The production of hydrogen by water electrolysis fundamentally requires growth of strong and effective oxygen evolutional electrocatalysts. Transition metal selenides, comprising of earth abundant ...elements have attracted regards as superb electrocatalysts for oxygen evolution reaction (OER) in the alkaline electrolyte. Toward defeat the huge overpotential for OER, in this manuscript we investigate the expansion of Fe doped cobalt-diselenide (Fe-CoSe2) nanostructure over 3D nickel foam (NF) through a simple and scalable electrodeposition technique. The prepared Fe-CoSe2/NF electrode demands an overpotential of only 220 and 256 mV to attain the current density of 10 and 100 mA cm−2, respectively. Moreover, the Fe-CoSe2/NF exhibits negligible tafel slope (35.6 mV dec−1) and good stability.
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•One-step electrodeposition method has been used to prepare Fe doped CoSe2.•Electrodeposited Fe doped CoSe2 attains the topmost activity for OER in 1.0 M KOH.•Prepared Fe doped CoSe2 electrode is very stable for OER process.
Iridium based materials are one of the most active electrocatalysts used for the oxygen evolution reaction (OER) in polymer electrolyte membrane (PEM) water electrolysers. To increase the ...utilization, the iridium electrocatalyst is typically dispersed on a high-surface area support material. This results in less iridium being required and consequently reduced catalyst cost. In this work, six metal carbides and oxides were characterized and evaluated as supports for iridium electrocatalyst. The supports studied included: tantalum carbide (TaC), niobium carbide (NbC), titanium carbide (TiC), tungsten carbide (WC), niobium oxide (NbO2), and antimony-doped tin oxide (Sb2O5-SnO2).
The rational design and controllable manufacture of electrocatalyst for pH-insensitive hydrogen evolution reactions (HER) based on the abundant elements of the earth is a critical, urgent and ...challenging task. Herein, a curved trapezoidal nanosheet structure on conductive Ni-Co support (Cu3P/NiCoP/NCF) was designed and fabricated as a novel electrocatalyst for HER, benefiting from the synergism effect between Cu3P and NiCoP phases, the optimal electronic structure, the intrinsic low resistance of the bimetal substrate and the uniform trapezoidal nanosheet structure. The self-supported Cu3P/NiCoP/NCF composite catalyst exhibits excellent electrocatalytic performance for HER in a wide pH range with the overpotentials of 51 mV, 87 mV, and 151 mV at the current density of 10 mA cm−2 in alkaline, acidic and neutral electrolytes, respectively. Impressively, the fabricated Cu3P/NiCoP/NCF catalyst shows ultra-stable electrocatalytic performance and good durability in HER processes. What's more, the Cu3P/NiCoP/NCF could achieve a high current density of at least 300 mA cm−2 in alkaline. This innovative combination of the approach is expected to contribute a feasible strategy to the cause of human energy progress and is promising well beyond the water electrolysis field.
Two-dimensional MoS2 nanosheets (NSs) with high active site density were designed for the hydrogen evolution reaction (HER) through a microdomain reaction method. The effect of the annealing ...temperature on the microstructure and the HER performance of MoS2 NSs was examined, and a plausible relation between the stack structures of the MoS2 catalysts and their HER performance was also explored. The MoS2 NS electrocatalyst obtained at 550 °C reveals the best HER performance with a relatively small Tafel slope of 68 mV/dec. Both the exposed surface area and active site density are very important for providing a large amount of active sites. The present work has been proved to be an efficient route to achieve a high active site density and a relatively large surface area, which might have potential use in photoelectrocatalytic water splitting.
The electrochemical oxygen evolution reaction (OER) highly depends on the phase structure of catalysts. Herein, the CoNiFe-based sulfides are fabricated by a surface decoration on NiFe Prussian blue ...analogue, followed by an evaporating sulfurization process. The as-formed metal sulfides have a nanocubic morphology and show a phase-dependent OER activity in alkaline electrolyte. The optimized catalyst possesses a remarkable activity and durability towards OER, featured by a low overpotential of 288 mV at 10 mA cm−2 and a small Tafel slope of 72 mV dec−1. The outstanding OER performance originates from the hierarchically porous architecture and interfacial coupling between CoS2 and (Ni,Fe)S2 phases. Our finding provides a promising strategy to develop advanced low-cost electrocatalysts with intriguing phase structure by producing the heterojunctions via post treatments on PBA such as surface modification and evaporation sulfidization.
A post decoration-vaporization route is used to prepare CoNiFe-based sulfides as OER electrocatalysts with phase-dependent catalytic activities, benefiting from an integrated coupling of phase interface and hierarchically porous structure. Display omitted
•Fabrication of CoNiFe metal sulfides via post treatments over Prussian blue analogue.•Heterostructured catalysts with varied phase compositions via a temperature control.•Intriguing phase-dependent OER activities in 1.0 M KOH for as-formed catalysts.•Boosted catalytic activity by integrating phase interface and hierarchical structure.
Antibiotic pollution causes worldwide concern due to its more apparent consequences, namely antibiotic resistance and destruction of the environment. Extensive use of antibiotics in human and ...veterinary drugs releases a significant amount of toxins into the sphere of living matter, causing adverse ecological impacts. This requires the design of new analytical protocols for the effective mitigation and monitoring of hazardous pharmaceutical products to reduce the environmental burden. Therefore, we present here the hydrothermal synthesis of samarium vanadate/carbon nanofiber (SmV/CNF) composite for the determination of sulfadiazine (SFZ). The synergistic effect arising from the combination of SmV and CNF accelerates charge transfer kinetics along with the creation of more surface-active sites that benefit effective detection. The structural and compositional disclosure indicates the high purity and superior attributes of the composite material that possesses the ability to improve catalytic performance. The proposed SmV/CNF sensor exhibits important static characteristics such as wide linear response ranges, low detection limit, high sensitivity and selectivity, and increased stability. To the best of our knowledge, this is the first report on the electrochemical performance of SmV/CNF, establishing its potential application in real-time analysis of environmentally hazardous contaminants.
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•An electrochemical sulfadiazine sensor was fabricated based on SmV/CNF/GCE.•This sensor showed high sensitivity, lower LOD and good selectivity.•The nanocomposite enhanced performances of detecting sulfadiazine.•Real-time monitoring is done in water, milk, and human urine samples.
We successfully decorated SnO2 quantum dots (SQDs) on the surface of spinel cobalt ferrite (CFO) at room temperature by cost-effective method. Pristine CFO and CFO nanocomposites (CFO-Sn1 and ...CFO-Sn2) were used as an electrocatalyst for methanol oxidation reaction (MOR) and oxygen evolution reaction (OER). CFO-Sn2 led to superior MOR and OER in alkaline media owing to the improved conductivity and higher electrochemically active surface area compared to the pristine CFO and CFO-Sn1. CFO-Sn2 exhibited the highest anodic peak intensity (Ipc) for MOR and significant peak separation upto 4.0 M concentration of MeOH. CFO-Sn2 exhibited the lowest overpotential value of 290 mV at 10 mA cm−2vs RHE for OER, which was the highest among the electrocatalyst, and a Tafel slope of 85 mV/dec.
Tafel plots of electrocatalysts in aqueous 1.0 M KOH electrolyte. Display omitted
•Synthesized SnO2 QDs and well decorated on the surface of the CoFe2O4 NPs.•The physicochemical properties of synthesized electrocatalysts were investigated using XRD, XPS, SEM, TEM and TGA techniques.•Alternative nobel-metal free electrocatalyst for OER and MOR.•Electrocatalysts exhibited remarkable MOR and OER activity in alkaline media.
Highlights
A novel physical approach is proposed to enhance the electrocatalytic performance by electric field.
Under the action of electric field, some stable conductive filaments consisting of ...oxygen vacancies are formed in the Ni/Co
3
O
4
film, which remarkably reduces the system resistivity.
The electric-field-treated Ni/Co
3
O
4
material exhibits significantly superior activity and stability as a bifunctional electrocatalyst for overall water splitting, and its performance exceeds the state-of-the-art electrocatalysts.
Rational design of bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with excellent activity and stability is of great significance, since overall water splitting is a promising technology for sustainable conversion of clean energy. However, most electrocatalysts do not simultaneously possess optimal HER/OER activities and their electrical conductivities are intrinsically low, which limit the development of overall water splitting. In this paper, a strategy of electric field treatment is proposed and applied to Ni/Co
3
O
4
film to develop a novel bifunctional electrocatalyst. After treated by electric field, the conductive channels consisting of oxygen vacancies are formed in the Co
3
O
4
film, which remarkably reduces the resistance of the system by almost 2 × 10
4
times. Meanwhile, the surface Ni metal electrode is partially oxidized to nickel oxide, which enhances the catalytic activity. The electric-field-treated Ni/Co
3
O
4
material exhibits super outstanding performance of HER, OER, and overall water splitting, and the catalytic activity is significantly superior to the state-of-the-art noble metal catalysts (Pt/C, RuO
2
, and RuO
2
ǁ Pt/C couple). This work provides an effective and feasible method for the development of novel and efficient bifunctional electrocatalyst, which is also promising for wide use in the field of catalysis.
The coordination environment of single-atom catalysts (SACs) plays a crucial role in determining the energy conversion efficiency of related electrochemical devices. Herein, the coordination ...environment of a series of Co-based SACs (Co1-SACs) was tuned to correlate the chemical structures of these catalysts with their electrocatalytic performance. The optimized Co1-SACs containing Co-S2N2 sites are electrocatalytically active in both the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER), which were carried out in alkaline media. The Co1-SACs containing Co-S2N2 sites exhibit high ORR activity, with an onset potential of 0.99 V vs RHE and good stability, as well as have promising application in a zinc-oxygen battery with a high power density (260 mW cm–2) and open-circuit voltage (1.50 V), remarkable tolerance to large current density, and long-term operation. The ORR of the Co-S2N2 site is attributed to the optimized electron density of the Co atom through its cocoordination with adjacent S and N atoms. Moreover, the Co1-SACs efficiently catalyze the HER, exhibiting a low overpotential (121 mV at 20 mA cm–2), a low Tafel slope (47 mV dec–1), and long-term stability. This work also provides a facile heteroatom-doping strategy to engineer the desired coordination environments in SACs for efficient electrocatalysis.
