Effect of noble metals loaded TiO₂ on the selectivity of photocatalytic CO₂ reduction

The TiO₂ photocatalyst loaded with 1% Pt, Pd, Au, Ag have been prepared by photo deposition method. The catalysts are characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis spectrometer. The electro-catalytic performance for hydrogen production and photo electrochemical performance are investigated by using linear sweep voltammetry method and continuous transient current-time response method. The performance of photocatalytic CO₂ reduction on TiO₂ loaded with different noble metals are discussed. The results show that loading noble metal on TiO₂ can significantly accelerate the separation of photo production electron and hole and reduce the recombination rate. Furthermore, the sequence of cocatalysts selective reduction for CO₂ is Ag>Au>Pd>Pt. A negative correlation between the selectivity of CO₂ hydrogenation and hydrogen production has been discovered. The cocatalyst which has advantage to hydrogen evolution process goes against the selectivity of CO₂ hydrogenation.