Paired PTA-Pt photocatalysis in ordered nanoconfined channels for water slitting - hydrogen and oxygen production

Je-Wei Chang^1*, Jin-Jia Tsai², Yu-Cheng Hsu², Ying-Huang Lai², U-Ser Jeng^1,3

¹Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan
²Department of Chemistry, Tunghai University, Taichung, Taiwan
³National Synchrotron Radiation Research Center, Hsinchu, Taiwan

* Presenter:Je-Wei Chang, email:weinanochang@gmail.com

Optimizing the use of platinum nanoparticles (Pt-NPs) in hydrogen production is of sustained interest. Other than the size and shape effects, the hydrogen catalytic efficiency can be further enhanced with closely packed Pt-NPs with catalysts for complementary or synergistic effects. Here, we present an air-liquid-interface directed synthesis for a silicatropic template, with polyoxotungstate (H₃PW₁₂O₄₀; PTA) embedded on the silica channel walls and arrayed Pt-NPs inside the silica channels. With in situ grazing incidence small-angle X-ray scattering (GISAXS) on the air-liquid interface formations of highly ordered and uniaxially oriented silicatropic template and the subsequent Pt-NP arrays in the template are traced. The structural evolution of the channel-channel spacing reveals the precursor adsorption and anion-exchange effect for Pt-NP formation. The hence formed composite with the efficient catalytic pairs of Pt-NP and PTA demonstrates efficient transport of photo-electrons for hydrogen production and migrate of photo-holds for oxygen production, upon light illumination. With the nanochannel confinement, aggregation of the bare-surface Pt-NP of ca. 2 nm is greatly suppressed. Consequently, the Pt-NPs-PTA@silica composite with the catalytic pair of Pt-NP and PTA exhibits double-function material for produce hydrogen and oxygen by photocatalytic water splitting.

Keywords: Photocatalytic water splitting, Platinum-Nanoparticles, Mesostructured Silica, Grazing-Incidence Small-Angle X-Ray Scattering