Micro-recycling of spent Ni-Cd batteries for the obtention of electrocatalytic coatings

A micro-recycling approach was explored to produce catalytic metallic coatings for the hydrogen evolution reaction (HER). For this aim, discarded Ni-Cd batteries were employed as raw material. After dismantling the batteries, the active powder material, containing Cd and Ni compounds, was leached in a solution containing citric acid and hydrogen peroxide. The dissolved metals were electro-deposited on copper plates using a two electrodes cell at the following potentials (mV): -1900, -2000, and -2100 mV. The CdNi coating produced at -2000 mV, contained 92.6 % Cd and 7.4 % Ni. This coating was studied by cyclic voltammetry (CV) and potentiodynamic analysis in two different KOH solutions (0.1 M and 1.0 M). The CV analysis showed that the CdNi electrode was electrochemically stable in a wide operating voltage range (between oxygen evolution reaction and HER). Using an uncompensated resistance correction, the Tafel slopes for HER were obtained. The potentiodynamic analysis revealed that the synthesized CdNi electrode showed a catalytic activity for HER just 25.5 % smaller than the correspondent response of a standard pure Ni electrode. Our results serve as a proof of concept about the application of micro-recycling of spent batteries to produce sustainable electroactive catalytic materials for hydrogen production.

Titanium dioxide is Preferred for Photo-catalytic and PEC Applications: Why?

Titanium dioxide-based systems are the preferred photo-catalytic materials. Among this the commercial P25 has been consistently employed for Photo-catalytic and PEC applications. This system ( ~20% Rutile and ~80% anatase) possibly crystallizes in a core shell configuration and the relevance of this. patterning for the observed photo-catalytic or Photo-electrochemical (PEC) activity is examined.

Analysis of Liquid Organic Hydrogen Carrier Systems

Liquid organic hydrogen carriers (LOHCs) provide attractive opportunities for hydrogen storage and transportation. In this study, a detailed examination of the most prominent LOHCs is performed, with a focus on their properties and scope for successful process implementation, as well as catalytic materials used for the hydrogenation and dehydrogenation steps. Different properties of each potential LOHC offer significant flexibility within the technology, allowing bespoke hydrogen storage and transportation solutions to be provided. Among different LOHC systems, dibenzyltoluene/perhydro-dibenzyltoluene has been identified as one of the most promising candidates for future deployment in commercial LOHC-based hydrogen storage and transport settings, based on its physical and toxicological properties, process conditions requirements, availability and its moderate cost. PGM-based catalysts have been proven to catalyse both the hydrogenation and dehydrogenation steps for various LOHC systems, though base metal catalysts might have a potential for the technology.

para-Aminobenzoic acid-capped Hematite as an Efficient Nanocatalyst for Solvent-free CO2 Fixation under Atmospheric Pressure

Utilization of carbon dioxide by converting it into value-added chemicals is a sustainable remedy approach which stipulates abundant, cheap, non-toxic and efficient catalytic materials. In this study, we have demonstrated...

Simple structure descriptors quantifying the diffusion of ethene in small-pore zeolites: Insights from molecular dynamic simulations

Small-pore zeolites with 8-rings are pivotal catalytic materials to produce light olefins from non-petroleum resources employing methanol-to-olefins or syngas-to-olefins processes. The constraints of cage openings on the diffusion of light...

The degradation of methylene blue by microcubes catalyst -Fe2O3 via heterogenous Fenton process

Cubic Fe2O3 was synthesized in a facile approach by annealing molecular organic framework Prussian Blue (PB) at 350oC, 550oC, and 650oC. The final product was characterized by IR, Raman and XRD spectroscopic methods illustrating the presence of pure a-Fe2O3. SEM images of this material revealed a homogeneous morphology of microcube Fe2O3 with a size of about 500 nm. The catalytic activity of cubic Fe2O3 was investigated on the degradation of methylene blue in a heterogeneous Fenton system. It was shown that the thermally oxidative decomposition of PB at 550oC has resulted in porous Fe2O3 which exhibited highest MB degradation efficiency. In the presence of 0.5 M H2O2 and 0.3 g/L Fe2O3 at pH = 3.59, 50 ppm MB in studied solution has been removed at a rate constant of 0.0398 min-1, which is comparable with other analogous catalytic materials.

Case Studies in Biogas Production from Different Substrates

The present paper involves applicative research in the field of biogas production with the accent on small laboratory scale installations built for biogas production, preliminary testing of substrate for biogas production and combustion applications for biogas-like mixtures. The interconnected aspect of the presented material involves cumulative expertise in multidisciplinary fields of interest and continuous development of possibilities to determine the energetic potential of substrates subjected to biodegradable fermentation conversion for further applications. The research analyzed the combustion behavior of biogas with different methane/carbon dioxide ratio without and in the presence of specific catalysts. Also, laboratory analysis on biomass substrates for determining their physical and chemical potential for different applications was performed. The main conclusions are drawn revolve around the untapped potential of the different types of biomasses that are not commonly used in the production of renewable energy carriers, like biogas, and also the potential use of residual biomass in combustion processes for an enclosed life cycle from cradle to the grave. The study involving the use of catalysts in biogas combustion processes present possible solutions which can be developed and implemented for increasing the combustion quality by using relatively cost-effective materials for the production of catalytic materials.