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This paper reports the preparation and electrochemical study of new glassy carbon electrode (GCE) bulk-modified with synthesized hybrid materials: Pt and MoO2 nanoparticles deposited on the multi-walled carbon nanotubes (MWCNTs). The results of electrochemical study of commercial GCE and electrodes modified with Pt?MWCNT and MoO2?MWCNT were obtained by cyclic voltammetry in K4Fe(CN)6 and NaOH solutions. Morphology and structure of the synthesized hybrid materials were analysed using the method of high resolution transmission electron microscopy, indicating the presence of well dispersed nanoparticles of Pt and MoO2 over MWCNT network. The results of the electrochemical study show that the capacitance of electrode modified with MoO2?MWCNT and Pt?MWCNT is 62?65 times higher than the capacitance of the commercial GCE. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 451-03-68/2020-14/200124]

Excellent mechanical, electrical and magnetic properties of carbon nanotubes (CNT) make CNTs a promising material for the development of electrochemical sensors. Pesticides are very important for an increase in crop yields. However, the intensive use of pesticides can lead to the accumulation of their remains, thus creating a severe problem and risk to human and environmental health. Those are the reasons why the monitoring of pesticides in the environment is extremely important. For that purpose, electrochemical sensors based on carbon nanotubes were designed, and their main aim is pesticide monitoring at environmental samples. A review of the recent studies of environmental monitoring of pesticides using electrochemical sensors based on carbon nanotubes is presented.

Magnesium silicate hydrate (M-S-H) was prepared via one-pot hydrothermal synthesis and electrophoretically deposited (EPD) onto stainless steel substrate (Type 304), varying different process parameters. The optimal conditions for the EPD process were found to be as follows. A stable suspension of material was achieved using isopropanol containing 1% water as dispersing medium and Mg-nitrate as charging additive. The best coating was obtained after three successively repeated EPD processes at a voltage of 30 V, accompanied by drying at room temperature between each EPD cycle. The coating showed a thickness of 31 µm and very smooth surface. After calcination at 900 °C coating retains its adherence to the substrate but undergoes a structural transformation from poorly crystallized M-S-H to well-crystallized clinoenstatite phase which is known for its biocompatibility. As a result, it densifies and shrinks giving grainy and slightly rough surface. Structural properties and parameters of the magnesium silicate hydrate (M-S-H) and clinoenstatite were acquired by XRD technique, while morphology was examined by the analysis of SEM micrographs. This study demonstrates that: i) M-S-H can be synthesized through simple hydrothermal route starting from simple, low-cost precursors, ii) EPD process is an effective technique for deposition of M-S-H materials onto stainless steel and iii) inosilicate mineral (clinoenstatite) can be successfully obtained from M-S-H by calcination at 900 °C.