Electrocatalysis最新文献

In this work, we proposed a novel 3D-printed manufactured electrode system. A project was developed and optimized, compatible with commercially available potetiostats. Additive manufacturing included the modification of the pseudo-reference electrode by electrodeposition of silver and its subsequent oxidation to the Ag/AgCl form. Then the system was tested using electrochemical techniques to check the application as a universal electroactive platform. As an example, we checked the detection of paracetamol as a common substance from non-steroidal anti-inflammatory drugs (NSAIDs). Finally, the system was compared to available commercial carbon electrodes, considering the screen-printed electrode (SPE no.1 and SPE no.2) and the glassy carbon electrode (GCE), showing higher sensitivity and linearity range compared to commercial screen-printed systems. The novelty of the proposed platform unveils a new way of common, simple, budget, and fast obtaining a universal electroactive platform for electrochemical research, keeping high-performance parameters.

Electrocatalytic reduction of CO₂ can convert CO₂ into a variety of carbon-based fuels and achieve carbon neutrality. Tin oxide (SnO₂) electrocatalytic materials have the advantages of low cost and low toxicity, and the electrocatalytic reduction of CO₂ to formic acid is highly selective. In this paper, Pd-doped SnO₂ nanoparticle materials were synthesized by flame spray pyrolysis and their properties for electrocatalytic reduction of CO₂ to formic acid were explored in a gas diffusion electrolytic cell. The results showed that the Pd/SnO₂ catalysts could improve the catalytic activity for the conversion of CO₂ to formate, and the most superior 0.5 Pd/SnO₂ showed a Faraday efficiency of 63% for formate at − 1.20 V vs. RHE and a current density of 90.59 mA^.cm⁻², which were 1.4 and 2.7 times higher than that of pure SnO₂, respectively. The modified catalyst grains were refined, and the charge transfer resistance at the catalyst interface was reduced, and the electrochemically active area was increased, generating more catalytically active sites and increasing the contact between CO₂, electrolyte, and electrode-catalyst. Density functional theory calculations showed that the doping of Pd element changed the local structure of SnO₂, and the Pd/SnO₂ surface was more favorable for the generation of the intermediate products ^*HCOO⁻ and formate as well as the inhibition of hydrogen precipitation, which was consistent with the experimental results.

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Herein, poly(methacrylic acid) (PMAA) and PMAA-g-carbon nanotube (CNT) (PMC) hydrogel composites were prepared using the redox polymerization method. PMAA and PMC hydrogel composites were coated with the Ru metal electrochemical deposition method to be used as electrocatalysts in water-splitting applications. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy–energy dispersive X-ray (SEM–EDX) and mapping, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques were used to characterize the hydrogel composites. The electrochemical properties of these hydrogel composites were examined using techniques including linear sweep voltammetry (LSV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) measurements. The activities of hydrogel composites against both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) were examined for water-splitting applications. The electrochemical results indicated that the Ru/PMC hydrogel composite exhibited high catalytic activity for both OER and HER in alkaline media.

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Protective-shell catalysts (particularly carbon-capped catalysts) may increase the durability of oxygen reduction catalysts, owing to their supposed anti-degradation effect. The mechanisms promoting this effect are still questioned and further scientific scrutiny is needed to better understand their underlying principle. In this paper, three carbon-capped PtNi/C catalysts with different extents of carbon cap graphitization were synthesized via a one-pot heat treatment. A precise electrochemical activation was applied, leading to similar intrinsic ORR activity than for a commercial Pt₃Ni/VC benchmark catalyst and larger activity than for the mother platinum nanoparticles supported on graphitized carbon (Pt/Gr.C) catalyst. To examine their robustness once fully activated, an aggressive accelerated stress test (AST) designed to emphasize Pt dissolution/redeposition, was performed and coupled with post mortem analyses. The carbon-capped catalyst with the most graphitized shell is able to withstand the AST: its Pt nanoparticle size is less affected than for uncapped catalysts, suggesting a positive action of the protective carbon cap.

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As energy resources become increasingly scarce and environmental issues grow more pressing, hydrogen is emerging as a promising alternative to traditional fuels. In this work, rod-shaped NiMoO₄-Sx-c electrolytic water HER catalysts with surface particles attached were prepared by solvothermal vulcanization and calcination reduction based on the configuration of NiMoO₄ precursors with different NiMo atom ratios. NiMoO₄ Sx-c achieved current densities of 10 mA cm⁻² and 100 mA cm⁻² at overpotentials of 105 mV and 256 mV, respectively. At 100 mA cm⁻², the catalytic performance of the electrode did not change within 50 h, which proved that the treated catalyst had excellent stability. The excellent HER performance was attributed to the formation of cross-linked NiS₂ and MoS₂ heterostructures on its surface due to the vulcanization and calcination reduction processes, thereby increasing the H adsorption energy. Concurrently, during the vulcanization process, particles were deposited on the surface of the smooth rod-like structure, which improved the hydrophilic/hydrophobic properties of the catalyst, enhanced the diffusion of the electrolyte, and ensured the rapid release of bubbles. This research not only provides a new strategy for synthesizing efficient HER electrocatalysts but also promotes the development of efficient electrolytic water catalysts.

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Transition metals from the d-group, specifically Fe, Co, and Ni, have demonstrated exceptional electrocatalytic performance as non-noble metal electrocatalysts for water splitting in alkaline electrolytes. In this study, nanostructured Ni-Co alloy electrocatalysts were synthesized using a chemical coprecipitation-thermal method and tested in a 1 M KOH alkaline solution. Five distinct nano-Ni-Co alloy electrodes, each with unique morphologies and structures, were fabricated by varying the composition. The nano-Ni-Co alloy facilitates the adsorption and desorption of H⁺ and OH⁻ ions, thereby enhancing the efficiency of hydrogen and oxygen evolution reactions (HER and OER). Among the tested alloys, the NiCo1 alloy exhibited outstanding electrocatalytic activity in alkaline media, with overpotentials of 267.6 mV for HER and 158.5 mV for OER at 40 mA cm⁻². This work demonstrates a simple and effective synthetic route for integral water decomposition, highlighting the potential of Ni-Co alloys for practical applications in the energy sector.

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The ubiquitous and indispensable nature of ascorbic acid, commonly known as vitamin-C, has spurred significant interest in developing precise and efficient biosensing techniques for its detection. As an essential micronutrient and potent antioxidant, the monitoring of vitamin-C levels holds importance in maintaining human health and preventing various diseases for that we have synthesis the novel Nickel doped Molybdenum Oxide (Ni-MoO₃) on reduced graphene oxide composite by hydrothermal method. This study extensively investigates the composite’s phase composition, morphology, surface area, and functional groups using various characterization techniques. The electrochemical studies exhibit the nanocomposites favorable electrochemical reversibility, low charge transfer resistance (R_ct), and enhanced double-layer capacitance (C_dl). Importantly, the Ni-MoO₃/rGO nanocomposite exhibited noteworthy electro-catalytic performance. These findings highlight the potential of synthesized composite as an efficient electro-catalyst with promising applications in energy conversion and storage technologies. The synthesized Ni-MoO₃/rGO was drop coated on a screen-printed carbon electrode (SPCE) nanocomposite electrode, which was used to measure ascorbic acid and vitamin-C tablet, a commercial tablet for its commercial usage, with a linear range of 50–400 µM and a potential range of 0.0 to 1.5 V by using two samples: ascorbic acid with LOD = 3.1268 mM, and LOQ = 5.473 mM at pH-7 phosphate buffer solution with sensitivity of 0.1739 µAµM⁻¹ cm⁻².

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Abundant use of aluminum cookware and treatment of high fluoride-containing water with aluminum salts results in the discharge of aluminum ions into water bodies and food items, causing harmful effects on human health. Herein, an electrochemical sensor for sensing the Al (III) ions by modification of glassy carbon electrode (GCE) with Schiff’s base ligand as an electrocatalyst and activated charcoal as an electro-conductive material is being reported. The response is recorded via Square wave voltammetry (SWV) for the modified GCE, resulting in a characteristic peak at potential 0.4 V due to the interaction of the Al (III) ions with the electrocatalyst. The peak current intensity increases linearly in the concentration range from 0.1 – 50 µM (R² = 0.994), and the detection limit of 45 nM (S/N = 3) was calculated. DFT calculation reveals that the energy gap between the HOMO and LUMO decreases from 0.551 eV to 0.303 eV after the complexation of the ligand with the Al (III) ions indicating the stability enhancement after complex formation. Common interfering agents do not significantly change in the peak current intensity, demonstrating excellent selectivity. Spiking Al (III) ions in tap and river water checked practical applicability, which gave satisfactory recovery results.

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Developing efficient and cost-effective oxygen reduction reaction (ORR) catalysts is critical for advancing fuel cell technologies. Based on this, we propose a metal-free reduced graphene oxide (rGO) catalyst produced from graphite as a base material for electrode modification. Nevertheless, by using phenanthroline as a nitrogen precursor, we investigated different synthesis conditions to adjust the electrocatalytic characteristics of the material precisely, aiming for a four-electron mechanism with low onset potential. A comprehensive experimental design revealed that specific preparation parameters (75 mg of phenanthroline, 1079 °C, and 1.73 h) significantly influenced the catalyst’s performance: the optimized catalyst had an increase in current density and a positive shift in the half-wave potential compared to other materials that underwent not optimized synthetic conditions. Morphological and physicochemical characterizations, including SEM and XPS analyses, provided insights into the material’s structure and composition, correlating the observed catalytic performance with graphitic nitrogen and an optimized degree of deoxygenation. Crucially, our study demonstrated a method for achieving varied levels of nitrogen species with the same nitrogen precursor, revealing that, under optimized conditions, the same precursor can yield diverse outcomes. Importantly, the optimized catalyst demonstrated impressive performance, showing only a 0.1 V difference in onset potential compared to the commercial Pt/C catalyst and a limiting current density of 2.1 mA cm⁻². Thus, this study underscores the importance of systematic experimental design and optimization in developing high-performance, metal-free electrocatalysts for energy conversion applications.

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The inherent disadvantages of carbon-based anodes, including their low hydrophilicity, significant charge transfer resistance, and limited power density, hinder their widespread commercial utilization in microbial fuel cells (MFC). Addressing these challenges, this study involved the surface modification of a carbon-based anode. To improve the adhesion of electroactive microorganisms (EAM) on the anode surface and increase the extracellular electron transfer rate, CNT@Ti₃C₂T_xMXene was applied to the surface of carbon cloth (CC) using drip coating. Initially, we conducted a comprehensive investigation on the optimal amount of modification required. To achieve this, we designed four distinct groups of modified electrodes. Through electrochemical analysis and phase characterization, it was determined that a modification dosage of 1.5 mg/cm² for CNT@Ti₃C₂T_xMXene/CC electrodes yielded the most optimal electrical conductivity and the highest capacitance. The Rs of CC is reduced from 1.48 to 0.55 Ω and the Rct from 2.62 to 2.09 Ω, and the capacitance is increased from 3.98 10⁻⁰⁷F to 9.11 10⁻⁰⁶F. Subsequently, the CNT@Ti₃C₂T_xMXene/CC with a modification of 1.5 mg/cm² was used as the anode of the microbial fuel cell. The modification of CNT@Ti₃C₂T_xMXene improved the power generation performance. The maximum output voltage of the MFC was increased from 546 to 709 mv, and the power density was increased from 44.9 to 101.8 mW/m². The underlying factor lies in the ability of CNT@Ti₃C₂T_xMXene/CC to significantly lower the internal resistance within the microbial fuel cell, thereby fostering the development of biofilm. Notably, our observations revealed that the biofilm formation was particularly facilitated on the anode surface of CNT@Ti₃C₂T_xMXene/CC. In essence, the CNT@Ti₃C₂T_xMXene-modified carbon cloth not only minimizes internal resistance but also enhances the electroactive surface area, exhibiting superior electrical conductivity. These attributes make it an advantageous material for biological applications.

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