Search

A novel photoelectrochemical (PEC) sensor for l -cysteine was fabricated using in situ plasmonic silver nanoparticles modified hierarchically structured zinc oxide. The fabricated PEC sensor was based on Ag–S coordination chemistry and the collective oscillatory motion of electrons resulting from the coherent excitation of the “free” electrons in the conduction band of silver nanoparticles. The energetic electrons from the surface plasmon of the silver nanoparticles may be injected into the conduction band of the hierarchically structured zinc oxide and then fast transferred to the ITO electrode. However, the enhanced photocurrent produced by the plasmonic silver nanoparticles can be efficiently inhibited due to the bonding of Ag–S upon the simulated sunlight irradiation and at the bias voltage of 0.2 V. Under the optimized condition, the fabricated PEC sensor was linear with the concentration of l -cysteine in the range from 0.67 to 34.77 pmol L −1 with the detection limit of 0.21 pmol L −1 . The presence of definite concentration of conventional species did not interfere in the detection of l -cysteine and the results agreed well with those obtained by HPLC. This novel plasmonic PEC sensor has good performances in high sensitivity, good selectivity, easy operation, economy, short detection time, and portability. The strategy of localized surface plasmon resonance by in situ generation of silver nanoparticles provides an alternative way to construct a PEC sensor of l -cysteine. [ABSTRACT FROM AUTHOR]

A novel non-enzymatic and oxygen-sensitive photoelectrochemical (PEC) sensor for glucose was first constructed based on dual-functional cubic cuprous oxide. Herein, cuprous oxide acts both as an excellent catalyst for the preoxidation of glucose and as a photocathode for the PEC non-enzymatic glucose sensing. The fabricated cuprous oxide was characterized by scanning electron microscopy, X-ray diffractometry, X-ray photoelectron spectrometry, and UV–vis spectrophotometry. Under the optimized conditions, the PEC sensing was linear in its response to the logarithm of concentration of glucose in the range of 0.0005 to 6 mmol L −1 with a detection limit of 0.3 μmol L −1 . The same concentration of other common species did not interfere with the detection of glucose, and the results of the PEC sensor corresponded well with those obtained by the commercially available enzymatic glucose sensor. This novel non-enzymatic and oxygen-sensitive PEC sensor exhibited good performance with its high sensitivity, good selectivity, wide linear range, low cost, and portable features. Also it provides an alternative way for improving non-enzymatic PEC sensor of glucose. [ABSTRACT FROM AUTHOR]