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Oxygen evolution reaction (OER) is a vital electrochemical reaction for sustainable energy generation technologies. Due to the sluggish kinetics, exploration for an efficient non-precious metal catalyst is essential. Bimetallic nanohybrids are potential electrocatalysts for the OER due to their pore structure, large surface area, and inevitably dispersed metal centers. This work reports the synthesis of three bimetallic Ni–Co (NCMX), Fe–Co (FCMX), and Fe–Ni (FNMX) nanohybrids onto MXene for effective OER activity. An improved OER activity is observed on a plastic chip electrode (PCE) loaded with electrocatalysts. Among the synthesized electrocatalysts, NCMX exhibits excellent OER performance with an overpotential of 220 mV and a small Tafel slope of 94 mV/dec in a basic electrolyte (1 M KOH). The 3D MXenes framework promotes strong interaction with efficient charge transfer between the nanohybrids and MXene. Results demonstrate a promising recommendation for designing high-performance MXene-supported bimetallic nanohybrid electrocatalysts. • Bimetallic Fe/Ni/Co Nanohybrids on MXene have been synthesized successfully. • Uniform distribution of nanostructures on MXene. • NCMX exhibits excellent OER performance with overpotential of 220 mV. • NCMX shows the no degradation after electrochemical performance. [ABSTRACT FROM AUTHOR]

Developing a highly efficient, stable, and earth-abundant electrocatalyst for both HER and OER is essential for water splitting. Herein, we report a bifunctional electrocatalyst in the form of iron/nickel doped graphene oxide @ MXene (GMX). The GMX-based electrocatalytic materials were prepared by annealing at different temperatures in an inert atmosphere. The GMX was characterized by various analytical tools such as PXRD, FE-SEM, HRTEM, Raman spectroscopy, and XPS. All the electrocatalysts exhibit high activity when acting as OER and HER catalyst in alkaline and acidic electrolytes. GMX-500 is considered an effective bifunctional electrocatalyst, and 10 mA cm−2 current density is achieved at a low overpotential, i.e., 370 mV for OER and 470 mV for HER, respectively. This paper focuses on the progress of inexpensive and effective electrocatalysts with high activity and long-term durability for water splitting, which is relevant in power conservation. [Display omitted] • Fabrication of iron/nickel doped graphene oxide@Mxene (GMX). • GMX-500 shows good electrocatalytic activity at 10 mA cm−2. • Tafel slope observed at 70 mV dec−1 and 110 mV dec−1 for OER and HER. [ABSTRACT FROM AUTHOR]

The advancement in membrane-based separation technologies offers advantages over traditional ways. Recovery of acid from acidic waste stream is an important issue to be solved by greener route. Diffusion dialysis using anion exchange membranes (AEMs) is an energy-intensive and environment friendly process to be taken forward. Herein, we report the eco-friendly route for chloromethylation of polysulfone using chloromethyl ethyl ether (CMEE). Effect of chloromethyl ethyl ether concentration, reaction temperature, and reaction time are investigated to get maximum tethered chloromethyl group and high yield of product. Series of chloromethylated polysulfone membranes are prepared with different concentrations of graphene quantum dots (GQDs) followed by quaternization using trimethylamine. The prepared membranes are characterized by their water content, transport properties, and stabilities. Composite membranes show enhanced water uptake, ion exchange capacity, and mechanical stability compared to that of pristine membrane. Interestingly, to address the environmental impact of acids present in industrial waste, AEMs are employed for acid recovery from model waste at higher concentrations of acid and salt using diffusion dialysis. For prepared membranes, 35.5–47.5% acid recovery has been achieved in presence of metal ions. SCE-1.0 (1.0 wt % GQD/ QPSU) membrane shows the highest acid recovery (47.5%) among the membranes. Composite membranes suggest their potential utility in acidic effluent treatment via diffusion dialysis. Image 1 • Polysulfone/GQD composite AEMs have been synthesized successfully. • Composite membranes show good ionic conductivity with stability. • AEMs showed its application in acid recovery by diffusion dialysis. [ABSTRACT FROM AUTHOR]

Herein, we report sol-gel modified sulfonated poly(ether ether ketone) (SPEEK) organo-silane based composite proton exchange membranes for their suitability in direct methanol fuel cells (DMFCs). Different concentrations (0.2–1.5 wt%) of aminopropyl trimethoxysilane (APTES) are incorporated in SPEEK matrix by in-situ sol-gel method. Physico and electrochemical performances of composite membranes are enhanced by induced H-bonding interactions between free –NH 2 and –SO 3 H groups. With increase in APTES concentration to 0.8 wt%, the ionic conductivity illustrates improvement by ⁓80% while IEC and Proton conductivity (Pc) enhances by ∼21% and ∼70%, respectively than SPEEK. To further explore the feasibility of the membranes in DMFC. Methanol crossover resistance is calculated to as low as 5.30 × 10−7 cm2 s−1 and offers highest selectivity of 4.43 S s cm−3 in contrast to 12.55 × 10−7 cm2 s−1 and 0.31 S s cm−3 for SPEEK, respectively. This study reveals that the Si-SPEEK membrane is a potential alternate for DMFC. • SPEEK matrix is loaded with APTES to enhance membrane properties. • Organosilicon-based acid-base stable membranes are prepared. • 0.8 wt% APTES showed overall improved physiochemical and electrochemical properties. • H-bonding interaction improved thermal and mechanical stability. • Alternate cation exchange membrane for DMFC is prepared. [ABSTRACT FROM AUTHOR]