Electrosynthesis of Ni-Co/Hydroxyapatite as a Catalyst for Hydrogen Generation via the Hydrolysis of Aqueous Sodium Borohydride (NaBH4) Solutions

To generate hydrogen from its storage as NaBH4, a catalyst was synthesized via an electrochemical method. The catalyst, Ni-Co, had hydroxyapatite as a support catalyst. The electrochemical cell consisted of a DC power supply, a carbon anode and cathode, and a bipolar membrane to separate the cell into two chambers. The current density was adjusted to 61, 91, and 132 mA/cm2. The electrolysis time was 30, 60, and 90 min. The particles produced were analyzed by XRD and SEM/EDX and tested in the hydrolysis of NaBH4 for hydrogen generation. The Ni-Co/HA catalyst test concluded that the period of time used for electrolysis during catalyst formation was positively correlated with the rate of NaBH4 hydrolysis in the production of hydrogen. The highest rate of hydrogen production was obtained using the synthesized catalyst with a current density of 92 mA/cm2. The NaBH4 hydrolysis reaction followed a first-order reaction with the rate constant of (2.220–14.117)•10-3 l/(g•min). The Arrhenius equation for hydrolysis reactions within the temperature range of 300–323 K is k = 6.5•10-6exp(-6000/T).

SELECTION OF THE METHOD OF USING THE SPENT CRACKING CATALYST

The paper considers the characteristics of a spent catalyst for the cracking of hydrocarbon feedstock. Spent catalyst formation is one of the problems for refineries. It also discusses the application of life cycle assessment to determine the environmental performance of various options for the management of spent cracking catalyst. Based on the considered use cases, providing for obtaining useful products, the best performance with the least damage to the environment is possessed by the complex processing of the spent catalyst.

Investigation of Catalyst Development from Mg2NiH4 Hydride and Its Application for the CO2 Methanation Reaction

In current study various aspects of catalyst development for the Sabatier type methanation reaction were investigated. It was demonstrated that starting from 330–380 °C Mg2NiH4 hydride heating under CO2 and H2 gas flow initiates hydride decomposition, disproportionation and oxidation. These reactions empower catalytic properties of the material and promotes CO2 methanation reaction. Detailed structural, colorimetric and thermogravimetric analysis revealed that in order to have fast and full-scale development of the catalyst (formation of MgO decorated by nanocrystalline Ni) initial hydride has to be heated above 500 °C. Another considerable finding of the study was confirmation that potentially both high grade and low grade starting Mg2Ni alloy can be equally suitable for the hydride synthesis and its usage for the promotion of methanation reactions.

Novel method for carbon nanotube growth using vapor-phase catalyst delivery

In this study, we demonstrated a novel method to grow carbon nanotubes (CNTs) by chloride-mediated chemical vapor deposition with hydride vapor-phase nucleated catalyst (HVPN). In the HVPN method, FeCl2 as a catalyst precursor was produced by an in situ chemical reaction between Fe powder and HCl gas. After the synthesis of FeCl2, CNTs were grown by supplying acetylene. We studied growth conditions for the catalyst formation process in HVPN method. High-quality CNT forests were grown by optimizing the FeCl2 synthesis conditions. This study has established the HVPN method as a novel, highly controllable way to grow CNT forests.

Direct Observation of Ni–Mo Catalyst Formation via Thermal Reduction of Nickel Molybdate Nanorods

Ni-Mo composites are known to catalyze several industrial relevant reactions involving hydrogen. Our interest is in Ni-Mo composites for hydrogen evolution reaction in alkaline anion exchange membrane water electrolyzers. We recently found that Ni-Mo composites comprise of core-shell structure where the core is metallic, rich in Ni while the shell is Mo-rich oxide. The transformation of the oxide intermediate into a core-shell architecture is studied in this work using <i>in situ</i> transmission electron microscopy. We reduced nickel molybdate nanorods in environmental transmission electron microscope and observed its transformation into the Ni-Mo catalyst composite. We further correlated these chemical transformations with the observed hydrogen evolution activity.

Direct Observation of Ni–Mo Catalyst Formation via Thermal Reduction of Nickel Molybdate Nanorods

Ni-Mo composites are known to catalyze several industrial relevant reactions involving hydrogen. Our interest is in Ni-Mo composites for hydrogen evolution reaction in alkaline anion exchange membrane water electrolyzers. We recently found that Ni-Mo composites comprise of core-shell structure where the core is metallic, rich in Ni while the shell is Mo-rich oxide. The transformation of the oxide intermediate into a core-shell architecture is studied in this work using <i>in situ</i> transmission electron microscopy. We reduced nickel molybdate nanorods in environmental transmission electron microscope and observed its transformation into the Ni-Mo catalyst composite. We further correlated these chemical transformations with the observed hydrogen evolution activity.