Facile synthesis of Ni-doped WO3 nanoplate arrays for effective photoelectrochemical water splitting

• Published in: Journal of solid state electrochemistry 2017-11, Vol.21 (11), p.3355-3364
• Main Authors: Xiao, Yong-Hao, Xu, Cheng-Qun, Zhang, Wei-De
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Electrochemistry; Energy measurement; Energy Storage; Monoclinic lattice; Original Paper; Physical Chemistry; Tungsten oxides; Water splitting
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-017-3680-6

A two-step hydrothermal process for preparing Ni-doped WO 3 nanoplate arrays (NPAs) is developed, and the obtained samples were used as a photoanode to produce a highly active and stable electrocatalyst for photoelectrochemical (PEC) water splitting under visible light. The NPAs are formed as a single-phase solid solution with high purity. X-ray photoelectron spectroscopy measurement verifies the binding energy of W element is negatively shifted due to the substitution of W 6+ by Ni 2+ in the monoclinic lattice and thereby the formation of Ni-O-W bonds. Notably, the two-step 3 at% Ni-doped WO 3 NPAs exhibits the highest PEC performance, compared with pure and one-step Ni-doped WO 3 NPAs. At 1.0 V (vs Ag/AgCl), the current density of two-step 3 at% Ni-doped WO 3 is 0.80 mA/cm 2 , which is about 1.74- and 2.35-fold of that of WO 3 (0.46 mA/cm 2 ) and one-step 3 at% Ni-doped WO 3 (0.34 mA/cm 2 ), respectively. The PEC performance of WO 3 NPAs can be modified by Ni doping in a two-step hydrothermal process; both the changes of band gap and electrochemically active surface area (ECSA) are playing important roles on improving the activity of the WO 3 NPAs photoanode.