Performance For Electrooxidation Research Articles

Interface Enables Faster Surface Reconstruction in a Heterostructured CuSey/NiSex Electrocatalyst for Realizing Urea Oxidation.

Creating affordable electrocatalysts and understanding the real-time catalytic process of the urea oxidation reaction (UOR) are crucial for advancing urea-based technologies. Herein, a Cu-Ni based selenide electrocatalyst (CuSey/NiSex/NF) was created using a hydrothermal technique and selenization treatment, featuring a heterogeneous interface rich in Cu2-xSe, Cu3Se2, Ni3Se4, and NiSe2. This catalyst demonstrated outstanding urea electrooxidation performance, achieving 10 mA cm-2 with just 1.31 V and sustaining stability for 96 h. Through in-situ Raman spectroscopy and ex-situ characterizations, it is discovered that NiOOH is formed through surface reconstruction in the UOR process, with high-valence Ni serving as the key site for effective urea oxidation. Moreover, the electrochemical analysis revealed that CuSey had dual effects. An analysis of XPS and electrochemical tests revealed that electron transfer from CuSey to NiSex within the CuSey/NiSex/NF heterostructure enhanced the UOR kinetics of the catalyst. Additionally, according to the in-situ Raman spectroscopy findings, the existence of CuSey facilitates a easier and faster surface reconstruction of NiSex, leading to the creation of additional active sites for urea oxidation. More significantly, this work provides an excellent "precatalyst" for highly efficient UOR, along with an in-depth understanding of the mechanism behind the structural changes in electrocatalysts and the discovery of their true active sites.

Hydrazine electrooxidation performance of cyano-substituted indole derivatives as organic anode catalyst

Here we present the new EWG-substituted indole derivatives, namely 2-((5-(1-methyl-2-phenyl-1 H-indol-3-yl)thiophen-2-yl)methylene) malonitrile (IPTM), 2-((5-(1-methyl-2-phenyl-1 H-indol-3-yl)furan-2yl)methyl)malonitrile(IPFM) and 2-((4-(1-methyl-2-phenyl-1 H-indol-3-yl)benzylidene) malonitrile (IPPM) was synthesized by using Sonogashira coupling, electrophilic cyclization, Suzuki-Miyaura coupling and condensation reactions. The isolated yields were obtained as 86 %, 71 %, and 69 % yields, respectively. Cyclic voltammetry(CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) were used for the electrochemical measurements to observe the electrocatalytic behavior of IPTM, IPFM and IPPM. The results exhibited that the highest-performance organic-based catalyst was 2.601 mA/cm2 (0.073 mA/mg) for IPPM which could be a good candidate as a metal-free electrocatalyst for hydrazine electrooxidation.

RhCuBi Trimetallenes with Composition Segregation Coupled Crystalline‐Amorphous Heterostructure Toward Ethanol Electrooxidation

AbstractThe inefficiency of Pt and Pd benchmark catalysts in achieving complete ethanol oxidation, coupled with their inherent susceptibility to poisoning, poses a significant obstacle to the advancement of direct ethanol fuel cells. In this study, the development of self‐supported and ultrathin RhCuBi trimetallenes, demonstrating exceptional performance in ethanol electrooxidation through segregation and interface engineering is presented. The distinctive RhBi‐rich crystalline/RhCu‐rich amorphous heterostructure of RhCuBi trimetallenes creates a wealth of highly active interfacial sites for the ethanol oxidation reaction (EOR). This results in an impressive 43.3% Faradaic efficiency for the C1 pathway and a peak mass activity of 1.11 A mgRh−1 at 0.68 V versus reversible hydrogen electrode. Moreover, RhCuBi trimetallenes retain 60% of their initial mass activity after 8.5 h of constant potential electrolysis, outperforming commercial Pd and Pt catalysts (<3%). In/ex situ infrared spectroscopy directly reveals the generated C1 products and the key CH3CO* intermediates for EOR on RhCuBi trimetallenes. Theoretical calculations confirm that the RhBi alloy, particularly the lattice‐stretched crystalline/amorphous interfacial sites, facilitates the adsorption/activation of ethanol and the dehydrogenation of CH3CO* toward the C1 pathway of EOR. This breakthrough offers promising prospects for enhancing the efficiency and stability of ethanol electrooxidation in fuel cell applications.

Self-Assembly Dual Active Site Nanocomposite Anode Ce0.6Mn0.3Fe0.1O2-δ/NiFe/MnOx for Electrooxidative Dehydrogenation of Ethane to Ethylene.

As the demand for ethylene grows continuously in industry, conversion of ethane to ethylene has become more and more important; however, it still faces fundamental challenges of low ethane conversion, low ethylene selectivity, overoxidation, and instability of catalysts. Electrooxidative dehydrogenation of ethane (EODHE) in a solid oxide electrolysis cell (SOEC) is an alternative process. Here, a multiphase oxide Ce0.6Mn0.3Fe0.1O2-δ-NiFe-MnOx has been fabricated by a self-assembly process and utilized as the SOEC anode material for EODHE. The highest ethane conversions reached 52.23% with 94.11% ethylene selectivity at the anode side and CO with 10.9 mL min-1 cm-2 at the cathode side, at 1.8 V at 700 °C. The remarkable electrooxidative performance of CMF-NiFe-MnOx is ascribed to the NiFe alloy and MnOx nanoparticles and improvement of the concentration of oxygen vacancies within the fluorite substrate, generating dual active sites for C2H6 adsorption, dehydrogenation, and selective transformation of hydrogen without overoxidizing the ethylene generated. Such a tailored strategy achieves no significant degradation observed after 120 h of operation and constitutes a promising basis for EODHE.

Catalytic insights into methanol electrooxidation on Ni foam modified with Bi2O3 - Acetylene black-rGO: Synthesis, characterization, and performance evaluation

The aim of this study was to develop efficient anode materials for direct methanol fuel cell applications. The Ni foam was modified with Bi2O3 - acetylene black-rGO to increase catalytic activity toward methanol oxidation. The Bi2O3 was synthesized via a straightforward green technique. The characterization was achieved by using Fourier transform infrared spectroscopy and X-Ray diffraction analysis. The transmission electron microscope and field emission scanning electron microscope was utilized to evaluate the surface properties of catalysts, and energy-dispersive X-ray spectroscopy were employed to determine the chemical composition. Bi2O3 particles with diameters ranging from 15 to 75 nm were crystal structures in the (111), (220), (311), and (342) crystal planes. The performance of methanol electrooxidation in an alkaline medium was investigated using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry techniques. The surface coverage of the redox species was 2.04 × 10−5 mol g−1, and the diffusion coefficient ranged between 8.02 × 10−12 and 1.25 × 10−13 cm2 s−1. According to the obtained results, the Bi2O3 - acetylene black-rGO modification enhanced the electrocatalytic activity of Ni foam against methanol oxidation in an alkaline medium.

Investigation of the performance of (4-(3-iodobenzo[b]thiophen-2-yl)-N,N-dimethyllaniline as an anode catalyst for glucose electrooxidation

In this study (4-(3-iodobenzo[b]thiophen-2-yl)-N,N-dimethyllaniline (4), Sonagashira Coupling Reaction was synthesized using Electrophilic Cyclization Reactions. Then, the anode catalyst performance for glucose electrooxidation was investigated. The electrocatalytic activities of the organic catalyst were investigated by CV, CA and EIS measurements in 1 M KOH + 0.5 M C6H12O6 solution. Interestingly, electrochemical depositing on organic catalyst by Pd metal increased the specific activity, and it was calculated as 0.61 mA/cm2 Consequently, Pd@4 catalyst will be used as an electrocatalyst with high specific and stability and low charge transfer activity.

Polysaccharides derived from Ganoderma lucidum applied to the extraction chitosan and development of electrochemical sensor based on extracted chitosan and graphitic carbon nitride modified electrode for determination nitrite in food samples

The current study focused on extracting chitosan from polysaccharides generated from Ganoderma lucidum and applying it to the construction of electrochemically modified electrodes based on graphitic carbon nitride (g-C3N4) for the measurement of nitrite in water and food samples. Ganoderma Lucidum polysaccharides were isolated and characterized. The chitosan was then isolated enzymatically from the polysaccharides using a chemical technique. The isolated chitosan and g-C3N4 were used to modify a GCE (chitosan/g-C3N4/GCE). The structural investigations employing FT-IR, SEM, and XRD show that chitosan successfully interacted with g-C3N4 in the chitosan/g-C3N4 sample. Electrochemical evaluation using cycle voltammetry (CV), differential pulse voltammetry (DPV), and amperometry revealed that the chitosan/g-C3N4/GCE electrode has good sensitivity and selectivity for determining nitrite. The use of chitosan and g-C3N4 in electrode surface modification improved nitrite electro-oxidation performance by allowing for more effective adsorption and electron transport processes. DPV measurement showed that the sensor had a sensitivity of 0.12103 μA/μM, a linear range of 40 to 2000 μM, and a limit of detection of 21 nM, and amperometry measurement showed the sensor's sensitivity of 0.15487 μA/μM, linear range of 20 to 4230 μM, and an LOD of 10 nM. These findings indicated a more sensitive and wide range of sensor performance using amperometry with respect to the DPV technique. The method's validity and accuracy in determining nitrite in prepared genuine samples (water, milk, apple juice, orange juice, Aloe vera, and tomato juice) were investigated. RSD values (3.19 % to 4.75 %) and recovery values (80.00 % to 98.33 %) were found to be satisfactory. The data also revealed that there were no substantial matrix interferences, demonstrating the accuracy and applicability of the proposed approach for detecting nitrite in food samples. Therefore, the proposed sensor design has several advantages that make it a promising candidate for various applications. Its reusability, stability, wide linear range, accuracy, and low cost make it an attractive option for many industries.

Kraft Lignin Electro-Oxidation under Ambient Temperature and Pressure

Lignin is the largest natural source of aromatic chemicals. Due to its complex polymeric structure, Kraft lignin is under-utilized and usually combusted for heat generation, thus resulting in CO2 emissions in the Kraft process. To valorize lignin with renewable electricity and to convert it into value-added aromatic chemicals, efficient electrochemical methods need to be discovered, based not only on its apparent yield of building block chemicals but also on its energy efficiency. In this study, the electro-oxidative performance of six different metals was systematically evaluated. The results showed that the synthesized Ni-based catalyst can increase the vanillin and vanillic acid apparent yield by 50–60% compared to when Ni-based catalyst is absent. We also found that the oxygen evolution reaction (OER) is more than a competing reaction since the presence of oxygen synergistically aids oxidation of the lignin to increase aromatic chemical production by 63% compared to the sum of vanillin generation from both voltage-only and oxygen-only scenarios. With the novel proposed notion of charge efficiency, we showed that utilizing a thinner layer of Ni catalyst balances the OER and the oxidative reaction of lignin, thus improving the charge efficiency for vanillin by 22%

Palladium chalcogenide nanosheets with p-d orbital hybridization for enhanced alcohol electro-oxidation performance

Ethanol oxidation reaction (EOR) is an important energy conversion process. Herein, we have proposed palladium chalcogenide nanosheets to improve C-C bond cleavage ability for EOR. The mass activity of the Te-Pd nanosheets (NSs)/C, which is higher than Se-Pd NSs/C and S-Pd NSs/C (6.9 A mg−1 and 5.3 A mg−1), has achieved 10.0 A mg−1, 12.5-fold higher than commercial Pd/C (0.8 A mg−1) and 8.3 times higher than Pd NSs/C (1.2 A mg−1). The Faradaic efficiency of C1 pathway for EOR on the Te-Pd NSs/C can improve to 56.6% compared with Pd NSs/C (25.7%) at 0.8 VRHE. Density functional theory calculations reveal that the orbital hybridization between Pd and Te weakens the adsorption energy of intermediates and reduces the energy barrier of the rate-determining steps in the C1 pathway. Besides, these palladium chalcogenide NSs can also serve as efficient electrocatalysts for ethylene glycol oxidation reaction and methanol oxidation reaction.

Oxygen vacancies modulated Co3O4 toward highly efficient electrooxidation of 5-hydroxymethylfurfural

Electrochemical oxidation of 5-hydroxymethylfurfural (HMF) has emerged as a promising method to produce highly valuable chemicals. Co-based electrocatalysts with oxygen vacancies are one of the most promising candidates. However, the relationship between their electrocatalytic behavior and the vacancy concentration is still ambiguous. In this work, the diverse oxygen vacancy contents of Co3O4 were realized via a simple adsorption-pyrolysis method and confirmed by X-ray diffraction, Raman, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy, respectively. It was found that the Co3O4 with proper oxygen vacancies prepared at optimized conditions exhibits a superior catalytic activity for HMF oxidation reaction (HMFOR) in 1.0 M KOH with 50 mM HMF electrolyte (with the potential of 1.35 V vs. RHE at 10 mA cm−2). Correlational characterizations and density functional theory calculations demonstrate that appropriate oxygen vacancies can promote HMF electrooxidation performance, whereas excessive oxygen vacancies can hinder electron transport and result in a significant decline in HMF electrooxidation performance. This study reveals the significance of appropriate oxygen vacancies in catalytic oxidation activity and provides important insights into the role of oxygen vacancies in catalytic oxidation reactions for the synthesis of defective material.

Facile Synthesis of the TiO2-Supported Ultrathin Palladium Facet Composite Catalyst with Superior Metal Dispersion and Enhanced Catalytic Performance in Formic Acid Electro-Oxidation

Facile Synthesis of the TiO₂-Supported Ultrathin Palladium Facet Composite Catalyst with Superior Metal Dispersion and Enhanced Catalytic Performance in Formic Acid Electro-Oxidation

Universal interface-confined strategy for trough-like AgPtM (M=Ru, Ir, Sn) nanostructures for methanol electro-oxidation

AgPt-based tri-metallic electrocatalyst as an emerging electrocatalyst is demonstrated to have superior catalytic performance. However, it still lacks a universal synthesis strategy currently because of the participation of multiple precursors with different electrical reduction potentials, which is greatly limited to developing high-performance electrocatalysts. Here, a universal interface-confined strategy method is developed to transform the starting Ag nanowires into a series of novel AgPtM (M=Ru, Ir, Sn) alloy nanotroughs at water/air interface. Moreover, owing to their unique trough-like structure, rough surface and the electronic synergistic effect between oxyphilic metals and Pt component, the AgPtM (M=Ru, Ir, Sn) alloy nanotroughs all show enhanced electrocatalytic performance for methanol electro-oxidation. Notably, among all the prepared AgPtM (M=Ru, Ir, Sn) catalysts, the AgPtRu exhibits the best mass activity, ∼ 3.7 and ∼1.65 times higher than that of Pt/C and AgPt nanotroughs counterpart, respectively. This study not only develops a new promising electrocatalyst for methanol oxidation, also provides method guidance for the construction of advanced Pt-based tri-metallic electrocatalysts in practical direct alcohol fuel cell.

Eco-friendly fabrication of V2O5@GO hybrids for direct glucose electrooxidation and sensing: An alternative to noble metals

In the search for efficient electrocatalysts for the electrooxidation of glucose, we present a hybrid nanomaterial V2O5@GO whose GO is obtained from by environmentally friendly electrochemical exfoliation of graphite. In a 0.01 M NaOH environment, the novel hybrid material showed clear electrooxidation peaks. The forward scan was consistent with the hydrogen abstraction reaction mechanism, while the reverse scan followed the chemisorption model. Notably, at 0.25 V, the hybrid showed better glucose electrooxidation performance in the reverse scan compared with previously reported electrodes based on noble metals, thus highlighting the importance of the electrochemical exfoliation process. With a consistent linear anodic current response at glucose concentrations from 0.5 to 7.5 mM, the V2O5@GO material proves to be a promising and cost-effective alternative for glucose sensors and biofuel cell applications.

Large scale uniform Ni-P plated carbon fiber for boosting urea electro-oxidation and electro-detection.

Seeking an excellent electrocatalyst is the trickiest issue for the application of urea electro-oxidation and electro-detection. Phosphorus-doped nickel plating on carbon fibers (Ni-P/CF) is synthesized by simple electroless plating. SEM results exhibit that the Ni-P densely and uniformly grows onto the surface of carbon fibers (CF), forming carbon fibers-like nanoarchitectures. Benefiting from the carbon fibers-like nano architectures with abundant exposed active sites on the surface of CF, electron transfer can be synchronously facilitated, and Ni-P/CF displays superior urea electrooxidation (UOR) performance with potentials of 1.40V to reach 100mAcm-2. Impressively, it can maintain at 20mAcm-2 for 48h without evident activity attenuation, demonstrating robust durability. Cycle stability shows that the voltage has only increased by 10mV at 300mAcm-2 from the 10th to 20000th cycles. Most importantly, Ni-P/CF at a length of 100cm with good reproducibility was successfully synthesized, denoting great potential for large-scale industrial production. Therefore, this work not only affords cost-effective tactics for urea-rich wastewater degradation but also can achieve practical medical applications.

Co-reduction assisted fabrication of PdCuTe nanowires for enhanced glycerol electrooxidation

High-performance electrocatalysts for glycerol oxidation are highly craved for the direct glycerol fuel cells. Herein, trinary PdCuTe nanowires with well-defined nanostructure was prepared through a co-reduction assisted approach with Te nanowires as the starting template. The addition of ascorbic acid is the key for introduction of Cu into the PdTeCu nanowires during synthesis. Electrochemical results revealed that the incorporation of Cu could enhance the performance for glycerol electrooxidation, which rendering the as-fabricated PdCuTe nanowires afford the highest current density of 61.1 mA cm−2. Owe to the improved electrooxidation kinetics and reduced charge transfer resistance, the resultant PdCuTe nanowires also demonstrated a better long-term stability. The synthetic strategy proposed herein is useful for the preparation of other materials, and the developed catalysts herein may also find wide applications in electrochemical-related fields.

Tuning electronic structure of Pt to enhance ethanol electrooxidation performance of SnO2 patched ultrathin PtRhNi nanowires

Tuning electronic structure of Pt to enhance ethanol electrooxidation performance of SnO2 patched ultrathin PtRhNi nanowires

Enhancing ethanol electrooxidation stability catalyzed by Pt with SnO2 modified graphene as support

Developing catalysts for the stable electrooxidation of ethanol have been a goal pursued by scientists. The present work reports a facile synthesis of catalysts with a double junction structure of Pt and SnO2 on graphene (Pt/SnO2GN) through sol–gel combined with glycol hydrothermal reduction method. The physicochemical analyses show that the reduced Pt uniformly dispersed on GN is located adjacent to SnO2 and has electronic interaction with the composite carrier. The electrochemical results exhibit that Pt/SnO2GN has better catalytic performance for ethanol electrooxidation than PtSnO2/GN and PtSn/GN. The ethanol oxidation peak current density on Pt/SnO2GN, after 1500 cycles of voltammetric testing, can still maintain 99.2% of the highest. The excellent catalytic stability of Pt/SnO2GN is ascribed to the double junction structure and the appropriate interaction between Pt and SnO2 on GN, which enlarge the ECSA of Pt, improve the structural integrity, accelerate the charge transfer kinetics and increase the CO tolerance.

Waste biomass-derived N, P co-doping carbon aerogel-coated CoxFe1−xP with modulated electron density for efficient electrooxidation of contaminants

Developing low-cost, green, high-performing electrode materials to address environmental pollutants and the energy crisis is significant but challenging. Herein, the bimetallic iron cobalt phosphide coated in waste biomass-derived N, P co-doping carbon (CoxFe1−xP@NPC) is constructed. Furthermore, the active site density and the water decomposition energy barrier of surface-coated NPC are modulated by optimizing the electronic structure of CoxFe1−xP via doping engineering. The Fe-modulated CoxFe1−xP@NPC exhibits a hierarchical porous self-supporting structure and excellent physical & chemical properties with excellent electrooxidation performance, achieving over 95% removal of TCH within 60 min. The density functional theory (DFT) calculations further confirms that N carries more positive charge and P carries more negative charge in the NPC of CoxFe1−xP@NPC with Fe modulation, which can promote the adsorption and dissociation of water molecules. Of note, Co0.75Fe025P@NPC displays a low water dissociation energy barrier to produce ·OH and a high energy barrier to produce O2 than its counterparts. This study offers new insight into controllable modulation of biomass carbon-based composite electrode catalytic activity for high-efficiency degradation of contaminants.

Self-Supported 3D PtPdCu Nanowires Networks for Superior Glucose Electro-Oxidation Performance.

The development of non-enzymatic and highly active electrocatalysts for glucose oxidation with excellent durability for blood glucose sensors has aroused widespread concern. In this work, we report a fast, simple, and low-cost NaBH4 reduction method for preparing ultrafine ternary PtPdCu alloy nanowires (NWs) with a 3D network nanostructure. The PtPdCu NWs catalyst presents significant efficiency for glucose oxidation-reduction (GOR), reaching an oxidative peak-specific activity of 0.69 mA/cm2, 2.6 times that of the Pt/C catalyst (0.27 mA/cm2). Further reaction mechanism investigations show that the NWs have better conductivity and smaller electron transfer resistance. Density functional theory (DFT) calculations reveal that the alloying effect of PtPdCu could effectively enhance the adsorption energy of glucose and reduce the activation energy of GOR. The obtained NWs also show excellent stability over 3600 s through a chronoamperometry test. These self-supported ultrafine PtPdCu NWs with 3D networks provide a new functional material for building blood glucose sensors and direct glucose fuel cells.

Ultra-Low Loading of Iron Oxide and Platinum on CVD-Graphene Composites as Effective Electrode Catalysts for Solid Acid Fuel Cells

We propose a new design for electrocatalysts consisting of two electrocatalysts (platinum and iron oxide) that are deposited on the surfaces of an oxidized graphene substrate. This design is based on a simple structure where the catalysts were deposited separately on both sides of oxidized graphene substrate; while the iron oxide precipitated out of the etching solution on the bottom-side, the surface of the oxidized graphene substrate was decorated with platinum using the atomic layer deposition technique. The Fe2O3-decorated CVD-graphene composite exhibited better hydrogen electrooxidation performance (area-normalized electrode resistance (ANR) of ~600 Ω·cm−2) and superior stability in comparison with bare-graphene samples (ANR of ~5800 Ω·cm−2). Electrochemical impedance measurements in humidified hydrogen at 240 °C for (Fe2O3|Graphene|Platinum) electrodes show ANR of ~0.06 Ω·cm−2 for a platinum loading of ~60 µgPt·cm−2 and Fe2O3 loading of ~2.4 µgFe·cm−2, resulting in an outstanding mass normalized activity of almost 280 S·mgPt−1, exceeding even state-of-the-art electrodes. This ANR value is ~30% lower than the charge transfer resistance of the same electrode composition in the absence of Fe2O3 nanoparticles. Detailed study of the Fe2O3 electrocatalytic properties reveals a significant improvement in the electrode’s activity and performance stability with the addition of iron ions to the platinum-decorated oxidized graphene cathodes, indicating that these hybrid (Fe2O3|Graphene|Platinum) materials may serve as highly efficient catalysts for solid acid fuel cells and beyond.