Ib qho kev sib tw loj tshaj plaws rau kev lag luam ntawm hydrogen roj hlwb yog kev tswj hwm tus nqi. Tam sim no tus nqi ntawm cov roj cell tsheb yog li tsib npaug ntawm cov tsheb zoo tib yam. Nws cov ntsiab lus tseem ceeb yog hu ua proton exchange membrane. Nws tuaj yeem cais cov electrons hauv hydrogen rau hauv cov protons, uas tau pauv los ntawm qhov zoo electrode mus rau qhov tsis zoo electrode thiab hnov mob nrog oxygen los tsim dej thiab cua sov. Raws li txoj cai, cov tub ntxhais ntawm cov proton txauv membrane yog catalyst platinum.
Platinum yog cov hlau muaj txiaj ntsig, uas feem ntau yog platinum, cov khoom siv ntawm kab tshoob nplhaib. Txhawm rau txhawb kev siv lag luam loj, nws yog ib qho tsim nyog yuav tsum txo qis ntawm cov catalyst ntawm ib sab, thiab nrhiav cov khoom siv uas tsis tshua muaj nqi ntawm lwm cov tes.