Catalysts For Ethanol Oxidation Research Articles

Optimized Electrodeposition of Ni2O3 on Carbon Paper for Enhanced Electrocatalytic Oxidation of Ethanol.

The urgent need for sustainable and efficient energy conversion technologies has propelled research into novel electrocatalysts for fuel cell applications. This study investigates a carbon paper (CP)-supported Ni2O3 catalyst for the electrocatalytic oxidation of ethanol. We utilized electrodeposition to uniformly deposit/dop Ni2O3 onto the CP, creating an effective electrocatalyst. Our approach allows the tailoring of the doping degree by adjusting the electrodeposition potential. The optimal doping degree, achieved at a medium deposition potential, results in an electrode with high intrinsic activity and a substantial electrochemically active surface area (ECSA), thereby enhancing its electrocatalytic activity. This catalyst efficiently facilitates the oxidation of ethanol to formic acid while maintaining good stability. The enhanced performance is attributed to the effective interface and interaction between Ni2O3 and CP. This work not only provides insights into the design of efficient Ni-based catalysts for ethanol oxidation but also paves the way for developing advanced materials for renewable energy conversion.

Synthesis of Monodispersed Pd Nanoparticles and Ultrathin Twisty Pd Nanowire Networks for Electrooxidation of Ethanol.

In recent years, preparing precious metal catalysts with a controllable morphology has become a hot research topic for researchers. In this study, monodispersed palladium (Pd) nanoparticles (NP) and ultrathin Pd twisty nanowire networks (TNN) were synthesized in a solvothermal system using N,N-dimethylformamide (DMF) and oleylamine (OAm) as solvents, Transmission electron microscopy (TEM) images reveal the successful synthesis of nanoparticles and ultrathin TNN microstructures. Electrochemical data show that the current densities of Pd-NP and Pd-TNN for the ethanol oxidation reaction (EOR) reach 1878 mA mg-1 and 1765 mA mg-1, respectively. Compared to commercial Pd/C, Pd-TNN and Pd-NP exhibit better catalytic stability, lower electron transfer barriers, and more resistance to catalyst poisoning. Temperature, pH value, and ethanol concentration are all favorable for the EOR. According to the experimental data, the mechanism of enhanced electrocatalytic activity of Pd-NP and Pd-TNN catalysts for ethanol oxidation is discussed. This paper presents a method for preparing catalysts with stabilized structures to develop Pd-based catalysts for electrocatalytic oxidation reactions.

Designing Sustainable Ethanol Oxidation Catalysts: The Role of Graphene Oxide in NiCuGO Composite Material

The growing world population with the growth of civilization is causing the demand for electric energy to increase every year. For this reason, new energy sources such as fuel cells are becoming more and more needed, especially when they can use renewable fuel such as ethanol. This simple organic alcohol can be easily produced in a fermentation process using organic waste. Its oxidation might be used as a source for electricity; however, due to the lack of proper electrocatalytic materials, such a solution is not popular. A simple method of NiCuGO composite preparation via electrodeposition from a water-based solution containing graphene oxide suspension is proposed. The activity of the prepared material is proven, with higher current densities observed for the composite powder. The highest peak current density is observed for NiCuGO deposited with a higher current density. The observed ipA of 8.6 mA cm−2 has been higher than that reported by other researchers.

High-entropy PtCuSnWNb nanoalloys as efficient and stable catalysts for ethanol oxidation electrocatalysis.

Ternary nanoalloys used as electrochemical ethanol oxidation catalysts for direct ethanol fuel cells are confronted with poor stability issues under harsh acidic operating conditions. To address this issue, a carbon-supported quinary PtCuSnWNb high-entropy nanoalloy (denoted as PtCuSnWNb/C) was synthesized by using a polyol reduction method. Due to the unique high-entropy mixing states and strong catalyst-support interactions, PtCuSnWNb/C shows robust structural and compositional stability.

Pro‐catalytic Role of Transition Metal/Metal Oxide Blend Low Pd Catalysts for Ethanol Oxidation: Diminution of Activation Energy and Promoting Electrode Kinetics at Low Temperature

AbstractIn this investigation the effect of temperature on catalytic oxidation of ethanol on multi‐metallic PdCoNi/C nano‐composite bearing reduced palladium loading, have been studied over the temperature range 20 °C to 80 °C. The structure, composition and surface morphology of the catalyst regime were determined through the respective techniques like XRD, EDX and TEM while electro‐catalytic parameters were evaluated by the help of voltammetry, chronoamperometry, impedance spectroscopy and ion‐chromatography. The apparent activation energies (Ea) of ethanol oxidation reaction (EOR) were drastically reduced over PdCoNi/C compared to Pd/C reflecting the energy efficiency of ternary matrix furnished with only 35 % Pd loading and the rest 65 % being cheaper transition metals. The long term poisoning rates warrant improved stability of PdCoNi/C and also figure out the robustness of the catalyst even at 20 °C. The Ea value is remarkably reduced, rendering appreciable mass activity in terms of current density per mg of Pd at each of the temperatures studied. The incorporation of transition metals Co and Ni onto Pd becomes particularly effective in orienting the EOR proceed through carbonate pathway as reflected by the columbic efficiency in terms of oxidation product yield ~5 times higher, compared to single Pd catalyst throughout the temperature range.

Pd/PdO doped WO3 with enhanced selectivity and sensitivity for ppb level acetone and ethanol detection

Ethanol and acetone sensors have a wide variety of applications across different industries. However, it is necessary to improve the performance of such sensors and to understand the underlying mechanisms. In this study, Pd/PdO-WO3 nanoblocks are synthesized via hydrothermal growth and calcination. The Pd and PdO contents of the materials are tuned by varying the Pd doping concentration and annealing temperature. The gas sensing performance of the nanoparticles is investigated, which shows that Pd doping increases the sensitivity and reduces the optimum operating temperature. At 200 °C, Pd/PdO-WO3 nanoblocks with different PdO ratios exhibit good sensitivity to acetone and ethanol. However, because PdO is an active catalyst for ethanol oxidation, the oxygen sensitivity increases as the PdO ratio increases. The prepared sensors exhibit good stability and excellent selectivity against a variety of interferents, and the detection limit of the target gas is 100 ppb. The chemical and electronic sensitization of Pd/PdO lowers the activation barrier and improves the gas sensing response. This study demonstrates that the selectivity of a gas sensor can be regulated by controlling the electronic states of the active species.

Catalytic activity and stability of ethanol oxidation catalysts based on transition metals and transition metal spinels in alkaline ethanol media

Catalytic activity and stability of ethanol oxidation catalysts based on transition metals and transition metal spinels in alkaline ethanol media

In situ Raman study of high potential scan enhanced Pt/C and Pd/C catalyst performance for ethanol oxidation

The efficient catalysis of ethanol oxidation (EOR) is of paramount importance for the progress of energy conversion and storage technologies. We investigate the improved catalytic performance of commercial J-M Pt/C and Pd/C catalysts for ethanol oxidation by utilizing high potential scanning. By employing in situ Raman spectroscopy, we analyze the reaction intermediates during electrochemical reactions. Our findings highlight that the Pd/C catalyst exhibits remarkable enhancements in catalytic activity and stability, which can be attributed to the activation at high potentials on Pd/C electrode. Interestingly, different results are observed between Pt/C and Pd/C catalysts under the same experimental conditions. This study provides valuable insights into the design and development of efficient catalysts for ethanol oxidation.

(100) Preferentially Exposed Pt–Sn Nanosheets with Enhanced C–C Bond Scission as a High-Performance Catalyst for Ethanol Oxidation

Ethanol is a kind of green and sustainable liquid fuel with high energy density, which has a promising application prospect in liquid fuel cells. Improving the anti-poisoning ability and C–C bond cleavage ability of Pt-based catalysts is critical for achieving efficient ethanol oxidation reaction. Here, Pt–Sn nanosheets preferentially exposed with metastable (100) facets rather than thermodynamically stable (111) facets were synthesized through a simple hydrothermal method. Our experiment results demonstrated that the as-synthesized (100) faceted Pt–Sn nanosheets exhibited a good electrocatalytic performance, i.e., higher CO2 selectivity and better stability when compared with Pt–Sn nanoparticles with irregular morphology and commercial Pt/C. The electrochemical in situ infrared spectroscopy tests revealed that the Pt–Sn nanosheets alleviate the binding strength of reaction intermediates and further promote the electrooxidation of intermediates, thereby displaying a good CO2 selectivity at a lower potential and over a wide range of potentials. This work demonstrates the important roles of the facet effect and alloying effect in electrocatalytic properties of noble metal catalysts.

PdPtBi networked nanowires derived from Pd nanosheets as efficient catalysts for ethanol oxidation

PdPtBi networked nanowires derived from Pd nanosheets as efficient catalysts for ethanol oxidation

Reduced graphene oxide as efficient carbon support for Pd-based ethanol oxidation catalysts in alkaline media

The sluggish kinetics of the ethanol oxidation reaction (EOR) and the related development of low-cost, highly active and stable anode catalysts still remains the major challenge in alkaline direct ethanol fuel cells (ADEFCs). In this respect, we synthesized a PdNiBi nanocatalyst on reduced graphene oxide (rGO) via a facile synthesis method. The prepared composite catalyst was physicochemically characterized by SEM, STEM, EDX, ICP-OES and XRD to analyze the morphology, particle distribution and size, elemental composition and structure. The electrochemical activity and stability towards EOR in alkaline media were examined using the thin-film rotating disk electrode technique. The results reveal well-dispersed and strongly anchored nanoparticles on the rGO support, providing abundant active sites. The PdNiBi/rGO presents a higher EOR activity and stability compared to a commercial Pd/C ascribed to a high ECSA and synergistic effects between Pd, Ni and Bi and the rGO material. These findings suggest PdNiBi/rGO as a promising anode catalyst in ADEFC applications.

Synergistic Effect in Ag/Fe–MnO2 Catalysts for Ethanol Oxidation

Here we report the synergistic effect of OMS-2 catalysts tested in ethanol oxidation, and the effects produced by both the addition of an Fe modifier in the catalyst preparation stage, and the introduction of Ag on its surface by the impregnation method. To analyze the action of each component, the Fe-modified, Ag-containing OMS-2 catalysts with different Mn/Fe ratios were prepared. Combined XPS and XRF elemental analysis confirms the states and distribution of the Ag- and Fe-containing species between the surface and bulk of the OMS-2 catalysts, which form highly dispersed Ag species on the surface of 0.05Fe–OMS-2, and are also incorporated into the OMS-2 crystalline lattice. The cooperative action of Ag and Fe modifiers improves both reoxidation ability (TPO results) and the amount of adsorbed oxygen species on the catalyst surface. The introduction of Ag to the OMS-2 and 0.05 Fe–OMS-2 surface allows a high level of activity (T80 = 150–155 °C) and selectivity (SAc80 = 93%) towards the acetaldehyde formation.

Platinum nanoparticles deposited on Cu-doped NiO/C hybrid supports as high-performance catalysts for ethanol and glycerol electrooxidation in alkaline medium

In this work, the influence of Cu-doping on the ability of NiO co-catalyst to enhance the electrocatalytic properties of carbon-supported Pt nanoparticles toward ethanol and glycerol oxidation was investigated. The Cu-doped NiO particles were synthesized by a precipitation method, while the noble metal nanoparticles were deposited over the hybrid Cu-doped NiO/C supports via a pulsed microwave-assisted polyol method using ethylene glycol as reductant. Pt-NiO and Pt-NiOCuO(x:y)/C catalysts with Ni:Cu atomic ratios of 9:1 (Pt-NiOCuO(9:1)/C), 7:3 (Pt-NiOCuO(7:3)/C) and 5:5 (Pt-NiOCuO(5:5)/C) were obtained. The physicochemical analysis showed that the as-prepared catalysts are composed of nanoparticles of about 3 nm. The potentiostatic experiments exhibited that the Pt-NiOCuO(7:3)/C catalyst is the most active catalyst for ethanol oxidation, while the Pt-NiOCuO(5:5)/C catalyst exhibited the best performance for glycerol oxidation. These catalysts developed mass current densities of almost 12 and 5 times higher than those of bare Pt/C for ethanol and glycerol oxidation reactions, respectively. Moreover, an accelerated multicycling stability test displayed that the as-prepared catalysts retain almost 98% of their initial mass current density.

Designing New Material Based on Functionalized Multi-Walled Carbon Nanotubes and Cu(OH)2-Cu2O/Polypyrrole Catalyst for Ethanol Oxidation in Alkaline Medium.

In this work, copper(II) hydroxide (Cu(OH)2) and copper oxide (Cu2O) nanostructures are deposited on functionalized multi-walled carbon nanotubes/polypyrrole to report an efficient electrocatalyst for ethanol oxidation in alkaline medium. In the first step, the deposition of functionalized multi-walled nanotubes of carbon (F-MWCNTs) on the electrode surface was carried out using drop casting mode followed by the electrodeposition of polypyrrole (PPy) and copper nanoparticles (Cu-Nps) using galvanostatic mode. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed in order to study the morphology and the structure of the elaborated catalysts. Electrochemical characterization conducted by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) revealed that the introduction of functionalized multi-walled carbon nanotubes enhances the electric properties of the nanocomposites and offers a large active surface area. The prepared electrocatalyst was then tested in a solution of 0.1 M NaOH containing 0.2 M of ethanol showing high performance (7 mA cm−2 at 0.85 V vs Ag/AgCl) and good stability (over 1800 s) toward ethanol oxidation.

Modification of commercial Pt/C catalyst by cobalt for enhanced electro-oxidation of ethanol

An easy and efficient method was considered to enhance the activity of Pt/C catalyst for ethanol oxidation by formation of a platinum-cobalt alloy via electrodeposition technique. The morphology and structural properties of the prepared Pt-Co/C alloy catalyst were determined by SEM, EDX and XRD. The XRD curves confirmed Pt characteristic peaks at around 2θ = 39.76° (111) and 46.23° (200) while the existence of Co was not clear at 2θ = 44.5° and 51.85° owing to its alloying with Pt. CV, CA, EIS techniques were employed to examine the electrochemical behavior of the Pt-Co/C catalyst. The impedance data were fitted to the Randles circuit to obtain the parameters for a single faradic reaction coupled with mass transfer. The Pt-Co/C catalyst showed better performance in terms of the onset potential and current density. The sample containing Pt-Co/C catalyst exhibited about 2 times more current density than the commercial Pt/C catalyst.

Carbon Dots Promote the Performance of Anodized Nickel Passivation Film on Ethanol Oxidation by Enhancing Oxidation of the Intermediate†

Main observation and conclusionEthanol is considered a better fuel than methanol in direct alcohol fuel cells because of the high energy density and low toxicity. Compared with noble metal catalysts, nickel‐based catalysts are much cheaper in price. However, present nickel‐based catalysts still surfer from some disadvantages such as low activity and high overpotential. In this paper, we show a new and high efficient nickel‐ based catalyst for ethanol oxidation. A layer of anodized nickel passivation film (Ni‐APF) was formed on the surface of nickel sheet by anodic oxidation method with carbon dots (CDs) as co‐catalyst. At the current density of 110 mA·cm−2, the potential for Ni‐APF/CDs was only 0.541 V (vs. Ag/AgCl), which was 18.8% lower than that of Ni‐APF. Low overpotential could reduce electrode thermal loss and increase output energy. Ni‐APF/CDs showed 144.4 mA∙cm−2 peak current density at peak potential 0.662 V (vs. Ag/AgCl), which was 31% higher than that of Ni‐APF (110.3 mA∙cm−2). In this system, CDs mainly function in the increase of charge‐transfer capacity and the promotion oxidation of carbonaceous intermediates.

Effect of electrochemical activation on the performance and stability of hybrid (PPy/Cu2O nanodendrites) for efficient ethanol oxidation in alkaline medium

Abstract One of the most challenges in Direct Ethanol Fuel Cell (DEFC) is to prevent the poisoning of the surface of the electrode due to the slow kinetics of ethanol oxidation reaction. Herein, we report the development of a new catalysts for ethanol oxidation using a well-defined Cu2O nanodendrites (Cu2O-NDs) supported on polypyrrole film (PPy) using a simple electrochemical approach. The effect of regeneration of the electrocatalyst in acidic medium on the performance of ethanol electro-oxidation was reported for the first time. Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were used to characterize the new catalysts. The SEM and TEM images confirm that the octahedral shape of Copper oxide is converted to a dendritic one after the regeneration of the catalyst. The electrochemical behavior of the prepared catalysts towards the oxidation of ethanol were investigated by Cyclic voltammetry (CV), Chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The current obtained by CV measurements on Cu2O-NDs/PPy/CPE was about 4 mA cm−2 which is 1.77 time higher than Cu2O/PPy/CPE catalyst (2.25 mA cm−2) with a shift of 60 mV and 150 mV in anodic and onset potential respectively demonstrating a good catalytic performance for ethanol oxidation. The stability test shows that the Cu2O-NDs/PPy/CPE loses only 7.25% of its initial current after 1000 cycles. Finally, Ex–situ FTIR spectroscopy was conducted in order to understand the reaction mechanism. Interestingly, our ex-situ FTIR results demonstrated that the ethanol oxidation mechanism displayed shape dependent behavior of copper oxide, indicating that the ethanol molecules are totally oxidized on the Cu2O-NDs leading to the formation of CO2 molecule as final product.

Synergistic catalytic activity of palladium–silver alloy nanoparticle for anodic oxidation of ethanol in alkali

Palladium and palladium-silver alloy nano catalysts were synthesized from aqueous precursor at room temperature via a single vessel chemical reduction and co-reduction methods in absence of capping agent. XPS analysis confirms the presence of Pd and Ag in the catalyst matrix. Microscopic analyses reveal spherical morphology of the catalyst in the nanoscale dimension. The electro-analytical investigation of the catalyst loaded on carbon electrode shows that the Pd4Ag nano alloy catalyst demonstrates marked improvement in electro-catalytic efficiency among all prepared catalysts for ethanol oxidation in alkali. The Pd4Ag/C catalyst shows the mass normalized peak current density of 522 mA mg−1Pd in cyclic voltammetric (CV) study, which is 1.97 times greater than that of similarly synthesized Pd/C (264.2 mA mg−1Pd) catalyst. Chronoamperometric and impedance analyses further establish the superiority of Pd4Ag/C catalyst. To discover the plausible mechanism, the CV study is typically extended to the intermediates like sodium acetate which reveals that though Pd is better for catalytic oxidation of intermediate than the best catalyst but the optimal OH− adsorption on the surface of the metal, favours catalytic oxidation of ethanol more on Pd4Ag catalyst. The mechanistic path of the reaction is anticipated by evaluating the ex-situ FTIR and chromatographic studies which explain the promotion of the formation of carboxylate in comparison to carbonate by Ag.

Modification of Carbon Black by Thermal Decomposition of Lead Acetylacetonate to Improve Activities for Ethanol Oxidation at Supported Pt Catalysts

Thermal decomposition of lead acetylacetonate was used to modify high surface area carbon black supports for ethanol oxidation catalysts. X-ray diffraction showed that the main product was Pb3(CO3)2(OH)2 (basic lead carbonate). Platinum nanoparticles were prepared separately and adsorbed onto the modified supports, and electrodes were fabricated by painting catalyst inks onto carbon fibre paper. The presence of Pb3(CO3)2(OH)2 greatly enhanced the activity of the Pt nanoparticles for ethanol oxidation, particularly in cyclic voltammetry. However, a rapid decay of the enhancement was observed in chronoamperometry at low potentials, suggestion that there were changes in the nature of the Pb containing layer with time and potential in the aqueous sulfuric acid electrolyte.

Synthesis and testing of cobalt leaf-like nanomaterials as an active catalyst for ethanol oxidation

A simple electrodeposition technique has been used to synthesize Co nanoparticles with a 3D leaf-like morphology at room temperature. The prepared Co material has a layered sheet structure of a few nanometers thickness. The surface area of the Co leaf-like structure is three times higher than that of the Co nanoparticles. The prepared nanoparticles exhibit high activity towards ethanol oxidation in alkaline media with an onset potential of 0 V vs Ag/AgCl, which is one of the lowest reported potentials for a non-precious catalyst. The current density is observed to increase with increasing ethanol concentration from 0.1 M to 2 M, after which it plateaus. Mixing the Co catalyst with Vulcan carbon (20 wt%) resulted in a 50% increase in current discharge at different ethanol concentrations due to the improvement in mass and charge transfer rates as confirmed by EIS measurements. Also, Co deposited in situ on the surface of nickel foam (NF) exhibited a high activity towards ethanol oxidation as a standalone electrode that is 10 times that of bare NF.