li cas los xij, kev xaiv ntawm cov tshuaj reactants tsis zoo dua li cov homogeneous catalysts. Cov chaw nquag ntawm heterogeneous catalysts tsis zoo-txhais tau. Qhov no txo qis kev xaiv.
Qhov diffusivity ntawm heterogeneous catalyst yog qhov tsis zoo yog tias thaj tsam ntawm cov catalyst tsawg vim tias cov catalyst thiab cov tshuaj tiv thaiv sib xyaw yog nyob rau hauv ob theem. Tab sis kev sib cais ntawm cov catalyst feem ntau yog ncaj nraim. Tom qab ntawd kev rov ua dua ntawm cov catalyst kuj yooj yim.
Qhov txawv ntawm Homogeneous thiab Heterogeneous Catalyst yog dab tsi?
Homogeneous vs Heterogeneous Catalyst |
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| Homogeneous catalysts yog cov tshuaj catalytic uas nyob rau theem tib yam li cov tshuaj uas nkag mus rau theem tshuaj tiv thaiv. | Heterogeneous catalysts yog cov catalytic compounds uas nyob rau theem sib txawv ntawm cov theem ntawm cov tshuaj tiv thaiv sib tov. |
| Phase | |
| Homogeneous catalysts tuaj yeem pom feem ntau hauv cov kua theem. | Heterogeneous catalysts tuaj yeem pom nyob rau hauv tag nrho peb theem; theem khoom, theem ua kua lossis roj theem. |
| Thermal Stability | |
| Qhov thermal stability ntawm homogeneous catalysts tsis zoo. | Lub thermal stability ntawm heterogeneous catalysts yog qhov zoo. |
| Catalyst Recovery | |
| Kev rov qab los ntawm homogeneous catalysts nyuaj thiab kim. | Kev rov qab los ntawm cov catalysts heterogeneous yog ib qho yooj yim thiab pheej yig. |
| Active Site | |
| Qhov chaw nquag ntawm homogeneous catalysts tau txhais tau zoo thiab muaj kev xaiv zoo. | Qhov chaw nquag ntawm cov catalysts tsis zoo txhais tau zoo thiab muaj kev xaiv tsis zoo. |
| Catalyst Recycling | |
| Kev rov ua dua ntawm homogeneous catalysts nyuaj. | Kev rov ua dua ntawm heterogeneous catalysts yog ib qho yooj yim. |
| Catalyst Separation | |
| Kev sib cais ntawm homogeneous catalyst los ntawm cov tshuaj tiv thaiv sib tov yog qhov nyuaj. | Kev sib cais ntawm heterogeneous catalyst los ntawm cov tshuaj tiv thaiv sib tov yog ib qho yooj yim. |
| Kev Tiv Thaiv Kub | |
| Homogeneous catalysts ua haujlwm zoo dua hauv qhov kub thiab txias (tsawg dua 250◦C). | Heterogeneous catalysts ua haujlwm zoo dua hauv qhov kub thiab txias (kwv yees li 250 txog 500◦C). |
| Catalyst Hloov kho | |
| Kev hloov pauv ntawm homogeneous catalysts yog ib qho yooj yim. | Kev hloov pauv ntawm cov catalysts heterogeneous yog qhov nyuaj. |
Summary – Homogeneous vs Heterogeneous Catalyst
Catalysts yog cov tebchaw uas tuaj yeem nce cov tshuaj tiv thaiv ntawm cov tshuaj tiv thaiv tshwj xeeb kom muab cov txiaj ntsig zoo hauv lub sijhawm luv luv. Muaj ob hom catalysts hu ua homogeneous catalysts thiab heterogeneous catalysts. Qhov sib txawv tseem ceeb ntawm homogeneous thiab heterogeneous catalysts yog tias homogeneous catalysts yeej ib txwm pom nyob rau hauv cov kua theem whereas heterogeneous catalysts muaj nyob rau hauv tag nrho peb theem ntawm teeb meem; theem khoom, theem ua kua, thiab roj theem.
