Graphene and MOFs co-modified composites for high adsorption capacity and photocatalytic performance to remove pollutant under both UV- and visible-light irradiation

Various metal organic frameworks (MOFs) including ZIF-8, Uio-66 and Cu-BTC are prepared and adopted with reduced graphene oxide (RGO) to co-modify TiO2. The resulting composite photocatalysts display high photocatalytic performances under both UV- and visible-light irradiation, and the corresponding photocatalytic mechanisms are revealed by considering the electronic structures and morphologies of these ingredients, which are proven by IR curves, STM patterns, lifetime of photoinduced electrons. The influences of BET areas and pore diameters of the adopted MOFs on the resulting photocatalytic properties are studied, and the specific influence of interaction between TiO2 and RGO on the observed photocatalytic activities are also discussed. The large BET areas of the MOFs endow high adsorption capacities to the resulting photocatalysts, while the closely chemical contact between TiO2 and RGO achieves the visible-light activity. After optimization, the degradation rate constants of rhodamine-B reach 1.65 ​× ​10-1 min-1 and 1.12 ​× ​10-1 min-1 under UV- and visible-light irradiation, respectively.