P-type β-Ni(OH)2 nanoparticles sensitize CdS nanorod array photoanode to prolong charge carrier lifetime and highly improve bias-free visible-light-driven H2 evaluation

Abstract

Here, we report a novel β-Ni(OH)2@CdS shell-core nanorod array (NRA) photoanode with prolonged lifetime for highly efficient H2 generation. The fabricated photoanode shows drastically enhanced ability to generate H2 from water splitting under bias-free visible light irradiation. The H2 production rate of β-Ni(OH)2@CdS NRA photoelectrode reaches 762.5 μmol h-1, 8 times as high as that of pure CdS NRA photoelectrode. In addition, the constructed β-Ni(OH)2@CdS shell-core NRA photoanode exhibits an outstanding stability. Mott-Schottky measurements clearly demonstrate that both p-n junction and type-II band alignment are established at β-Ni(OH)2 and CdS interface. This unique band structure is highly favorable for the transfer and separation of charge carriers, significantly suppressing charge recombination, as confirmed by photoluminescence emission study. Moreover, the measurements of electrochemical spectroscopy undoubtedly confirm that the lifetime of charge carriers within this unique band structure is significantly prolonged, leading to drastically enhanced photoelectrochemical water splitting for H2 generation.