Main observation and conclusion Detection of hydrazine originated from electrochemical media has recently gained considerable attention in the sensing field. Herein, to improve electron transfer capacity, a polyoxometalate metal‐organic framework (POMOF, NENU‐3) is in‐situ nucleated onto the carboxyl functionalized reduced graphene oxide (CFG) (NENU‐3/CFG, abbreviation N3/CFG). The N3/CFG supported onto carbon cloth electrodes (CCEs) has been investigated for hydrazine detection. The amperometric results display that the POMOF/CFG to hydrazine has a broad linear range (0.09—362.5 μmol/L) and low detection limit (24 nmol/L). In addition, the POMOF/CFG‐based sensors possess good anti‐interference capability, boosted stability and feasibility. Furthermore, when applied to the detection of practical samples, acceptable relative recoveries of 96.26%—107.30% are obtained.

Transition-metal sulfide (TMS) has been regarded as the most promising alternative to construct non-noble metal catalysts in the electrochemical hydrogen evolution reaction (HER). The excellent edge activation of MoS2 and abundant catalytic active sites of Ce2S3 can be utilized as the premise of constructing heterogeneous materials for electrochemical applications. Afterward, the heteroatoms (C, N, O, and Na) have been introduced to increase the original number of active sites (the number of the S–Mo–S on the edge molecular layer of MoS2 and exposed metal active center of Ce2S3). Additionally, the heterostructure of HAs@MoS2/Ce2S3 and ordered/amorphous carbon can enhance the activity by creating defects and localized disorder fields and accelerating the charge separation/transfer from cerium (Ce) sites to molybdenum (Mo) sites. Combining the above advantages, HAs@MoS2/Ce2S3 shows promising properties toward HER not only in acidic environments with a low overpotential (147.0 mV) but also in alkaline (160.5 mV) environments.

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A hetero-phase structure of cobalt hydroxide [α/β-Co­(OH)2] in situ formed with the partly reduced graphene oxide [Co­(OH)2/PRGO] has been fabricated by a coprecipitation method. Depending on the interactions (nucleation, bonding with oxygen-rich groups, and partial conversion of GO into rGO) provided by GO, cobalt ions utilized the interactions under alkaline conditions provided by 2-methylimidazole to form hetero-phase α/β-Co­(OH)2 and maintain the unstable-structure [α-Co­(OH)2]. Beneficial to the large electrochemical active surface, rich redox active sites, and electronic transfer capability derived from hetero-phase structure [α/β-Co­(OH)2] and the partly reduced graphene oxide, the Co­(OH)2/PRGO has an extraordinary detection performance of DA: a multi-section continuous detection range (0.1 nM to 450 μM), a ultra-low limit of detection (0.078 nM, S/N = 3), and a strong anti-interference ability, coupled with an application potential in biological foods (pork) and in the body environment (serum).

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