Ultrathin polydopamine coated TiO2 to anchor Pt nanoparticles for enhanced photocatalytic hydrogen evolution

Loading Pt nanoparticles as co-catalyst on inorganic semiconductor is an effective way to surmount the fast recombination of e- /h+ to improve the photocatalytic H2 production. However, the Pt nanoparticles still face serious aggregation and instability on the semiconductor surface. Herein, in order to relieve the above issues, polydopamine (PDA) film with about 2.3 nm was coated on P25 to anchor Pt nanoparticles and the catalysts of P25/PDA-Pt were fabricated. The presence of PDA leads to highly dispersed Pt nanoparticles on the surface of P25/PDA composite and is beneficial for the existence of Pt2+ besides the Pt0. The PDA not only accelerated electron transfer of TiO2 due to its pi conjugated structure but also expanded the light absorption. In addition, the PDA-Pt2+ interactions facilitated the electron transfer from P25/PDA to the co-catalyt of Pt nanoparticles. The P25/PDA-15%-1%Pt(CR) exhibited the optimum hydrogen production rate of 22.1 mmol g- 1 h- 1 being 1.4 times that of P25 loaded with Pt nanoparticles. This study provides novel insights for the development of metal- modified organic/inorganic semiconductors catalyst.