A Facile Approach of Fabricating Bifunctional Catalysts for Redox Applications by Uniformly Immobilized Metallic Nanoparticles on NiCr LDH.

This study discloses the development of NiCr LDH, Ag@NiCr LDH, and Pd@NiCr LDH bifunction catalysts using a hydrothermal coprecipitation method followed by sol immobilization of metallic nanoparticles. The structures and morphologies of the synthesized nanocomposites were analyzed using FTIR, XRD, XPS, BET, FESEM-EDX, and HRTEM. The catalytic effectiveness of the samples was evaluated by tracking the progression of NaBH4-mediated nitrobenzene (NB) reduction to aniline and CO oxidation using UV-visible spectrophotometry and an infrared gas analyzer, respectively. Pd@NiCr LDH displayed much higher performance for both reactions than the bare NiCr LDH. The catalyst Pd@NiCr LDH showed robust catalytic activity in both the oxidation of carbon monoxide (T50% (136.1 °C) and T100% (200.2 °C)) and NaBH4-mediated nitrobenzene reduction (98.7% conversion and 0.365 min-1 rate constant). The results disclose that the Ni2+@ Cr3+/Cr6+ @Pd° ion pairs inside the LDH act as a charge transfer center and hence significantly enhance the catalytic performance. As a result, this research offers the novel NiCr LDH catalyst as a bifunctional catalyst for air depollution control and the organic transformation process.

A Process for Hydrogen Production from the Catalytic Decomposition of Formic Acid over Iridium-Palladium Nanoparticles.

The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium-palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in the presence of 1% iridium over activated charcoal led to a 43% conversion of formic acid to hydrogen at room temperature after 4 h. Increasing the temperature to 60 °C led to further decomposition and an improvement in conversion yield to 63%. Dilution of formic acid from 0.5 to 0.2 M improved the decomposition, reaching conversion to 81%. The reported process could potentially be used in commercial applications.

Biogenic-Mediated Synthesis of the Cs2O-MgO/MPC Nanocomposite for Biodiesel Production from Olive Oil.

In this work, a biogenic-mediated approach is successfully used to synthesize a novel heterogeneous Cs2O-MgO/MPC basic nanocomposite. For the first time, the established technicality employs pomegranate seed extract that gives a green capping fuel and reducing mediators during an aqueous solution combustion process of metal ion precursors. The synthesized nanocomposites were identified by X-ray diffraction, Fourier transform infrared, N2 isotherms, field emission scanning electron microscopy, and CO2-TPD analyses. The transesterification process of olive oil was used to evaluate the catalytic performance. The nanocomposite displayed outstanding catalytic efficiency stemming from the boosting of the reactant and product diffusion. The transesterification activity and the optimization design were assessed by applying the response surface methodology. Based on the experimental tests, the finest experimental conditions with a biodiesel yield of 96.1% are 4 h, 4% catalyst amount, an oil/methanol ratio of 1:15, and a temperature of 65 °C. The predicted optimal conditions based on the statistical model are 6 h contact time, 5.2 % catalyst dose, 65 °C reaction temperature, and 1:15 oil/methanol molar ratio, attaining a biodiesel yield of 95.18%. The catalyst reusability has been performed almost continuously up to four cycles, with no loss of the active constituents. The obtained biodiesel demonstrated characteristics close to those of international standards of biodiesel. Besides, the process employed in this study demonstrated significant potential for further development and commercialization and is cheaper than the refined vegetable oil used in traditional approaches of biodiesel manufacturing.