Enhanced photocatalytic hydrogen production performance of pillararene-doped mesoporous TiO2 with extended visible-light response

Abstract

Pillararenes are a new type of supramolecular hosts, and they have been widely applied in drug delivery, catalysis, separation process, and sensors. However, they have rarely been used to produce hydrogen. Here, we report that pillararenes were used as functional molecules to explore photocatalysts and efficiently promoted hydrogen production from water. The most common and easily synthesized p-dimethoxy pillar[5]arene (PI-OMe) was employed to form an organic-inorganic hybrid material with titanium dioxide (TiO2), denoted as PI-OMe-TiO2, using a convenient sol-gel method. When the material was loaded with Pt nanoparticles, the resulting Pt/PI-OMe-TiO2 had a good activity and stability in catalyzing water splitting to produce hydrogen under visible light. The optimized catalyst Pt/PI-OMe-TiO2(5.2 wt%) had a photocatalytic hydrogen production rate of 1736 µmol g−1 h−1 under visible light (λ > 420 nm) irradiation. The catalyst with a Pt loading of 0.5 wt% and a PI-OMe content of 5.2 wt% also showed good long-term durability after 10 cycles of 50 h testing. The total amount of hydrogen produced was 65.01 mmol/g, and the corresponding turnover number (TON) value was 2084. Our findings suggest that pillararene derivatives are promising functional molecules to make efficient and stable hybrid photocatalysts with TiO2 and open a new door to hydrogen production using visible light.