Lotus seedpods biochar decorated molybdenum disulfide for portable, flexible, outdoor and inexpensive sensing of hyperin.

Biomass waste, a good candidate for advanced carbon materials for sustainable electrodes, is receiving more and more attention for high value-added materials because of its promising contribution to economic growth and sustainable development. We proposed a green co-hydrothermal approach to prepare lotus seedpods biochar (BC) decorated molybdenum disulfide (MoS2) from waste lotus seedpods and precursors of MoS2, and a portable, flexible, outdoor and inexpensive sensing platform for hyperin on the integrated flexible three-electrode using U-disk potentiostat with smartphone was successfully developed. Structure and properties of MoS2-BC were characterized, it was proved that BC improves microstructure and morphology, electronic conductivity, electrode stability and electrocatalytic properties of MoS2. Attributing to these impressive features, the detection signal of hyperin was significantly amplified by the MoS2-BC modified glass carbon electrode (GCE) in detection range of 0.01-21 µΜ with detection limit (LOD) of 5 nM. It was worth mentioning that the MoS2-BC modified screen-printed electrode (SPE) performs hyperin detection in range of 100 nM - 3 µM with LOD 50 nM (S/N = 3). The practicability of the proposed method confirmed that the portable, on-site, low-cost, and outdoor detection of hyperin was feasible and practical in comparison with traditional both electrochemical sensing and HPLC methods.

Green synthesis of kudzu vine biochar decorated graphene-like MoSe2 with the oxidase-like activity as intelligent nanozyme sensing platform for hesperetin.

It is an urgent need to exploit a potentially green, cost efficient and eco-friendly strategy for the utilization of waste kudzu vine. We developed a one-step green preparation of kudzu vine biochar (BC) decorated graphene-like molybdenum selenide (MoSe2) with the oxidase-like activity as intelligent nanozyme sensing platform for voltametric detection of hesperetin (HP) in orange peel using the in-situ hydrothermal synthesis method. The structure and properties of MoSe2-BC was characterized, and found that BC significantly improved electrochemical cycle stability, electronic conductivity, electrochemical active area, and electrocatalytic activity of MoSe2. The oxidase-like activity of MoSe2-BC was confirmed by the oxidization of the colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) to form blue products and the change of absorbance intensity of UV-vis absorption spectra. The MoSe2-BC exhibited excellent electrochemical sensing performance for the detection of HP in wide linear ranges from 10 nM to 9.5 µM with a low limit of detection of 2 nM using differential pulse voltammetric method. An emerging machine learning technique is used to realize the intelligent sensing of HP, and the performance evaluation of regression analysis was selected to evaluate this technique. This work will provide a guidance for the preparation and application of biochar decorated graphene-like nanomaterials with the oxidase-like activity and the development of intelligent nanozyme sensing platform.