Chromium(III) oxide

About: Chromium(III) oxide is a research topic. Over the lifetime, 163 publications have been published within this topic receiving 2526 citations. The topic is also known as: green oxide of chromium & green chromium oxide.

Selective impedance based gas sensors for hydrocarbons using ZSM-5 zeolite films with chromium(III)oxide interface

Abstract: Highly sensitive and selective hydrocarbon gas sensors were obtained by covering gold interdigital capacitor (IDC) electrodes with platinum-doped Na-ZSM-5 zeolite thick films. A chromium(III) oxide layer between gold and zeolite is responsible for the new outstanding sensor effect. Such Au/Cr2O3/zeolite interfaces might be formed by diffusion of the chromium bonding agent through the gold electrode during annealing of the zeolite layer and subsequent oxidation or depositing of additional Cr2O3 layers on top of the electrodes by thin-film techniques. Impedance spectra consist of high-frequency semicircles and low-frequency Warburg-like contributions. The impedance at a fixed frequency in the low-frequency region depends very selectively on the hydrocarbon concentration in wet oxygen/nitrogen mixtures. Very low or zero cross-sensitivities were found towards CO, H2, NO, and CO2 gases. Different substrate materials and thicknesses of the Cr2O3 layer were compared. A preliminary simple equivalent circuit model is presented.

A nanostructured chromium(III) oxide/tungsten(VI) oxide p–n junction photoanode toward enhanced efficiency for water oxidation

Abstract: A nanostructured chromium(III) oxide/tungsten(VI) oxide (Cr2O3/WO3) p–n junction photoanode is established here. It is prepared by depositing Cr2O3 nanoparticles onto WO3 nanosheet arrays. The formation of a p–n junction is confirmed by the Mott–Schottky plot and photocurrent measurements. Electrochemical and spectroscopic methods indicate that the recombination rate of photogenerated charges becomes lower in this photoanode. Consequently, its onset potential shifts negatively by about 0.1 V and photocurrent density increases from 0.7 to 1.8 mA cm−2 at 1.8 V vs. RHE. The incident photon-to-current efficiency (IPCE) also shows a one-fold improvement. In addition, the construction of the p–n junction leads to an increase of faradaic efficiency (holes to oxygen) from 73.9% to 92.0%, which is attributed to the suppression of side reactions in water oxidation. This work will provide new inspiration for improving the performance of WO3 and other photoanodes.

Synthesis of Chromium(III) Oxide Nanoparticles by Electrochemical Method and Mukia Maderaspatana Plant Extract, Characterization, KMnO4 Decomposition and Antibacterial Study

Abstract: Chromium oxide nanoparticles were synthesized by the reduction of potassium dichromate solution with Mukia Maderaspatana plant extract In electrochemical methods, Cr2O3 nanoparticles were synthesized by two ways, using platinum (Pt) electrodes and K2Cr2O7 solution with H2SO4 as medium in the first case And chromium doped platinum electrode (Pt/Cr) in presence of NaHCO3 solution in second case The resulting Cr2O3 nanoparticles were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-VIS absorption and Fourier-transform infrared (FTIR) spectroscopy The enhancing influence of Cr2O3 nanoparticles as a catalyst for the decomposition of KMnO4 has been studied The antibacterial effect of Cr2O3 nanoparticles against E coli was investigated These particles were shown to have an effective bactericide

Determinação de rotina do crômio em fezes, como marcador biológico, pelo método espectrofotométrico ajustado da 1,5-difenilcarbazida

Abstract: This work aims at adjusting the spectrophotometric method of 1,5-diphenylcarbazide for the determination of chromium in feces, as a biological marker. Factors that could interfere with the transformation of chromium (III) into chromium (VI) were tested, as the metal recovery, the sample amount, the amount and the order of use of the oxidant acids of the wet digestion, digestion temperature and digestion time, loss of chromium by volatilization as chromyl chlorid. However the interference of these factors were not statistically determined. In the adjusted method, the sample is classically digested by nitric/perchloric acid mixture leading to the oxidation of chromium (III) to chromium (VI), and an aliquot of the diluted extract is used for reaction with 1,5-diphenylcarbazide; absorbance was measured at 550nm, using 1cm path length optical cuvettes. Potassium dichromate was used as a standard substance to obtain the standard curve ranging from 0.25mg.mL-1 to 2.5mg.mL-1 of Cr2O3 (1mg Cr2O3 o 1.9355mg K2Cr2O7).