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A Dual Mode Photoelectrochemical Sensor for Nitrobenzene and L-cysteine Based on 3D Flower-like Cu2SnS3@SnS2 Double Interfacial Heterojunction Photoelectrode

Wang, Qiong, Zhou, Min, Zhang, Lei
Journal of hazardous materials 2019
absorption, cysteine, detection limit, electrochemistry, electrodes, fluorides, lighting, nanoparticles, nitrobenzenes, persistent organic pollutants, photochemistry, tin dioxide
In this work, 3D hierarchical Cu2SnS3@SnS2 flower assembled from nanopetals with sandwich-like Cu2SnS3-SnS2-Cu2SnS3 double interfacial heterojunction was successfully designed and synthesized on fluoride doped tin oxide (FTO) for photoelectrochemical (PEC) sensor by in situ electrodeposition p-type Cu2SnS3 nanoparticles on both inner and outer surfaces of n-type SnS2 nanopetals. The unique double interfacial heterojunction simultaneously combines 3D flower-like architectures to drastically increase the light trapping and absorption in visible-near infrared range (Vis-NIR), and dramatically inhibites the charge carrier recombination, which is crucial for boosting the PEC activity. Benefitting from the shape and compositional merits, the Cu2SnS3@SnS2 heterojunction possess dual-mode signal by controlling the electrodeposition time to manipulate the composition ratio of Cu2SnS3 and SnS2. The Cu2SnS3@SnS2/FTO electrode not only exhibits excellent photoeletro-reduction capacity for ultra-sensitive sensing trace persistent organic pollutant (nitrobenzene, NB), but also presents photoeletro-oxidization activity for high selective detection of L-cysteine (L-Cys) without any auxiliary enzyme under the light illumination. Dual mode sensor displayed superb performance for the detection of NB/L-Cys, showing a wide linear range from 100 pM to 300 μM/10 nM to 100 μM and a low detection limit (3S/N) of 68 pM/8.5 nM, respectively. Such a tunable double interfacial heterojunction design opened up new avenue for constructing multifunction PEC sensing platform.