Dopamine is an important neurotransmitter that has a crucial impact on the physiological health of the human body. Consequently, it is necessary to establish a highly selective and sensitive method for the determination of dopamine levels in serum. In this work, g-C 3 N 4 and BiPO 4 /BiOCl (BPCl) were used as optoelectronic materials to construct a novel dopamine photoelectrochemical sensor. Moreover, the optoelectronic materials were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy and steady-state fluorescence spectroscopy . Meanwhile, the photoelectrochemical performance of the modified electrodes with different materials was investigated, and the results showed that BPCl/C 3 N 4 /GCE has excellent photoelectrochemical performance. Concomitantly, the dopamine photoelectrochemical sensor also has a wide detection range (0.05–10 μM) and limit of detection (LOD = 0.023 μM). Furthermore, it has good reproducibility, selectivity and stability, which can be used in the actual sample detection of serum.
BiPO 4 /BiOCl p-n heterojunction photocatalysts were successfully prepared by a facile in situ chemical transformation method with the aim of degrading rhodamine B under simulated sunlight. X-ray diffraction, field emission scanning electron microscopy , ultraviolet–visible diffuse reflectance spectroscopy , photoluminescence , and electrochemistry tests were used to characterized the structure, morphology, optical properties , and inhibited recombination of photoinduced charges. BiPO 4 /BiOCl composites exhibited significantly higher photocatalytic activity for the degradation of rhodamine B than pure BiOCl, and the apparent rate constant is 3.18 times higher than that of BiOCl. The significantly increased photocatalytic activity of the BiPO 4 /BiOCl composites can be ascribed to the formation of a p-n heterojunction , which can effectively boost the separation of photoinduced electron-hole pairs during the photocatalytic process. Additionally, the main active species were investigated and a plausible mechanism is proposed.
Catechol is a phenolic environmental pollutant that is highly toxic to living organisms and is released into the environment, where it is difficult to degrade in the ecosystem, thereby contaminating the environment and groundwater. Here, P(NIPAM-co-BMA)/BiPO 4 /BiOCl/MWCNTs nanocomposites were synthesized, and a temperature-controlled "on/off" electrochemical sensor was constructed. In addition, the P(NIPAM-co-BMA)/BiPO 4 /BiOCl/MWCNTs/GCE sensor shows good thermal sensitivity and electrochemical detection of catechol. Reproducible "on/off" switching on the CVs curve can be achieved by controlling the temperature of the solution. Under optimal conditions, the sensor was able to detect catechol in the linear range of 0.5–86.51 μM with a limit of detection of 0.2 μM (S/N = 3). Satisfactory results were obtained for the detection of natural environmental samples (tap water). In addition, the redox mechanism and electrochemical reaction sites of catechol were investigated by scanning rates. This work demonstrates for the first time the combination of temperature-sensitive polymers, bismuth-based compounds and multi-walled carbon nanotubes as electrochemical sensors for the detection of catechol, opening a new window for the sensitive detection of catechol. At the same time, the constructed switch-like electrochemical sensors can be better applied to different special scenarios.
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