Synchronous electrochemical detection of dopamine and uric acid by a PMo12@MIL-100(Fe)@PVP nanocomposite.

In this work, a noble-metal-free composite electrode was prepared based on PMo12O403- (PMo12), C9H5FeO7 (MIL-100(Fe), a Fe-based metal organic framework) and polyvinylpyrrolidone (PVP), and served as a high performance electrochemical sensor for synchronous detection of dopamine (DA) and uric acid (UA). The PMo12@MIL-100(Fe)@PVP composite electrode was fabricated by a in-situ hydrothermal method. Thanks to the synergistic effect of three active components (PMo12, MIL-100 and PVP), the electrode possesses large specific surface area and high electrical conductivity and therefore it shows high electrocatalytic oxidation performance of DA and UA with a spacing of 0.146 V between the two peak positions. These benefits of the electrode enable its electrochemical sensor to synchronously detect of DA and UA. Namely, the linear ranges can achieve 1-247 µM for DA and 5-406 µM for UA. Meanwhile, the detection limits are 0.586 µM for DA and 0.372 µM for UA. Moreover, the sensor can be applied to simultaneous determination of UA and DA in human serums with satisfactory recovery values.

In situ coupling of a Co-Mo bimetallic sulfide derived from [CoMo12O40]6- clusters showing highly efficient electrocatalytic hydrogen evolution.

The hydrogen evolution reaction (HER) is important for "green" hydrogen production from water electrolysis. Nowadays, there is an urgent need to construct highly efficient electrocatalysts to boost the HER and achieve hydrogen production. Herein, we present the preparation of a new composite Co-Mo bimetallic sulfide supported on carbon cloth (MoS2/CoS2/CC) via a one-pot hydrothermal sulfurization strategy using (C3H5N2)6[CoMo12O40]·10H2O (CoMo12) as a metal source and thiourea as a sulfur source. The obtained MoS2/CoS2/CC catalyst exhibited outstanding HER ability, with an overpotential of 69 mV when the current density is 10 mA cm-2 in KOH solution, showing comparable performance with those of the advanced Pt/C electrodes tested under the same conditions. Additionally, the results of XRD after the catalytic reaction showed that the electrode had excellent stability in the electrolyte of 1.0 M KOH.

In situ hierarchical encapsulation of bimetallic selenides into honeycomb-like nitrogen doped porous carbon nanosheets for highly sensitive and selective guanosine detection.

An innovative electrochemical nanocomposite for the detection of guanosine (Gua) was proposed by in situ encapsulation of nickel-iron bimetallic selenides confined into honeycomb-like nitrogen doped porous carbon nanosheets, denoted as (Ni,Fe)Se2/N-PCNs. The porous carbon nanosheets were prepared by utilizing nickel-iron layered double hydroxide (Ni-Fe LDH) as the substrate and zeolitic imidazolate frameworks (ZIF-67) nanocrystals as the sacrificial templates via hydrothermal synthesis, followed by a process of acid etching and pyrolysis selenylation. Interestingly, the nickel-ferric bimetallic selenides material (Ni,Fe)Se2, is rarely fabricated successfully using selenylation treatment, which is a highly conductive and robust support to promote the electron transport. Meanwhile, the obtained (Ni,Fe)Se2/N-PCNs have the favorable architectural features of both unique three-dimensional (3D) porous structural and hierarchical connectivity, which are expected to provide more active sites for electrochemical reactions and ease of electron, ion, and biomolecule penetration. Benefiting from the inherent virtues of its composition, together with unique structural advantages, the (Ni,Fe)Se2/N-PCNs possess ideal sensing properties for guanosine detection with a low detection limit of 1.20 × 10-8 M, a wide linear range of 5.30 × 10-8 ~ 2.27 × 10-4 M and a good stability. Superb selectivity for potential interfering species and superb recoveries in serum suggests its feasibility for practical applications.