Tsis muaj kev txhawb nqa thiab txhawb nqa hlau catalysts
Kev faib tawm raws li seb cov khoom siv ntawm cov catalyst tau thauj khoom ntawm kev txhawb nqa lossis tsis:
Tsis muaj kev txhawb nqa hlau catalysts
Nws yog hais txog cov hlau catalysts uas tsis muaj kev txhawb nqa, uas tuaj yeem muab faib ua ob pawg: monometals thiab alloys raws li lawv muaj pes tsawg leeg. Nws feem ntau yog siv rau hauv daim ntawv ntawm pob txha hlau, hlau mesh, hlau hmoov, hlau hais, hlau chips thiab hlau evaporation films. Lub cev pob txha hlau catalyst yog ib qho alloy ntawm catalytically active hlau thiab txhuas los yog silicon, thiab tom qab ntawd yaj cov txhuas los yog silicon nrog sodium hydroxide tov los tsim ib lub pob txha hlau. Qhov feem ntau siv pob txha catalyst hauv kev lag luam yog pob txha npib tsib xee, uas tau tsim los ntawm M. Rainey ntawm Tebchaws Meskas hauv xyoo 1925, yog li nws tseem hu ua Rainey nickel. Matrix nickel catalysts yog siv dav hauv cov tshuaj tiv thaiv hydrogenation. Lwm cov pob txha caj qaum muaj xws li pob txha cobalt, qaum pob txha tooj liab, thiab pob txha hlau. Cov hlau mesh catalysts yog platinum mesh (saib daim duab) thiab platinum-rhodium alloy mesh, uas yog siv rau hauv cov txheej txheem ntawm ammoniation thiab oxidation los tsim nitric acid.
Txhawb nqa hlau catalysts
Lub catalyst yog txhawb los ntawm cov hlau Cheebtsam ntawm kev txhawb nqa los txhim kho cov dispersion thiab thermal stability ntawm cov hlau Cheebtsam, kom cov catalyst muaj ib tug haum pore qauv, zoo thiab mechanical zog. Feem ntau cov kev txhawb nqa hlau catalysts yog npaj los ntawm impregnating hlau ntsev tov ntawm kev txhawb nqa, thiab txo lawv tom qab nag lossis daus hloov dua siab tshiab 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 (saib Catalyst Manufacturing ).
Monometallic thiab polymetallic catalysts
Kev faib tawm raws li cov khoom nquag ntawm cov catalyst yog ib lossis ntau lub ntsiab lus hlau:
Monometallic catalysts
Hais txog lub catalyst nrog tsuas yog ib qho khoom siv hlau. Piv txwv li, nyob rau hauv 1949, platinum hloov kho catalysts, uas yog thawj zaug siv nyob rau hauv kev lag luam, muaj cov active tivthaiv ntawm ib tug hlau platinum txhawb nyob rau hauv η-alumina muaj fluorine los yog chlorine.
Polymetallic catalysts
Cov khoom siv hauv cov catalyst yog tsim los ntawm ob lossis ntau dua hlau. Piv txwv li, bimetallic (multi-) hlau hloov pauv catalysts xws li platinum-rhenium txhawb nqa ntawm chlorine-muaj-alumina. Lawv muaj kev ua tau zoo tshaj plaws ntawm platinum-tsuas yog hloov kho cov catalysts tau hais los saum toj no, uas muaj ntau yam hlau uas tau txais kev txhawb nqa tuaj yeem tsim binary lossis multivariate hlau pawg, uas zoo heev txhim kho cov txiaj ntsig zoo ntawm cov khoom siv. Lub tswv yim ntawm hlau atom pawg tebchaw ua ntej los ntawm complexing catalysts, thiab thaum siv rau cov khoom hlau catalysts, nws tuaj yeem txiav txim siab tias tseem muaj ntau, kaum ob lossis ntau dua hlau atoms pawg ntawm cov hlau. Txij li thaum xyoo 70s, raws li lub tswv yim no, ib qho qauv ntawm qhov chaw nquag ntawm cov hlau atomic pawg tau raug npaj los piav qhia txog cov txheej txheem ntawm qee qhov kev cuam tshuam. Hauv kev txhawb nqa thiab tsis muaj kev txhawb nqa polymetallic catalysts, yog tias ib qho alloy yog tsim los ntawm cov khoom siv hlau, nws yog hu ua alloy catalyst. Binary alloy catalysts tau kawm ntau dua thiab siv, xws li tooj liab-nickel, tooj liab-palladium, palladium-silver, palladium-kub, platinum-kub, platinum-tooj liab, platinum-rhodium, thiab lwm yam. kho qhov muaj pes tsawg leeg ntawm alloy. 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 hloov vim qhov kev nplua nuj ntawm tooj liab nyob rau saum npoo, kom cov dej ua haujlwm ntawm ethane txo qis sai. Alloy catalysts yog siv hauv hydrogenation, dehydrogenation, oxidation, thiab lwm yam.