Photocatalytic hydrogen production using copper-based nanoparticles and TiO2

Abstract

Photocatalytic hydrogen production is sustainable and clean hydrogen production method. Using semi-conductor nanoparticles (NPs), hydrogen can be obtained from water and sun light both of which are sustainable. However, the photocatalytic hydrogen production has limitation for practical application so far. It is because of the limitation of capacity, high cost and low reactivity. In this study, novel approaches for fabrication of cheap and mass-producible photocatalysts were suggested. At first, cheap and efficient photocatalysts were fabricated by simply mixing TiO2 NPs and CuO NPs. The two NPs combined with each other to form TiO2/CuO mixture in an aqueous solution due to the opposite surface charge. The TiO2/CuO mixture exhibited photocatalytic hydrogen production rate of up to 8.23 mmol h-1 g-1 under Xe lamp irradiation when the weight ratio of P25 to CuO was optimized to 10. Although the conduc-tion band edge position of CuO NPs is more positive than normal hydrogen electrode, the TiO2/CuO mixture exhibited good photocatalytic hydrogen production performance because of the inter-particle charge transfer between the two NPs. The detailed mechanism of the photocatalytic hydrogen production is discussed. This mixing method does not require a complicated chemical process and allows mass production of the photocatalysts. Additionally, thermal deposition of electron acceptors on TiO2 using bottom heating was carried out. I demonstrated that bottom heating of the methanol aqueous solution containing TiO2 and H2PtCl6 precursor can fabricate Pt deposited TiO2. The heating process replaced UV illumination of photo deposition which is the most widely used noble metal acceptor deposition method. UV illumination has limitation on capacity due to the small beam diameter of light source. The thermal deposition method has potential application for mass-production for practical use. Fabrication method of visible light responsive Cu/TiO2 by illuminating UV light on the mi...