Hollow Mesoporous Metal Organic Framework Single Crystals Enabled by Growth Kinetics Control for Enhanced Photocatalysis

The tailored design of hollow mesoporous metal-organic framework (MOF) single crystals to realize the unimpeded mass transport and long-range carrier migration for advanced photoelectric applications is attractive while being a major challenge. Here, a kinetically mediated micelle assembly strategy is presented to synthesize hollow UiO-66(Ce) single crystals in 1,3,5-trimethylbenzene (TMB)-H2O emulsion system with Pluronic F127/P123 as dual surfactants. This synthesis features the employment of modulator acetic acid, which can coordinate growth kinetics of MOFs, allowing the nucleation of MOF on block polymer micelles and transforming the self-assembly of block polymer/MOF composite monomicelles from water to TMB/H2O emulsion interface and the growth of MOF from aggregation to oriented attachment, and thus ensuring the formation of hollow mesoporous UiO-66(Ce) single crystals. Moreover, a precise control in cavity diameter from approximate to 0 to approximate to 600 nm, mesopore structure from close to radial and dendritic can be achieved by tuning the amount of TMB and the ratio of F127/P123. As a result, the hollow mesoporous UiO-66(Ce) single crystals with large radial mesopores (approximate to 25 nm) and high surface area (approximate to 1061 m2 g) exhibit excellent photocatalytic performance for H-2 generation owing to enhanced permeability and suppressed electron-hole combination.