Chemically anchored platinum atoms greatly enhance the efficiency of TiO2 in photocatalytic hydrogen production
Scientists from the RCPTM photoelectrochemistry group, led by Professor Patrick Schmuki, have developed new technology enabling individual platinum atoms to be anchored to the TiO2 surface. Titanium dioxide is one of the most studied photocatalysts, which is used as a photoanode in the process of producing hydrogen through direct solar water splitting. Platinum represents the most commonly used co-catalyst contributing to increasing the efficiency of converting solar energy into hydrogen. Primarily, platinum is used in the form of nanoparticles of different sizes and shapes. Recent rapid development in synthesis and properties of catalysts at the level of individual atoms (the so-called single atom catalysis) has inspired scientists to develop a unique technology based on partial reduction of TiO2 in the hydrogen atmosphere under the simultaneous formation of Ti3+ and surface defects. These defects act as chemical traps to anchor individual platinum atoms after simple impregnation with Pt4+ solution. The method allows elegant control of surface defect density and the rates of TiO2 layer coverage by individual platinum atoms. Such bound atoms increase the photocatalytic efficiency of titanium dioxide up to 150-fold, compared to the commonly used systems in which platinum nanoparticles are applied to the surface of TiO2. The work, published in the journal Advanced Materials, follows RCPTM’s systematic research into metal oxides for photocatalytic applications including direct solar water splitting (Kment S. et al. Chem. Soc. Rev. 46, 3716–3769, 2017; Spanu D. et al. ACS Catal. 8, 5298–5305, 2018; Naldoni A. et al. ACS Catal. 9, 345–364, 2019) and into using metals at the level of individual atoms in organic catalysis, electrocatalysis and photocatalysis (Bakandritsos A. et al. Adv. Mater. 31, 1900323, 2019; Gawande M. B. et al. ACS Catal. 10, 2231–2259, 2020).
Hejazi S., Mohajernia S., Osuagwu B., Zoppellaro G., Andryskova P., Tomanec O., Kment S., Zbořil R., Schmuki P.: On the Controlled Loading of Single Platinum Atoms as a Co‐Catalyst on TiO2 Anatase for Optimized Photocatalytic H2 Generation, Advanced Materials, 32 (16), 1908505, 2020.