A Ni(OH)2-modified Ti-doped α-Fe2O3 photoanode for improved photoelectrochemical oxidation of urea: the role of Ni(OH)2 as a cocatalystElectronic supplementary information (ESI) available: Photoelectrochemical impedance spectra (PEIS) of all samples recorded at an applied potential of 1.0 VRHE to explore the resistance of hole transfer at the semiconductor/liquid interface are shown in Fig. S1. Charge densities accumulated at the surface of the photoanode at different applied potentials of Ti-Fe

• Main Authors: Xu, Dandan, Fu, Zewen, Wang, Dejun, Lin, Yanhong, Sun, Yanjun, Meng, Dedong, feng Xie, Teng
• Format: Article
• Language: English
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c5cp03310a

For semiconductor-based PEC systems, loading an appropriate cocatalyst on a semiconductor (such as a solar-active material) can significantly improve the PEC activity due to the suppression of photogenerated charge recombination. But there is little direct information about the role of a cocatalyst in the spatial separation of photogenerated charge carriers. In our work, a combination of surface photovoltage spectroscopy (SPS), transient photovoltage (TPV) technique, photoelectrochemical impedance spectroscopy (PEIS) and transient photocurrent measurements was used to study the real role of Ni(OH) 2 as a cocatalyst for the enhanced PEC performance of Ni(OH) 2 -modified Ti-doped α-Fe 2 O 3 . It was found that Ni(OH) 2 as a hole storage layer enhances the separation of photogenerated charge carriers and increases the lifetime of holes, which contributed to the enhanced photocurrent. In addition, Ni(OH) 2 is a good cocatalyst for urea oxidation which suppresses the over-potential, resulting in a negative shift of the onset potential. Ni(OH) 2 , as a hole storage layer, enhances the separation of photogenerated charge carriers, which contributes to enhanced photocurrent.