Photoelectrochemical and photocatalytic water splitting to generate hydrogen are regarded as potential methods to obtain hydrogen. In the semiconductor photocatalytic dispersion, noble metallic Pt is usually used as a co-catalyst to catalyze those reactions. However, Pt can also act as an active center for H₂ and O₂ recombination back reaction, which results in the very low photocatalytic efficiency for H₂ generation. Here we reported that the recombination rate nearly linearly increased with the increase of Pt loading amount in the low Pt loading region, while decreased in high Pt loading region. Very trace amount of fluorine ion can remarkably inhibit hydrogen and oxygen recombination. Detail study indicated that this inhibition was achieved via the occupation of hydrogen and oxygen adsorption and activation sites by fluorine ion over Pt due to the strong tendency of adsorption of fluorine ion on Pt. By taking advantage of this inhibition role of fluorine ions, the Pt/TiO₂ activity for water splitting is remarkable enhanced up to 2.3 times. Isotope experiments with D₂O and H₂¹⁸O confirmed hydrogen and oxygen were both from water. Our results clearly indicated that the excellent photocatalytic performance for water splitting over fluorine doped on TiO₂ might be related to the role of fluorine inhibition on H₂ and O₂ recombination back reaction, which would shine light to the new photocatalyst preparation for water splitting.

光电化学和光催化水分解产生氢被认为是获得氢的潜在方法。在半导体光催化分散体中，通常将贵金属Pt用作助催化剂以催化那些反应。然而，Pt还可作为H ₂和O ₂重组反反应的活性中心，这导致H _2的光催化效率非常低。一代。在这里，我们报道了重组率随着低Pt负载区域中Pt负载量的增加而线性增加，而在高Pt负载区域中降低。极微量的氟离子可以显着抑制氢和氧的重组。详细研究表明，这种抑制作用是由于氟离子在Pt上有很强的吸附趋势，因此氟离子在Pt上占据了氢和氧的吸附和活化位点。通过利用氟离子的这种抑制作用，Pt / TiO ₂的水分解活性显着提高到2.3倍。D ₂ O和H ₂ ^18的同位素实验O确认氢和氧均来自水。我们的结果清楚地表明，掺杂TiO _2的氟对水分解的优异光催化性能可能与氟抑制对H ₂和O _2的重组逆反应的作用有关，这将为新型的水分解光催化剂制备提供光亮。