• Energy Research

Glycerol Electrooxidation Reaction (GEOR) has been herein investigated on Rh/C and Rh/SnO2-C prepared by polyol method. The particle mean sizes were found to be 2.0 and 1.8 nm in Rh/C and Rh/SnO2-C, respectively. The alloying degree reached 63% in Rh/SnO2-C, confirming a Sn-Rh alloy formation. The activity towards GEOR on Rh/SnO2-C was almost 5-fold higher than on Rh/C, as demonstrated by electrochemical measurements in alkaline medium. This trend indicated the beneficial effect of the SnO2-C carbon-oxide composite support in the catalyst composition. Analysis of the products generated after the bulk electrolysis using high-performance liquid chromatography (HPLC) and FTIRS demonstrated that at 0.55 V vs RHE the main reaction products were glycerate ion and carbonate (CO3 2−). Then, a C–C–C cleavage was demonstrated with the CO3 2− formation at low potentials. During the testings conducted in a home-made acrylic direct glycerol fuel cell at room temperature in 0.5 mol l−1 NaOH, the maximum power density (390 μW cm−2) obtained on a Rh/SnO2 anode, was 5-fold higher than that on Pd/C. These testings demonstrated that the co-generation of sustainable energy and value-added products is a promising way to valorize glycerol.

An electrocatalyst with Cu nanoparticles embedded in a mesoporous carbon was prepared by the soft-template route using a green process. Its particular structure boosts its performance for CO2RR regarding selectivity and charge/mass transfers.

Abstract Mathematical modeling has been extensively applied to the study and development of fuel cells. In this work, the objective is to characterize a mechanistic model for the anode of a direct ethanol fuel cell and perform appropriate simulations. The software Comsol Multiphysics ® (and the Chemical Engineering Module) was used in this work. The software Comsol Multiphysics ® is an interactive environment for modeling scientific and engineering applications using partial differential equations (PDEs). Based on the finite element method, it provides speed and accuracy for several applications. The mechanistic model developed here can supply details of the physical system, such as the concentration profiles of the components within the anode and the coverage of the adsorbed species on the electrode surface. Also, the anode overpotential–current relationship can be obtained. To validate the anode model presented in this paper, experimental data obtained with a single fuel cell operating with an ethanol solution at the anode were used.

AbstractThe ethylene glycol oxidation reaction on nickel and ruthenium modified palladium nanocatalysts was investigated with electrochemical, spectroelectrochemical, and chromatographic methods. These carbon‐supported materials, prepared by a revisited polyol approach, exhibited high activity towards the ethylene glycol electrooxidation in alkaline medium. Electrolysis coupled with high performance liquid chromatography/mass spectrometry (HPLC‐MS) and in situ Fourier transform infrared spectroscopy (FTIRS) measurements allowed us to determine the different compounds electrogenerated in the oxidative conversion of this two‐carbon molecule. High value‐added products such as oxalate, glyoxylate, and glycolate were identified in all electrolytic solutions, whereas glyoxylate was selectively formed at the Ru45@Pd55/C electrode surface. In situ FTIRS results also showed a decrease in the pH value in the thin layer near the electrode as a consequence of OH− consumption during the spectroelectrochemical experiments.

Abstract Cellulosic biomass, which is basically a polymer of glucose, is the most abundant organic polymer on earth and there is significant interest in the development of advanced materials for its valorization through the waste-to-energy and water-to-chemical scenarios. Hence, a precise investigation of the monomer (glucose) electrooxidation in electrochemical reactors is a key starting point to tackle the whole cellulose and ultimately the entire biomass. To this end, we report herein new insights about the operation of a cogeneration direct alkaline glucose fuel cell (which includes an anion exchange membrane) that simultaneously produces electricity and mainly gluconate as the reaction product. The AuPt nanocatalysts of 3–5 nm particle size finely dispersed onto reduced graphene oxide (rGO) at a 20 wt% metal loading are obtained from an organic surfactant-free method, so-called the bromide anion exchange (BAE). Specifically, the electroanalytical investigation carried out with high-performance liquid ionic chromatography (HPLIC) and liquid chromatography coupled to mass spectrometry (LC-MS) demonstrate no carbon–carbon bond cleavage occurs, which represents an advance towards a CO2-free biomass valorization process. The comparison of the results commonly obtained in a three-electrode half-cell with those in an anion exchange membrane fuel cell shows that the trends in selectivity are the same. The fuel cell operation produces gluconate via a two-electron transfer process at 90% selectivity and 65% Faradaic efficiency. In addition to gluconate, glucuronate is also observed; both compounds are high value-added chemicals. This work contributes towards the engineering of novel electrocatalytic interfaces for the valorization of the surplus biomass into energy and chemicals.

AbstractWe report a straightforward design for a hybrid glucose biofuel cell (h‐GBFC) operating at pH 7.4 with 10 mM glucose at 37 °C. Homemade electrospun carbon nanofibers were used as electrode support. Clean and highly active gold‐based nanomaterials (3–6 nm) were synthesized for glucose electrooxidation. Enhanced catalytic activity toward glucose oxidation has been highlighted. Bilirubin oxidase enzyme was used to catalyze the oxygen reduction reaction. The constructed h‐GBFCs exhibit an unexpected and highly improved open circuit voltage of 0.92 V, which is the best value so far reported for such cells. The abiotic Au60Pt20Pd20/C anode induces high electrical performance with a maximum power density of 91 µW cm−2 at 0.365 V. This improvement over monometallic anode catalysts has been assigned to synergistic effects between gold, platinum, and palladium. Strategies developed herein will serve as guidelines for the development of new rational pathways to more powerful, stable, and promising GBFC designs.

The oxygen reduction reaction (ORR) is the oldest studied and most challenging of the electrochemical reactions. Due to its sluggish kinetics, ORR became the major contemporary technological hurdle for electrochemists, as it hampers the commercialization of fuel cell (FC) technologies. Downsizing the metal particles to nanoscale introduces unexpected fundamental modifications compared to the corresponding bulk state. To address these fundamental issues, various synthetic routes have been developed in order to provide more versatile carbon-supported low platinum catalysts. Consequently, the approach of using nanocatalysts may overcome the drawbacks encountered in massive materials for energy conversion. This review paper aims at summarizing the recent important advances in carbon-supported metal nanoparticles preparation from colloidal methods (microemulsion, polyol, impregnation, Bromide Anion Exchange…) as cathode material in low temperature FCs. Special attention is devoted to the correlation of the structure of the nanoparticles and their catalytic properties. The influence of the synthesis method on the electrochemical properties of the resulting catalysts is also discussed. Emphasis on analyzing data from theoretical models to address the intrinsic and specific electrocatalytic properties, depending on the synthetic method, is incorporated throughout. The synthesis process-nanomaterials structure-catalytic activity relationships highlighted herein, provide ample new rational, convenient and straightforward strategies and guidelines toward more effective nanomaterials design for energy conversion.