Positive Ni(HCO3)2 as a Novel Cocatalyst for Boosting the Photocatalytic Hydrogen Evolution Capability of Mesoporous TiO2 Nanocrystals

A highly efficient hybrid photocatalytic system consisting of Ni(HCO 3 ) 2 and mesoporous TiO 2 microrods was successfully fabricated by a hydrothermal approach. The involvement of Ni(HCO 3 ) 2 cocatalyst resulted in significant improvement of the hydrogen evolution on the host TiO 2 photocatalyst under artificial sunlight irradiation. The optimized hybrid photocatalysis system with 2.5% (mole ratio) Ni(HCO 3 ) 2 loading displayed the highest hydrogen evolution rate of 1798.0 μmol g –1 h –1, which was more than 18 times higher than that of pure mesoporous TiO 2 . On the basis of the photoluminescence spectroscopy and photoelectrochemical measurement results, it is proposed that the enhancement of photocatalytic hydrogen evolution capability on the TiO 2 –Ni(HCO 3 ) 2 host photocatalyst–cocatalyst is not only attributed to the efficient separation of photoinduced electron–hole pairs, but also derived from the Ni(HCO 3 ) 2 cocatalyst acting as active reaction sites toward hydrogen production.