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•Facile electrodeposition of Nickel and Polydiphenylamine on Fluorine tin-doped electrode.•Synergistic effect between Nickel and PDPA enhanced methanol and ethanol ...electrooxidation.•Rct value of Ni/PDPA is relatively lower than PDPA alone, indicating lower charge resistance.•Enhanced stability of Ni/PDPA compared to PDPA.•Ni/PDPA is highly cost-effective compared to platinized electrode material for DAFCs.
Methanol and ethanol oxidation in fuel cells is considered an alternative effective renewable energy. In this work, we investigated the electrooxidation of methanol and ethanol using a novel nanohybrid material consisting of polydiphenylamine (PDPA) and nickel (Ni) nanoparticles onto fluoride doped tin oxide (FTO) electrode using a facile electrodeposition method. The fabricated electrode was well-characterized using X-ray diffraction, field-emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy techniques, and Fourier-transform infrared spectroscopy to confirm Ni/PDPA formation. Electrochemical measurements were carried out in 0.1 M KOH, and Ni/PDPA demonstrated excellent electrocatalytic activity due to synergistic effect owing to relatively lower onset potential by Ni and high conductivity of the conductive polymer. In addition, Ni/PDPA catalysts exhibited high current density, relatively low Rct value, and better stability. Based on the obtained electrochemical results, it is confirmed that Ni/PDPA catalysts synthesized via electrodeposition are time-saving, economically viable, and suitable for fuel cell applications, particularly in direct alcohol fuel cells.
Here, we present the fabrication of a reduced graphene oxide-supported PdCa (PdCa/rGO) alloyed catalyst via a NaBH4 reduction method for direct alcohol fuel cells in basic medium and direct formic ...acid fuel cells in acidic medium. Powder X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller, inductively coupled plasma mass spectrometry, and Raman spectroscopy are used to characterize the PdCa/rGO catalyst. We proved that the calcium oxide significantly enhances the electrocatalytic methanol, ethanol, and formic acid oxidation over the Pd/rGO surface. The obtained mass activities for PdCa/rGO are 4838.06, 4674.70, and 3906.49 mA mg–1 for formic acid, methanol, and ethanol, respectively. Long-term stability, high activity, and high level of tolerance to CO poisoning of the PdCa/rGO electrocatalyst are attributed to the presence of calcium oxide. These results prove that the PdCa/rGO catalyst has improved electrocatalytic performance for the oxidation of formic acid, methanol, and ethanol with reference to the Pd/rGO.
Ni-doped CoTe nanorods have been prepared for 5-hydroxymethylfurfural oxidation reaction. The doping of Ni facilitates the oxidation of Co2+ to high-valent CoO2 to achieve efficient electrosynthesis ...of the valuable 2,5-furandicarboxylic acid.
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•A crude nanorod structure CoNiTe was prepared by two-step hydrothermal reactions for HMFOR.•Ni doping modulates the electronic structure of Co and improves the electrocatalytic performance of CoNiTe.•The generation of high-valent cobalt is the key for excellent HMFOR.
Replacing the anodic oxygen evolution reaction (OER) in water splitting with 5-hydroxymethylfurfural oxidation reaction (HMFOR) can not only reduce the energy required for hydrogen production but also yield the valuable chemical 2,5-furandicarboxylic acid (FDCA). Co-based catalysts are known to be efficient for HMFOR, with high-valent Co being recognized as the main active component. However, efficiently promoting the oxidation of Co2+ to produce high-valent reactive species remains a challenge. In this study, Ni-doped CoTe (CoNiTe) nanorods were prepared as efficient catalysts for HMFOR, achieving a high HMFOR current density of 65.3 mA cm−2 at 1.50 V. Even after undergoing five successive electrolysis processes, the Faradaic efficiency (FE) remained at approximately 90.7 %, showing robust electrochemical durability. Mechanistic studies indicated that Ni doping changes the electronic configuration of Co, enhancing its charge transfer rate and facilitating the oxidation of Co2+ to high-valent CoO2 species. This work reveals the effect of Ni doping on the reconfiguration of the active phase during HMFOR.
It is a crucial and current challenge to develop efficient metal sulfide bifunctional electrocatalysts for practical applications in direct borohydride-hydrogen peroxide fuel cells (DBHPFCs). In this ...study, a uniform nanoflower-like Ni3S2 is rationally designed and hydrothermally grown on the surface of a 3D nickel foam (NF) support without the need for additional nickel sources, and Pd nanoparticles are further reduced on the surface of nanoflower-like Ni3S2 with sulfur vacancies to form Pd/v-Ni3S2/NF electrode by NaBH4 reduction. The Pd/v-Ni3S2/NF electrode delivers a NaBH4 electrooxidation current density of 902 mA cm−2 at 0.85 V and a H2O2 electroreduction current density of 298 mA cm−2 at 0.65 V in alkaline solutions. Subsequently, Pd/v-Ni3S2/NF electrodes are assembled into DBHPFCs, yielding the optimal power density of 78 mW cm−2 and demonstrating superior long-term stability. These results fully indicate that the nanoflower-like Pd/v-Ni3S2/NF self-supported electrode with abundant sulfur vacancies is a promising bifunctional electrocatalyst for DBHPFCs.
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•Pd/v-Ni3S2/NF was rationally designed by using a simple fabrication process.•Pd/v-Ni3S2/NF electrode delivers a NaBH4 oxidation current density of 902 mA cm−2.•Pd/v-Ni3S2/NF electrode delivers a H2O2 reduction current density of 298 mA cm−2.•Pd/v-Ni3S2/NF was assembled into a DBHFC with higher power density of 78 mW cm−2.•Sulfur vacancy exposed more active sites to achieve super performances.
Electrochemical transition metal catalysis is a powerful strategy for organic synthesis because it obviates the use of stoichiometric chemical oxidants and reductants. C–H bond functionalization ...offers a variety of useful conversions of simple and ubiquitous organic molecules into diverse functional groups in a single synthetic operation. This review summarizes recent progress in merging electrochemistry with transition metal-catalyzed C–H functionalization, specifically C–C, C–X (halogen), C–O, C–P, and C–N bond formation.
Herein, palladium-cobalt supported on ketjenblack (PCKB) electrocatalyst is synthesized and tested i) for the reaction of glucose electrooxidation (GOR) in presence of dopamine and uric acid and ii) ...for the simultaneous detection of the above three substances. The electrocatalyst, prepared using the sulphite complex method, is physicochemically characterized by X-Ray diffraction (XRD), transmission electron microscopy (TEM) and X-Ray photoelectron spectroscopy (XPS) and electrochemically characterized by cyclic voltammetry, potentiometry and chronoamperometry.
It is found that the electrocatalytic activity towards GOR: i) is favoured in case of ketjenblack support, ii) is enhanced more when Co is added into Pd, iii) is enhanced with temperature increment from 26.0 to 42.0 °C, iv) is enhanced when glucose concentration increases up to 1.5 mM, while at higher concentration values is suppressed. The electrocatalyst ability of simultaneous glucose, dopamine and uric acid electrooxidation is attributed to the bi-functional role of the PCKB due to cobalt presence.
•Glucose oxidation reaction (GOR) is more favoured using as support ketjenblack (KB) than vulcan-XC72.•Pd10Co1/KB favours GOR, even in presence of dopamine (DA) and uric acid (UA).•Dopamine (DA) and uric acid (UA) are also electrooxidated on Pd10Co1/KB.•Pd10Co1/KB is able to co-detect dopamine (DA), uric acid (UA) and glucose (Glu).
Direct ethanol fuel cells (DEFCs) are promising power sources for portable electric devices owing to their high energy conversion efficiency and easy transportation of fuels. However, most ...electrocatalysts for DEFCs suffer from serious CO poisoning and low selectivity toward the C–C bond cleavage. Herein, we report a class of subnanometer platinum–rhodium nanowires (Pt–Rh NWs) as highly efficient electrocatalysts toward ethanol oxidation reaction (EOR). The prepared PtRh NWs have ultrathin features with an average diameter of only 1.2 nm, largely promoting Pt utilization efficiency. Combining the structural effect and synergistic effect, the optimized PtRh NWs/C shows nearly three times enhancement in activity and promoted stability for EOR compared with commercial Pt/C. Detailed mechanism studies reveal that the introduction of Rh can evidently improve the antipoisoning ability, and the PtRh NWs/C shows enhanced C–C bond cleavage ability with significant C1 pathway selectivity, all of which collectively enhance the EOR electrocatalysis.
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•Landfill leachate was efficiently treated by a sequential process (EC + EO + SR-AOP).•Sequential process removed 95.6 and 99.8% of COD and ammonia respectively.•Phytotoxicity was ...reduced after each process treatment.•Biodegradation of the final effluent was improved significantly.
Landfill leachate is well known as one of the most serious environmental problems due to the high concentrations of organic and inorganic compounds. Several methods have been reported for the treatment and detoxification of landfill leachate. However, high organic load and the presence of refractory organic pollutants resulted in inefficiency of those methods when at least applied alone. The present work recommended a sequence of processes: electrocoagulation (EC), electrooxidation (EO) and peroxymonosulfate (PMS)/UV/CuFe2O4 (sulfate radical-based advanced oxidation process, SR-AOP) for treatment of landfill leachate. A parametric evaluation was conducted for each process including pH, current densities, electrode type, catalyst loading, PMS dosage and reaction time. Al and Fe electrodes for the EC process and Pt, PbO2 and graphite for the EO process were investigated. The results showed that Fe and PbO2 were more efficient than other electrodes for EC and EO respectively. COD removal efficiencies were up to 60.0, 50.0 and 77.9% for EC, EO and SR-AOP, respectively. Removal efficiencies for the sequential process were 95.6, 90.5, 91.6 and 99.8% for COD, TOC, BOD and ammonia (NH4-N) respectively. Biodegradability was significantly enhanced according to the BOD/COD ratio and the average oxidation state of carbon (AOSC). Biodegradation test indicated that the organic matter was completely degraded by activated sludge in seven days. Phytotoxicity experiments also demonstrated a considerable reduction in phytotoxicity after each process. The results confirmed that the proposed sequence is efficient for COD removal, phytotoxicity reduction and biodegradability improvement being an acceptable treatment for landfill leachates.
Platinum (Pt) is often used as an electrocatalyst in the electrooxidation of ethanol. There have been many attempts to improve the catalytic properties of platinum-based catalysts to achieve ...satisfactory results. The solutions are manipulating the size and shape of Pt. In this study, Pt will be deposited using the square wave pulse deposition method at upper potential variations. The Pt samples were characterized by scanning electron microscopy (SEM), X-ray diffraction, energy dispersive X-ray, and electrochemical impedance spectroscopy. The results of SEM show that the morphology of Pt at potentials of 0.3 V, 0.5 V, and 1.0 V produces a dendritic nanothorn morphology, while 1.25 V and 1.50 V produce a nanoleaf morphology. The lowest charge transfer resistance value is at Pt1.0V with the smallest size. The highest yield of ethanol electrooxidation was at Pt1.0V reaching 8.82 mA/cm2.
