Synthesis of mesoporous titania thin films (MTTFs) with two different structures as photocatalysts for generating hydrogen from water splitting

We researched the structural effect of titania photocatalysts on the yield of hydrogen gas from water splitting. We synthesized mesoporous titania thin films (MTTFs) with two different structures (that is, pillar structure and tube structure, denoted as P-MTTFs and T-MTTFs, respectively) through an evaporation-induced self-assembling (EISA) process with the presence of a surfactant as a structure-directing agent. The synthesized MTTFs were carefully characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis spectra. After analysis of photocurrent and hydrogen generation, we concluded that with different structures, MTTFs generate photocurrents and hydrogen with different efficiencies. The results indicated that the T-MTTF had a higher net current (i.e., 1.05 E−3 eV) than the P-MTTF (i.e., 1.04 E−3 eV). However, the yield of hydrogen from T-MTTFs (i.e., 17.5 μmol) was lower than that of P-MTTFs (i.e., 37.5 μmol). Tube structure induced a concentration gradient of NaOH, which restrained the generation of oxygen and hydrogen.

► Pillar- and tube-typed mesoporous titania thin films (MTTFs) are successfully synthesized.
► The MTTFs were used, for the first time, for hydrogen generation from water splitting.
► The pillar-typed MTTFs generated more hydrogen than tube-typed MTTFs.
► This is the first fundamental study of the effects of TiO2 nanostructures on the production of hydrogen.
► The pillar-typed MTTFs will be a useful catalyst for photocatalytic applications.