Photoelectrochemical water splitting represents a promising route for converting solar energy into hydrogen, but sluggish reaction kinetics associated with inefficient charge separation and migration, and poor stability limit solar-to-hydrogen conversion. In this work, we develop a N-doped-CdS/TiO 2 -nanorods heterojunction photoanode for photoelectrochemical water splitting by anchoring CdS on TiO 2 nanorods followed by nitrogen doping. The light harvesting is significantly enhanced and the charge separation and migration are promoted due to the formed heterojunction and nitrogen doping, which greatly enhances the water oxidation reaction. As a result, the photoelectrochemical cell with the optimized N-doped-CdS/TiO 2 -nanorods heterojunction photoanode yields a hydrogen production rate of 42.6 μmol cm −2 h −1 , which is 2.51 times higher than that of the TiO 2 -nanorods photoanode. In particular, doping nitrogen atoms into CdS greatly alleviates the photocorrosion problem. Therefore, the newly-developed photoanode exhibits excellent stability under a continuous 10-h running.
Jie Wei,Aori Qileng,Yun Yan,Hongtao Lei,Shengsen Zhang,Weipeng Liu,Yingju Liu
An ultrasensitive photoelectrochemical (PEC) immunoassay based on multiple signal amplification strategy was fabricated for the detection of microcystin-LR (MC-LR). The CdS/TiO 2 nanorod arrays (CdS/TiO 2 NRAs) modified FTO electrode, which can weaken the self-oxidation by photogenerated holes of CdS nanoparticles , and limit the recombination of electron-hole pairs and broaden optical absorption of TiO 2 NRAs, was used as a visible-light driven material to immobilize antigens. Then, Fe 3 O 4 nanoparticles/polydopamine (Fe 3 O 4 @PDA) was used as the carrier to load secondary antibody (Ab 2 ) and horseradish peroxidase (HRP), where Fe 3 O 4 nanoparticles and HRP can synergistically accelerate the oxidation of 4-chloro-1-naphthol (4-CN) by H 2 O 2 to produce biocatalytic precipitation (BCP) on the surface of modified electrode . Due to the catalytic activity of Fe 3 O 4 nanoparticles and HRP, the nonproductive absorption of HRP and the steric hindrance by BCP, the photocurrent change was amplified. The proposed PEC immunosensor can detect MC-LR in a range of 0.005–500 μg/L with a detection limit of 0.001 μg/L. Meanwhile, the PEC immunosensor exhibited high sensitivity, good stability, acceptable selectivity and reproducibility, indicating its potential application in environmental monitoring.
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