Efficient and Long-term Photoelectrochemical Hydrogen Liberation from Hydrazine Hydrate on CdS Nanorod Arrays

Abstract Efficient and long-term photoelectrochemical (PEC) hydrogen liberation from hydrazine hydrate was achieved using CdS nanorod arrays (CdS NRs) as the photoelectrode. Under light irradiation, the CdS photoelectrode exhibited high efficiency and stability for the anodic oxidation of N 2 H 4 ·H 2 O with high selectivity for hydrogen production at the counter cathode. The yield and Faradic efficiencies (FE) of hydrogen from N 2 H 4 ·H 2 O solution under mild conditions were determined to be 658 μmol/cm 2 and 90%, respectively, after 5 h of operation. The photocurrent density of the CdS electrode in electrolyte with N 2 H 4 ·H 2 O reached 7.6 mA/cm 2 at 1.23 V versus RHE, five times higher than that in N 2 H 4 ·H 2 O free electrolyte. And the persistence of CdS electrodes in electrolytes with N 2 H 4 ·H 2 O was more than 100 h, while in N 2 H 4 ·H 2 O free electrolytes, it was less than 100 s. An obvious cathodic shift of the photocurrent onset potential of about 300 mV was also observed. Furthermore, the kinetics of PEC oxidation of N 2 H 4 ·H 2 O were further tested. In addition, it is expected that this work may provide a strategy to stabilize other unstable photoelectrodes for a wide range of applications and supply a way to produce hydrogen by photoelectrochemical decomposition of N 2 H 4 ·H 2 O. Graphical Abstract