Hydrogen isotope enrichment through liquid-phase catalytic exchange (LPCE) technology is achieved in a hydrophobic reaction environment to avoid liquid water poisoning, but the usage of hydrophobic support severely inhibits the internal diffusion of water molecules to decrease the catalytic efficiency. Herein, we encapsulate platinum active sites into a metal organic framework (Pt@NH2-UiO-66) as the efficient catalyst for LPCE via introducing hydrophilic amino groups. Experiments and density functional theory simulation reveal amino groups in the channel as the adsorption site of water molecules accelerates the internal diffusion and slows down the accumulation on the platinum sites. Meanwhile, the amino groups interact with the Pt site bridge electron transfer from active sites to support the host, thus decreasing the catalytic reaction and generated water desorption barrier. Due to these positive roles, the turnover frequency of Pt@NH2-UiO-66 reaches 2272 h-1 in a microchannel reactor. This work provides a novel design strategy of catalysts in LPCE.
Keywords: LPCE; adsorption site; amino group; electron transfer; encapsulated catalyst.