Electrochemically active site-rich nanocomposites of two-dimensional materials as anode catalysts for direct oxidation fuel cells: new age beyond graphene

Ice-templated synthesis of tungsten oxide nanosheets and their application in arsenite oxidation

Tungsten oxide (WO₃) nanosheets were prepared as catalysts to activate hydrogen peroxide (H₂O₂) in arsenite (As(III)) oxidation. Ice particles were employed as templates to synthesize the WO₃ nanosheets, enabling easy template removal via melting. Transmission electron microscopy and atomic force microscopy revealed that the obtained WO₃ nanosheets were plate-like, with lateral sizes ranging from dozens of nanometers to hundreds of nanometers and thicknesses of <10 nm. Compared to that of the WO₃ nanoparticle/H₂O₂ system, a higher efficiency of As(III) oxidation was observed in the WO₃ nanosheet/H₂O₂ system. Electron spin resonance spectroscopy, radical quenching studies, and As(III) oxidation experiments under anoxic conditions suggested that the hydroperoxyl radical (HO₂^●) acted as the primary oxidant. The WO₃ nanosheets possessed numerous surface hydroxyl groups and electrophilic metal centers, enhancing the production of HO₂^● via H₂O₂ activation. Various anions commonly present in As(III)-contaminated water exhibited little effect on As(III) oxidation in the WO₃ nanosheet/H₂O₂ system. The high oxidation efficiency was maintained by adding H₂O₂ when it was depleted, suggesting that the catalytic activity of the WO₃ nanosheets did not deteriorate after multiple catalytic cycles.

Metalated covalent organic frameworks: from synthetic strategies to diverse applications

Covalent organic frameworks (COFs) are a class of organic crystalline porous materials discovered in the early 21st century that have become an attractive class of emerging materials due to their high crystallinity, intrinsic porosity, structural regularity, diverse functionality, design flexibility, and outstanding stability. However, many chemical and physical properties strongly depend on the presence of metal ions in materials for advanced applications, but metal-free COFs do not have these properties and are therefore excluded from such applications. Metalated COFs formed by combining COFs with metal ions, while retaining the advantages of COFs, have additional intriguing properties and applications, and have attracted considerable attention over the past decade. This review presents all aspects of metalated COFs, from synthetic strategies to various applications, in the hope of promoting the continued development of this young field.

Enabling methanol oxidation by interacting hybrid nano system of spinel Co3O4 nanoparticles decorated MXene

For the successful implementation of direct methanol fuel cells in the commercial applications, highly efficient and durable non-noble electrocatalyst based on conducting and stable non-carbonaceous support can be a potential...

Graphene incorporated mesoporous perovskite with excellent conductivity and catalytic activity for low temperature solid oxide fuel cells

In modern times, energy transformation sources with superior efficacy and eco-friendliness have become remarkably attractive in terms of fuel cell technology.

Simultaneous removal of organics and bioenergy production by microbial fuel cell: modeling approach

In this study, membrane less double chambered microbial fuel cell has been used for the simultaneous electricity generation and organics removal from glucose and glutamic acid (mole ratio 1:1) based synthetic solution in the presence of municipal wastewater activated sludge-based microbes using graphite as an electrode. A central composite design technique has been employed to optimize the experimental conditions using design expert software for modeling input–output model as surface function of various input parameters like initial COD, anodic pH, and run time for voltage and current density generation. The predicted model suggests that maximum voltage and current density generation of ∼14.8 mV and ∼41.11 μA/m2, respectively are obtained at COD: 1500 mg/L, pH: 7, run time: 7 days. Further, methylene blue is used as mediator for voltage and current density production at optimum condition. Experimental result depicts the substantial role of mediator concentration and showing maximum current and voltage production, approximately 10 times higher than that without meditator under similar conditions. In addition to bioenergy production, values of BOD and COD in the wastewater simulant are found to be reduced after each run which exists below the permissible limits. The developed model equations give better prediction on the voltage and current density generation which lies within the error limits of −12 to +12% and −2 to 14%, respectively to their corresponding experimental values. Overall, the process can generate simultaneously bioenergy along with wastewater treatment and the empirical model gives better prediction with experimental values.

Mxene coupled over nitrogen-doped graphene anchoring palladium nanocrystals as an advanced electrocatalyst for the ethanol electrooxidation

Development of good support materials is widely adopted as a valid strategy to fabricate high performance electrocatalysts for the ethanol oxidation reaction (EOR). In this study, the small diameter Ti₃C₂T_x MXene thin nanosheets inserted into three-dimensional nitrogen-doped grapheme (NG) was constructed via a facile hydrothermal method and employed as support materials for anchoring Pd nanocrystals (Pd/Ti₃C₂T_x@NG). The obtained-Pd/Ti₃C₂T_x@NG as EOR electrocatalyst in alkaline media outperforms the commercial Pd/C with better electrocatalytic activity, enhanced long-term stability and high CO tolerance. The Ti₃C₂T_x inserted into NG probably plays a key role for enhancing the properties of the synthesized-catalyst. Inserting Ti₃C₂T_x into NG allows the electrocatalysts to have high porosity, surface hydrophilicity, sufficient number of anchor sites for Pd nanocrystals and modifies its electronic properties, which can promote the electrocatalytic activity and durability. The enhanced EOR performance endows Pd/Ti₃C₂T_x@NG with great application potential in fuel cells as an anode catalyst. Furthermore, the prepared Ti₃C₂T_x@NG is also suitable in various desired applications, especially other oxidation reactions.