The NiOx films were fabricated using a modified method reported by Sun et al. . A mixture of 2.74 g of NiCl2, 1.5 g of deionized water, 1.5 g of ethanol and 0.5 g of PEG 10,000 was stirred for 24 h. The ratio was selected to obtain a 44 wt% content of NiCl2. The films were deposited onto FTO glasses by dip coating for 10 min with a withdrawal speed of 25 mm s -1 .