Abiotic, Hybrid, and Biological Electrocatalytic Materials Applied in Microfluidic Fuel Cells: A Comprehensive Review

This article provides an overview of the work reported in the past decade in the field of microfluidic fuel cells. To develop appropriate research, the most commonly used electrocatalytic materials were considered and a new classification was proposed based on their nature: abiotic, hybrid, or biological. This classification allowed the authors to discern the information collected. In this sense, the types of electrocatalysts used for the oxidation of the most common fuels in different environments, such as glucose, ethanol, methanol, glycerol, and lactate, were presented. There are several phenomena presented in this article. This information gives an overview of where research is heading in the field of materials for electrocatalysis, regardless of the fuel used in the microfluidic fuel cell: the synthesis of abiotic and biological materials to obtain hybrid materials that allow the use of the best properties of each material.

Global Situation of Bioremediation of Leachate-Contaminated Soils by Treatment with Microorganisms: A Systematic Review

This systematic review presents the current state of research in the last five years on contaminants in soils, especially in leachates from solid waste landfills, with emphasis on biological remediation. In this work, the pollutants that can be treated by microorganisms and the results obtained worldwide were studied. All the data obtained were compiled, integrated, and analyzed by soil type, pollutant type, bacterial type, and the countries where these studies were carried out. This review provides reliable data on the contamination of soils worldwide, especially soils contaminated by leachate from municipal landfills. The extent of contamination, treatment objectives, site characteristics, cost, type of microorganisms to be used, and time must be considered when selecting a viable remediation strategy. The results of this study can help develop innovative and applicable methods for evaluating the overall contamination of soil with different contaminants and soil types. These findings can help develop innovative, applicable, and economically feasible methods for the sustainable management of contaminated soils, whether from landfill leachate or other soil types, to reduce or eliminate risk to the environment and human health, and to achieve greater greenery and functionality on the planet.

Composite Sulfonated Polyether-Ether Ketone Membranes with SBA-15 for Electrochemical Energy Systems

The aim of this work is the evaluation of a Sulfonated Poly Ether-Ether Ketone (S-PEEK) polymer modified by the addition of pure Santa Barbara Amorphous-15 (SBA-15, mesoporous silica) and SBA-15 previously impregnated with phosphotungstic acid (PWA) fillers (PWA/SBA-15) in order to prepare composite membranes as an alternative to conventional Nafion^® membranes. This component is intended to be used as an electrolyte in electrochemical energy systems such as hydrogen and methanol Proton Exchange Membrane Fuel Cell (PEMFC) and Electrochemical Hydrogen Pumping (EHP). The common requirements for all the applications are high proton conductivity, thermomechanical stability, and fuel and oxidant impermeability. The morphology of the composite membranes was investigated by Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy (SEM-EDS) analysis. Water Uptake (Wup), Ion Exchange Capacity (IEC), proton conductivity, methanol permeability and other physicochemical properties were evaluated. In PEMFC tests, the S-PEEK membrane with a 10 wt.% SBA-15 loading showed the highest performance. For EHP, the inclusion of inorganic materials led to a back-diffusion, limiting the compression capacity. Concerning methanol permeability, the lowest methanol crossover corresponded to the composites containing 5 wt.% and 10 wt.% SBA-15.

Glycerol electro-oxidation in alkaline media using Pt and Pd catalysts electrodeposited on three-dimensional porous carbon electrodes

Electrodeposition of Pd and Pt electrocatalysts on the entire structure of carbon paper and carbon nanofoam enhances the glycerol electro-oxidation.

An electrokinetic-combined electrochemical study of the glucose electro-oxidation reaction: effect of gold surface energy

Electrokinetic analysis demonstrates the effect of glucose adsorption on gold surfaces in the glucose electro-oxidation mechanism.

Copper-palladium core-shell as an anode in a multi-fuel membraneless nanofluidic fuel cell: toward a new era of small energy conversion devices

A membraneless nanofluidic fuel cell with flow-through electrodes that works with several fuels (individually or mixed): methanol, ethanol, glycerol and ethylene-glycol in alkaline media is presented. For this application, an efficient Cu@Pd electrocatalyst was synthesized and tested, resulting outstanding performance until now reported, opening the possibility of power nano-devices for multi-uses purposes, regardless of fuel re-charge employed.

A nanofluidic direct formic acid fuel cell with a combined flow-through and air-breathing electrode for high performance

The use of three-dimensional flow-through nanoporous electrodes and the merging of a flow-through and air-breathing cathode were explored and successfully applied in a formic acid air-breathing nanofluidic fuel cell. The effects of fuel concentration, reaction stoichiometry and catalyst mass loading were investigated, resulting in power densities ranging from 28 to 100 mW cm(-2).

Hybrid microfluidic fuel cell based on Laccase/C and AuAg/C electrodes

A hybrid glucose microfluidic fuel cell composed of an enzymatic cathode (Laccase/ABTS/C) and an inorganic anode (AuAg/C) was developed and tested. The enzymatic cathode was prepared by adsorption of 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and Laccase on Vulcan XC-72, which act as a redox mediator, enzymatic catalyst and support, respectively. The Laccase/ABTS/C composite was characterised by Fourier Transform Infrared (FTIR) Spectroscopy, streaming current measurements (Zeta potential) and cyclic voltammetry. The AuAg/C anode catalyst was characterised by Transmission electron microscopy (TEM) and cyclic voltammetry. The hybrid microfluidic fuel cell exhibited excellent performance with a maximum power density value (i.e., 0.45 mW cm(-2)) that is the highest reported to date. The cell also exhibited acceptable stability over the course of several days. In addition, a Mexican endemic Laccase was used as the biocathode electrode and evaluated in the hybrid microfluidic fuel cell generating 0.5 mW cm(-2) of maximum power density.

Full factorial design applied to the synthesis of Pd–Ag nanobars by the polyol method and the perspective for ethanol oxidation

Full factorial design methodology was applied for the first time to the synthesis and optimization of palladium–silver nanobars using the polyol process as reducer.

AuPd/polyaniline as the anode in an ethylene glycol microfluidic fuel cell operated at room temperature

AuPd/polyaniline was used for the first time, for ethylene glycol electrooxidation in a microfluidic fuel cell operated at room temperature.

Effect of metal content on the electrocatalytic activity of AuxPdy mixtures and their use in a glucose membraneless microfluidic fuel cell

Performance increase of a glucose membraneless microfluidic fuel cell using Au₆₀Pd₄₀ material electrodeposited on the anodic compartment.