Molybdenum oxide based sensors

In this review article were considered the works of electrochemical sensors modified with molybdenum oxide. The work of sensors based on molybdenum oxide was systematized, a comparison table was developed, the sensors were classified according to the purpose of use. Methods of molybdenum oxide synthesis used to modify the working electrode in electrochemical sensors were considered. The various methods have been used to synthesize molybdenum oxide, such as a thermal, hydrothermal, electrochemical, electric spark, pulsed laser method, acid condensation, electrophoretic precipitation, pulse potential precipitation. The main parameters of the molybdenum oxide modified sensors, such as the detection limit, linear range, response time, sensitivity, and other parameters were compared. As a result of studies, it was found that molybdenum oxide is selected as a modifying material in electrochemical sensors due to the unique physicochemical properties of molybdenum oxide, in particular because of mechanical strength, electrical conductivity, electro catalytic activity, crystallinity. The features of electrochemical biosensors coated with molybdenum oxide were described for the detection of important compounds in specific samples. Sensors based on molybdenum oxide have been used for detection of glucose, dopamine, ethanol, ascorbic acid, troponin-1, norepinephrine, procalcitonin, L-lactate, bromate, chlorate, E110, tartrazine, hydrochlorothiazide, human epidermal growth factor-2, lithium,sodium,potassium. This paper provides general summarized information about current aspects of research works related to electrochemical sensors based on molybdenum oxide.

Thiourea-Grafted Graphite Felts as Positive Electrode for Vanadium Redox Flow Battery

In this paper, thiourea was successfully grafted onto the surface of acid preprocessed graphite felts [sulfuric acid-treated graphite felt (SA-GFs)] by thiol-carboxylic acid esterification. The thiourea-grafted graphite felts (TG-GFs) were investigated as the positive electrode for vanadium redox flow battery (VRFB). X-ray photoelectron spectroscopy results suggested that thiourea was grafted into the surface of graphite felts. The cyclic voltammetry showed that the peak potential separation decreased by 0.2 V, and peak currents were greatly enhanced on TG-GF electrode compared with SA-GF electrode, implying improved electro-catalytic activity and reversibility of TG-GF electrode toward VO2+/VO2+ redox reaction. The initial capacity of TG-GF-based cell reached 55.6 mA h at 100 mA cm−2, 22.6 mA h larger than that of SA-GF-based cell. The voltage and energy efficiency for TG-GF-based cell increased by 4.9% and 4.4% compared with those of SA-GF-based cell at 100 mA cm−2, respectively.

Electrocatalytic Hydrogenation of CO2 to Hydrocarbons on Gold Catalyst in the Presence of Ionic Liquid

This study is aimed to investigate the electro-catalytic activity of Au supported on both CeO2 and activated carbon (AC) to convert CO2 to mixture of C1-C4 hydrocarbons in the presence of ionic liquid (IL) 1-butyl-3-methylimidazolium methylsulfonate. The studied catalyst samples were prepared by using simultaneous wet impregnation method. The sample containing 0.6 % Au showed higher electro-catalytic activity than the sample contained 0.3 % Au. Both, the average Au particles size and the transformation of layered non-uniformed semi-oval structure to flaked tiny circular like-structure were mainly responsible for the higher catalytic activity of 0.6Au-CeO2-AC sample. In addition, the overall electro-catalytic activity depends upon the applied reaction voltage. Overall, the presence of IL, the surface morphology, and average Au particles size had played a key role in the electro-catalytic conversion of CO2 to hydrocarbons.

Photo(electro)catalytic activity enhancement of PhC2Cu by Fe doping induced energy band modulation and luminescence chromism switching

This work proposed the mechanism of luminescence chromism switching and band structure modulation for enhancing the photocarriers' separation of PhC2Cu, a new kind of metal–organic coordination polymer semiconductor.