Improved H2 yields over Cu-Ni-TiO2 under solar light irradiation: Behaviour of alloy nano particles on photocatalytic H2O splitting

Cu-Ni-TiO2 showed a distinct surface plasmon resonance (SPR) due to a synergetic interaction between Ni and Cu resulted in a suitable electron-hole separation consequently the charge carriers were easily transferred to TiO2 surface. The Cu-Ni bimetallic alloy particles with the localized SPR demonstrated the ability to absorb the wide range of wavelength (400-800 nm) in the visible light. The SPR band red-shifted from UV window to near-infrared and covered the entire UV-visible light region stemmed to avail full advantage of sunlight in the photocatalytic H2O splitting. The bimetallic 2Cu-5Ni/TiO2 catalyst showed visible light H2O splitting under solar light with a H2 yield ca. 0.20 mmol g-1 h-1 in the absence of a sacrificial agent and ∼ 35.4 mmol g−1 h−1, while H2O + CH3OH mixture was used. The SPR behaviour of Cu-Ni alloy particles was explained by H2-TPR, N2O titration, XRD, TEM, UV-DRS, XPS, PL and Raman spectroscopy.