posted on 2017-11-07, 00:00authored byYuhan Zhu, Zuwei Xu, Kai Yan, Haibo Zhao, Jingdong Zhang
CuO–Cu2O heterojunction
was synthesized via a one-step flame spray pyrolysis (FSP) process
and employed as photoactive material in construction of a photoelectrochemical
(PEC) sensing device. The surface analysis showed that CuO–Cu2O nanocomposites in the size less than 10 nm were formed and
uniformly distributed on the electrode surface. Under visible light
irradiation, the CuO–Cu2O-coated electrode exhibited
admirable cathodic photocurrent response, owing to the favorable property
of the CuO–Cu2O heterojunction such as strong absorption
in the visible region and effective separation of photogenerated electron–hole
pairs. On the basis of the interaction of l-cysteine (l-Cys) with Cu-containing compounds via the formation of Cu–S
bond, the CuO–Cu2O was proposed as a PEC sensor
for l-Cys detection. A declined photocurrent response of
CuO–Cu2O to addition of l-Cys was observed.
Influence factors including CuO–Cu2O concentration,
coating amount of CuO–Cu2O, and applied bias potential
on the PEC response toward l-Cys were optimized. Under optimum
conditions, the photocurrent of the proposed sensor was linearly declined
with increasing the concentration of l-Cys from 0.2 to 10
μM, with a detection limit (3S/N) of 0.05 μM. Moreover,
this PEC sensor displayed high selectivity, reproducibility, and stability.
The potential applicability of the proposed PEC sensor was assessed
in human urine samples.