Electrochemical models can accurately describe lithium-ion battery behavior, but their high computational burden limits their use in real-time embedded applications. Therefore, they can be simplified to reduced models, such as the single particle model (SPM) often used for state estimation. However, low-order SPM intrinsic limitations, including inaccuracies in estimation of electrode open-circuit potential (OCP) and electrolyte overpotential, have to be overcome. Two significant improvements in SPM have been proposed while preserving its low-order formulation, its physical meaning, and its suitability for observer design: (1) a low-order direct approximation method was applied to the solid diffusion transcendental transfer function, enabling accurate electrode OCP estimation; (2) electrolyte diffusion dynamics was included using a finite difference method with low-order discretization, leading to electrolyte concentration gradients and related overpotentials. The proposed model with a total order of 21, was tested on a single 40 Ah LTO-NMC cell in two profiles emulating suburban transport. Compared to experimental data, the root mean square (RMS) cell voltage errors were only a few millivolts for both profiles. Moreover, compared to the original SPM, improvement in solid diffusion dynamics reduced RMS voltage errors by 20 %, and inclusion of electrolyte dynamics allowed further RMS error reduction by 40 %.

A direct hybrid power source between fuel cells and batteries was proposed for a smaller and lighter electric vehicle, specifically designed for urban and suburban transport. By eliminating the DC/DC power converter, the system structure is simplified, its energy losses, weight and cost can also be reduced. The feasibility of this architecture was validated at a small scale by directly hybridizing a stack of five proton exchange membrane fuel cells and a single lithium-ion battery under a (sub)urban driving cycle. Power and energy contributions of the fuel cell stack and the battery were determined. A natural power sharing was observed: the fuel cell provided a regular power output with very small fluctuations, as it would be with power converters, while the battery flexibly responded to rapid transients, allowing the hybrid power source to meet the full power demand. Moreover, the fuel cell provided more power than the mean load demand, with the excess mainly recharging the battery. This confirms the appropriate sizing of the hybrid power source: when coupled, the fuel cell recharges the battery while continuously supplying power to the load.

Ferredoxin-NADP+ reductase (FNR) is an efficient and selective biocatalyst to continuously regenerate the NADPH cofactor consumed in biomolecular synthesis for the chemical and pharmaceutical sectors. In this work, FNR from Chlamydomonas reinhardtii was applied to electrochemical regeneration of the nicotinamide cofactors, by combining this enzymatic catalyst in a flow reactor with the oxidation of hydrogen, a clean source of electrons and protons. FNR was immobilized on the surface of oxidized multi-walled carbon nanotubes, which allowed maintaining its activity for over six days under high flow rate. Surprisingly, this modified FNR electrode was effective not only in regenerating NADPH but also NADH. The cofactor regeneration was then applied to the NADH-dependent production of lactate from pyruvate, using L-lactate dehydrogenase (LDH) in the presence of low NAD+ concentration (10 mu M). Both FNR and LDH enzymes were immobilized in the bioelectrochemical system that achieved a remarkable total turnover number (TTN) of 104 for the nicotinamide cofactor and a faradaic efficiency higher than 80 %.

From a highly valuable metal blend produced from electronic waste, precious metals could be selectively beneficiated by combined electrochemical leaching and electrodeposition in deep eutectic solvents. For the case of silver presented in this work, 25 µm thick deposits have been prepared from ethaline 1:2 and propeline 1:3 deep eutectic solvents in a lab-scale stirred cell at various current densities in a dry atmosphere, with faradaic yields close to 100

This study investigates urea removal from wastewater using zinc-based electrocoagulation method, supported by Gradient Boosting Regressor modeling. The highest urea removal of 42% was obtained for 1.2 g/L initial urea concentration, 22 mA/cm2 current density, and a pH solution of 10, while natural pH (approximate to 7.50) gave 30%. By applying the optimum conditions 27% of urea was removed from real hospital effluent. Application of GBR model leveraging Artificial Intelligence (AI) demonstrated a high predictive accuracy (R2 = 0.9825, RMSE = 0.01666) with experimental results. Treatment combination processes were investigated: Chemical Coagulation-Electrocoagulation achieved 35% efficiency, while two EC cycles yielded 45%. Electrocoagulated sludge characterization by scanning electron microscope/energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction analysis revealed surface irregularities as well as the presence of zinc, carbon, nitrogen, and sodium. These findings confirm the treatment's effectiveness in removing urea and support the safe valorization and reuse of the sludge. EC proves effective and cost-efficient for industrial-scale implementation.

For urban or suburban transport, the power demand of a personal car does not exceed 30 kW/ton, far below the power offered by regular cars designed for any ride. Moreover, it was formerly shown that the above power could be attained by a 10 kW fuel cell directly hybridized to a supercapacitor string able to deliver a 20 kW power peak. This theoretical fact, corresponding to low resource demand in the car manufacturing, was validated up to ½ scale on the bench. Within a research project in University of Lorraine, the target is to validate the low-resource demanding concept in a real hydrogen electric vehicle (fuel cell range extender Renault Kangoo) and to examine related aspects by combining engineering sciences to social and human sciences and economics. After reminding the former validation on a bench, the paper describes current work on how the electrical power is managed in the Renault H2 ZE Kangoo, by characterization of the fuel cell and thorough analysis of the transients of electrical and non-electrical variables available in the vehicle in various rides. Besides, risks and life cycle analysis of a one-ton hybrid vehicle have been evaluated in comparison with other 30 kW vehicles powered by either a fuel cell, or batteries or an internal combustion engine. Finally, social acceptability of the fuel cell cars by regular citizens is presented, revealing a positive opinion at fuel cells and hydrogen, however with a moderate readiness to its acquisition.

We consider the potentiality of propeline, a DES with a lower toxic nature than ethaline, for the electrometallurgy of silver.

The degradation of two textile dye molecules was studied using photochemical processes, both in the absence and presence of light. Various methods were employed, including photolysis/UV, combined H2O2/UV photolysis, Fe2+/UV treatment, Photo-Fenton/UV at 350 nm and Photo-Fenton with solar irradiation. The decolorization efficiency of dyes in aqueous solution was evaluated for two specific dyes: Bromothymol Blue (BTB) and Methyl Green (MG). These experiments were carried out in batch mode. The results demonstrated a synergy between light irradiation and the presence of Fenton's reagents, such as hydrogen peroxide and divalent iron. In addition, it was demonstrated that direct solar irradiation can be used without specific devices to achieve high efficiency at low cost. In the first part, we checked the impact of the various operating parameters. Reaction efficiencies were compared for the same system in the dark and under the assistance of an artificial or solar light source. In the second part, we studied the parameters of the Photo-Fenton process, such as the initial pH of the solution, the initial concentrations of oxidant, iron catalyst, and dye under irradiation from either light source. Whereas the mere photolysis without Fenton's reagents allowed decolorization yields below 26 %, addition of the oxidant (H2O2) or the catalyst (Fe(II) species amplified the treatment efficiency. However, the presence of both H2O2 and Fe(II) under light irradiation was shown synergetic with yields ranging from 72 to 85 % depending on the dye worked and the light source: because of its broader spectrum in the UV domain, solar irradiation led to the highest decolorization yields. The above results were obtained for well-defined proportions of dye and reagents: for a 20 mg/l dye solution, Fe(II) catalyst concentration equal to 10-3 M, peroxide concentration of 5.10-2 M and a pH of 3. These conditions allowed optimal production of OH radicals, allowing high efficiency in systems using solar irradiation.

The effectiveness of hybrid bioelectrocatalytic flow reactor with NADH cofactor regeneration by an immobilized rhodium mediator (i.e., (2,2 & PRIME;-bipyridyl)(pentamethylcyclopentadienyl)-rhodium chloride complex, [Cp*Rh(bpy) Cl]+) was previously demonstrated for the example of pyruvate bioconversion with NAD+ concentration as low as 10 & mu;M. This paper presents a model of the complete hybrid process for NADH-based bioconversion, in view to identifying possible rate control by one of these phenomena depending on the operating conditions. The various phenomena involved in the 16 cm2 bioelectrocatalytic cell, have been separately investigated, namely electrochemical reduction of immobilized Rh(III) complex, NADH regeneration by action of the formed Rh(I), mass transfer to the electrode and enzymes deposited layers, and lactate dehydrogenase-catalyzed pyruvate reduction by action of NADH. The kinetics of the redox process deviates from a first-order process with respect to NAD+, resulting in a far larger reaction rate constant for redox NADH regeneration with concentrations below 100 & mu;M. Besides, simulations showed that in this concentration domain, far larger mass transfer coefficients to the carbon layers, had to be used to simulate the high production rate and turnover values reported: process intensification in the bioelectrochemical system allowed by the proximity of the two reactional layers, may explain far larger mass transfer coefficients.

Nitrogen-doped graphenic materials (N-Gr) are attracting increasing interest in the field of electrocatalysis, where their applications as noble metal-free catalysts or as catalyst supports are explored worldwide. Solvothermal-based processes are an efficient way to produce large quantities of N-Gr, without compromising their valuable properties. Reported in earlier publications, our elaboration route is based on a solvothermal reaction between various organic alcohols, e.g. cyclohexanol, ethanolamine, 1(2-hydroxyethyl)piperidine, and metallic sodium, followed by a pyrolysis treatment under nitrogen flow. Rarely investigated in the literature mainly due to their complex mechanisms, the understanding of such processes opens many paths to tailor the properties of N-Gr, leading to high porosity (>2200 m2/g), good crystallinity, high purity, etc. The present article focuses on the influence of the solvothermal reaction experimental parameters on the final N-Gr, i.e. temperature, pressure, and sodium content. The elaborated materials are studied through multi-scale and complementary characterization techniques, i.e. Raman spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, N2 adsorption at 77 K. An overview of the whole process follows the experimental part, giving quick access to optimized experimental parameters depending on the desired N-Gr properties, e.g. yield, crystallinity or porosity. By way of illustration, some trends were evidenced, such as (i) the larger conversion rate of solvent into crystalline carbon material as the reaction temperature is increased (300-380 degrees C), (ii) the increase of the surface area and the larger nitrogen content with increasing pressure (100-200 bar), and (iii) the beneficial impact of the sodium content on the yield and the material crystallinity (Na/solvent ratio 1-2). (c) 2022 Elsevier Ltd. All rights reserved.

On the basis of the electromediated regeneration of beta-nicotinamide adenine dinucleotide hydrate (NADH) by chloro(2,2′-bipyridyl) (pentamethylcyclopentadienyl)-rhodium (III) chloride complex – Rh(III), the manuscript describes a modelling approach inspired by multiphase chemical engineering with gas absorption with chemical reaction. Here, the electrode surface is assimilated to the gas–liquid interface, and the reducing Rh(I) formed at the electrode corresponds to the dissolved gas. This method allows the kinetics of the liquid phase reaction between NAD+ and Rh(I) to be estimated and the beneficial effect of NAD+ concentration on the reduction current of Rh(III) to be successfully predicted. Moreover, because of the fast kinetics of the liquid phase reaction, the overall mediated regeneration of NADH by the redox Rh couple can be viewed as occurring as the direct reduction of NAD+ to NADH. The approach could be applied to other electromediated processes, upon sufficient knowledge of the system physico-chemical specificities.

The manuscript focuses on the use of pressure induced impedance spectroscopy (EPIS) to investigate transport phenomena in a membrane fuel cell in the presence of liquid water. A step-by-step approach is used to differentiate the different phenomena. Experiments were conducted in oxygen or air, at different currents, flowrates or relative humidities, with different GDLs (with or without MPL and PTFE) and in new or aged assemblies. In the presence of oxygen, over the whole frequency range (1-10 0 0 mHz), the greater the amount of liquid water, the higher the impedance modulus. This observation is accentuated with the absence of MPL, PTFE, and for an aged assembly. For frequencies below 10mHz, water transport is problematic, while gas transport appears impacted for frequencies above 100mHz. For a less efficient GDL with a large water excess, the phase shift is shifted toward negative values over 100mHz. In the presence of air, diffusion is superimposed on the previous phenomena: increase in the EPIS modulus at high frequencies and strong decrease in the phase shift. In the case of air and conditions close to flooding, the EPIS modulus increases severely in the range 0.1-1Hz and the phase shift increases strongly in positive values between 1-30 mHz.(c) 2022 Elsevier Ltd. All rights reserved.

The electrochemical regeneration of the reduced form of nicotinamide adenine dinucleotide cofactor (NADH) was realized in a hybrid flow reactor coupling fuel cell technology and redox flow device, paying attention to the robust immobilization of all catalysts. The rhodium catalyst Rh(Cp*)(bpy)Cl+ was covalently immobilized on a multi-walled carbon nanotube (MWCNT) layer and the association with the gas diffusion electrode was carefully optimized. High stability and activity of the electrochemical system were assessed by cyclic voltammetry and amperometry in the flow reactor. Afterwards, the optimal cofactor regeneration was applied to NADH-dependent biosynthesis using immobilized lactate dehydrogenase for the conversion of pyruvate to lactate in the flow cell in the presence of cofactor concentration as low as 10 mu M. 79 % Faradaic efficiency was achieved and remarkable total turnover number (TTN) were reached: 2500, 18000, and 180000, for NADH, Rh complex and L-lactate dehydrogenase (LDH), respectively.

The regeneration of the NADH cofactor is crucial for bioelectrocatalytic reactors. This can be achieved by using an electrochemical mediator such as the rhodium complex [Cp*Rh(bpy)Cl](+), but the overall reduction process suffers from the interference of molecular oxygen. This interference can be avoided by using a second porous working electrode (acting as a real oxygen filter) positioned near the surface of the first working electrode. To fabricate the oxygen filter, platinum particles were deposited on the surface of a carbon paper. NADH could be produced in the presence of the oxygen filter with a faradaic yield at 63.4 %, very close to the yields obtained without the filter at 61.7 % in a fully N-2-degased medium, and only at 10.6 % in the presence of oxygen. Moreover, the productivity was also increased by nearly a factor of four. Therefore, the proposed concept of the oxygen filter offers a new avenue in the current strategies for NADH regeneration in biocatalytic reactors based on electrochemical methods.

Electrochemical pressure impedance spectroscopy (EPIS) was introduced in view to differentiating transport/transfer phenomena of gas and liquid occurring in electrochemical cells. This work aimed at measuring EPIS impedance in a 100 cm(2) membrane fuel cell upon predominant control from gas transport, in conditions where the presence of liquid water is little significant. Operating the fuel cell with pure oxygen allowed observation of gas convection: EPIS impedance modulus was below 1 mu V Pa(-1 )in the frequency range 1 mHz-1 Hz, whereas the phase shift decrease did not exceed 30 degrees near 200 mHz with an MPL-free gas diffusion layer (GDL). Conversely, occurrence of diffusion phenomena with oxygen diluted into nitrogen or helium is revealed by the strong increase in the EPIS modulus up to 12-30 mu V Pa-1 near 500 mHz depending on the nature of the diluting gas, the GDL, and the excess in fed oxygen. Corresponding phase shift decreased regularly from nearly 0 degrees at 1 mHz to approx. -200 degrees at 1 Hz. The presence of liquid water and its poor management by the MPL-free GDL aggravates gas transport situation in the porous layers, in particular with more negative phase shifts and higher modulus at high frequency.

Beta-nicotinamide adenine dinucleotide (NAD(+)/NADH) is an important enzymatic co-factor that can be efficiently regenerated using a rhodium-based catalyst as electron transfer mediator (ie, [Cp*Rh(bpy)Cl](+), where Cp* = pentamethylcyclopentadienyl and bpy = 2,2-bipyridine). Here, the above mediated regeneration of NADH is implemented in a redox flow bioreactor hybridized with a gas diffusion electrode for hydrogen oxidation. The reactor was initially optimized with respect to rhodium complex and NAD(+) concentrations, humidification of the hydrogen gas, flow rates of both H-2 gas and electrolytic solution, and solution pH. The integration of an enzymatic reaction consuming the generated NADH was then investigated in a flow process, combining in series the electrochemical reactor to a biochemical cell with immobilized l-lactic dehydrogenase for the conversion of pyruvate to lactate. A high activity was achieved with a turnover number up to 370 h(-1) for NADH regeneration. Coupled electrochemical regeneration to enzymatic reaction led to total turnover number values of 2000 and 6.3 x 10(6) for NADH electrochemical regeneration and bioconversion, respectively.