Herein, the composite of vanadium pentoxide and graphene oxide (V2O5/GO) was synthesized by the solgel method. The synthesized composite V2O5/GO was characterized by X-Ray diffraction analysis and ...Raman spectroscopy. After in situ reduction of GO, the electrochemical characteristics of V2O5/rGO were analyzed by cyclic voltammetry in Mg(NO3)2 aqueous solutions. The V2O5/rGO composite showed following intercalation capacities: initially 139.1 mA h g-1 and 101.8 mA h g-1 after the 10th cycle, which along with easy, fast and low-cost synthesis, make this composite a potentially good electrode material for application in secondary aqueous magnesium-ion batteries.
Display omitted
•FeNi/rGO showed two times higher OER current density than the IrO2 electrocatalyst.•FeNi/rGO gave η10 lower for 100 mV compared to IrO2 electrocatalyst during OER.•All three FeM/rGO ...electrocatalysts showed comparable ORR catalytic activity.•Good stability of FeM/rGO electrocatalysts during ORR was noticed.
Three different iron-based electrocatalysts deposited on reduced graphene oxide (Fe/rGO, FeNi/rGO, and FeCu/rGO) were synthesized and examined for oxygen reduction and evolution reactions (ORR and OER, respectively) in alkaline media. X-ray powder diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were used for a thorough investigation of physico-chemical properties of FeM/rGO electrocatalysts. XPS analysis indicated the presence of transition metals in higher oxidation states. Onset potentials during OER were found to be 1.51, 1.64, and 1.71 V for FeNi/rGO, FeCu/rGO, and Fe/rGO, respectively. Moreover, FeNi/rGO showed the highest OER current density (∼40 mA cm−2 at 2 V), two times higher than the benchmark OER electrocatalyst, IrO2, and the lowest Tafel slope (88 mV dec-1), lower than IrO2. The somewhat better catalytic activity of Fe/rGO for ORR in alkaline media compared to FeNi/rGO and FeCu/rGO was noticed. Tafel slopes of 105, 112, and 113 mV dec-1 during ORR were found for Fe/rGO, FeCu/rGO, and FeNi/rGO, respectively. Almost constant ORR current densities during chronoamperometric measurements were noticed for Fe/rGO and FeCu/rGO indicating stable performance.
One of the most popular solutions for electrochemical energy storage is metal–air batteries, which could be employed in electric vehicles or grid energy storage. Metal–air batteries have a higher ...theoretical energy density than lithium-ion batteries. The crucial components for the best performance of batteries are the air cathode electrocatalysts and corresponding electrolytes. Herein, we present several of the latest studies on electrocatalysts for air cathodes and bifunctional oxygen electrocatalysts for aqueous zinc–air and aluminium–air batteries.
The paper analyses the ecosystemic concept of emergence and duration of alcoholism according to which the emergence and duration of alcoholism (and other addictions) is considered an illness of ...individual, family and society. It also implies a practical attitude that revealing and diagnostics of alcoholism can first start through analysis of disturbed family and social interactions and only after be searched for in medical/biological symptoms. According to this concept, identification of addiction to alcohol followed by diagnostic and therapeutic procedures make an unbreakable and continual process. It also emphasizes the fact that medical criteria for diagnostics of alcoholism are the most clear and scientifically most objective, however without providing timely diagnosis and efficient treatment. It particularly points to difficulties in process of identification of addiction to alcohol outside health institutions due to reduction of „social visibility” (mimicry of alcoholism) i.e. due to reduction of recognizability of pathological forms of behavior and alcohol drinking in family and social relations.
PDF
