Kev faib tawm ntawm cov hlau catalysts

Tsis txhawb thiab txhawb nqa hlau catalysts

Raws li seb lub active Cheebtsam ntawm lub catalyst tau txais kev txhawb nqa ntawm cov cab kuj los yog tsis:

Tsis muaj kev txhawb nqa hlau catalyst

Hais txog hlau catalysts tsis muaj tus cab kuj, uas yuav muab faib ua ob hom: ib leeg hlau thiab alloy raws li lawv muaj pes tsawg leeg. Feem ntau siv nyob rau hauv daim ntawv ntawm lub moj khaum hlau, hlau hlau mesh, hlau hmoov, hlau hais, hlau chips thiab hlau evaporation zaj duab xis. Lub moj khaum hlau catalyst yog ua ib qho alloy nrog catalytically active hlau thiab txhuas los yog silicon, thiab tom qab ntawd siv sodium hydroxide tov kom yaj cov txhuas los yog silicon los tsim ib lub moj khaum hlau. Qhov feem ntau siv pob txha catalyst hauv kev lag luam yog pob txha pob txha nickel, uas tau tsim los ntawm M. Raney ntawm Tebchaws Meskas hauv xyoo 1925, yog li nws tseem hu ua Raney npib tsib xee. Skeletal nickel catalysts yog siv dav hauv cov tshuaj tiv thaiv hydrogenation. Lwm lub moj khaum catalysts muaj xws li lub moj khaum cobalt, ncej tooj liab thiab lub moj khaum hlau. Hom hlau hlau mesh catalysts yog platinum mesh (saib daim duab) thiab platinum-rhodium alloy mesh, uas yog siv rau hauv cov txheej txheem ntawm ammoxidation los tsim nitric acid.

Txhawb nqa hlau catalyst

Lub catalyst nyob rau hauv uas cov hlau tivthaiv tau txais kev txhawb nqa ntawm cov cab kuj yog siv los txhim kho cov dispersion thiab thermal stability ntawm cov hlau tivthaiv, thiaj li hais tias cov catalyst muaj ib tug haum pore qauv, zoo thiab txhua yam muaj zog. Feem ntau cov kev txhawb nqa hlau catalysts yog npaj los ntawm impregnating cov hlau ntsev tov ntawm cov cab kuj, thiab txo nws tom qab nag lossis daus transformation los yog thermal decomposition. Ib qho ntawm cov yuam sij rau kev npaj cov kev txhawb nqa hlau catalysts yog tswj kev kho cua sov thiab txo cov xwm txheej.

Tib hlau thiab multi-metal catalysts

Raws li cov catalyst active tivthaiv yog ib los yog ntau tshaj hlau ntsiab faib:

Ib leeg hlau catalyst

Hais txog lub catalyst nrog tsuas yog ib qho khoom siv hlau. Piv txwv li, nyob rau hauv lub platinum hloov kho catalyst thawj zaug siv nyob rau hauv kev lag luam nyob rau hauv 1949, lub active tivthaiv yog ib tug tib hlau platinum txhawb nyob rau hauv η-alumina muaj fluorine los yog chlorine.

Multimetallic catalyst

Cov khoom siv hauv cov catalyst yog tsim los ntawm ob lossis ntau dua hlau. Piv txwv li, platinum-rhenium thiab lwm yam ob (ntau) hlau hloov kho catalysts txhawb ntawm chlorine-muaj γ-alumina. Lawv muaj kev ua tau zoo dua li qhov tau hais los saum toj no hloov kho cov catalysts uas muaj platinum nkaus xwb. Nyob rau hauv hom catalyst no, ntau yam hlau txhawb nqa ntawm cov cab kuj tuaj yeem tsim binary lossis ntau cov ntsiab lus hlau pawg, kom cov txiaj ntsig zoo ntawm cov khoom siv tau zoo tuaj. txhim kho. Lub tswvyim ntawm hlau pawg tebchaw yog thawj zaug los ntawm complex catalysts. Thaum siv rau cov khoom siv hlau hlau, nws tuaj yeem txiav txim siab tias muaj ob peb, kaum ob lossis ntau dua hlau atoms pawg ntawm cov hlau. Txij li thaum xyoo 1970, raws li lub tswv yim no, ib qho qauv ntawm qhov chaw nquag ntawm cov hlau pawg tau raug npaj los piav qhia txog cov txheej txheem ntawm qee qhov kev cuam tshuam. Hauv kev txhawb nqa thiab tsis txhawb nqa multimetal catalysts, yog tias ib qho alloy yog tsim los ntawm cov khoom siv hlau, nws yog hu ua alloy catalyst. Cov kev tshawb fawb thiab siv ntau tshaj yog binary alloy catalysts, xws li tooj liab-nickel, tooj liab-palladium, palladium-silver, palladium-kub, platinum-kub, platinum-tooj ​​liab, platinum-rhodium, thiab lwm yam. los ntawm kev kho qhov muaj pes tsawg leeg ntawm cov alloy. Qee cov hlau catalysts muaj qhov sib txawv ntawm qhov sib txawv ntawm qhov chaw thiab cov theem ntau. Piv txwv li, tom qab ntxiv ib qho me me ntawm tooj liab rau cov nickel catalyst, tus qauv saum npoo ntawm cov nickel catalyst tau hloov vim qhov kev nplua nuj ntawm tooj liab nyob rau saum npoo, yog li hydrogenating ethane. Cov kev ua lysis txo qis sai. Alloy catalysts muaj kev siv hauv hydrogenation, dehydrogenation, oxidation, thiab lwm yam.