Composite of titanium dioxide and hydrogen-bonded organic framework − A dye-sensitized photocatalyst

Abstract

To improve the utilization of TiO2 with low visible light absorption behavior, a 2D hydrogen-bonded organic framework (HOF), HOF-TCPB-373, was employed and integrated with TiO2 to create a composite catalyst (TiO2@HOF). 40 %TiO2@HOF exhibits a larger BET specific surface area (26.68 m2/g) and a more negative Zeta potential (–23.78 mV) compared to HOF-TCPB-373. Compared to TiO2, 40 %TiO2@HOF is more hydrophilic with the water contact angles of 51°. A dye-sensitized catalytic system based on 40 %TiO2@HOF was established. 40 %TiO2@HOF exhibits the highest RhB removal efficiency reaching 99 %, combining photodegradation (69 %) and adsorption (30 %). The 40 %TiO2@HOF composite shows both superior adsorption and photodegradation capacities for RhB compared to pristine TiO2 and HOF-TCPB-373, attributing to the synergistic effect and heterojunction structure formed between the two components. The mechanism of dye sensitization and photocatalytic degradation was explained by energy band analysis and active species capture experiments. The degradation was driven by RhB-excited and charge transfer on 40 %TiO2@HOF.