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Carbon-based biowaste incorporated with inorganic oxides as a composite is an enticing option to mitigate heavy metal pollution in water resources due to its more economical and efficient performance. With this in mind, we constructed manganese-doped iron oxide microflowers resembling the dandelion-like structure on the surface of cold plasma-treated carbonized rice husk (MnFe 2 O 3 /PCRH). The prepared composite exhibited 45% and 19% higher removal rates for Cu2+ and Cd2+, respectively than the pristine CRH. The MnFe 2 O 3 /PCRH composite was characterized using XRD, FTIR, FESEM, EDX, HR-TEM, XPS, BET, TGA, and zeta potential, while the adsorption capacities were investigated as a function of pH, time, and initial concentration in batch trials. As for the kinetics, the pseudo-second-order was the rate-limiting over the pseudo-first-order and Elovich model, demonstrating that the chemisorption process governed the adsorption of Cu2+ and Cd2+. Additionally, the maximum adsorption capacities of the MnFe 2 O 3 /PCRH were found to be 122.8 and 102.5 mg/g for Cu2+ and Cd2+, respectively. Based on thorough examinations by FESEM-EDS, FTIR, and XPS, the possible mechanisms for the adsorption can be ascribed to surface complexation by oxygen-containing groups, a dissolution-precipitation of the ions with –OH groups, electrostatic attraction between metal ions and the adsorbent's partially charged surface, coordination of Cu2+ and Cd2+ with π electrons by aromatic/graphitic carbon in the MnFe 2 O 3 /PCRH, and pore filling and diffusion. Lastly, the adsorption efficiencies were maintained at about 70% of its initial adsorption even after five adsorption-desorption cycles, displaying its remarkable stability and reusability. [Display omitted] • Mn-doped Fe 2 O 3 microflowers were decorated on plasma-treated biochar (MnFe 2 O 3 /PCRH). • The MnFe 2 O 3 /PCRH was thoroughly analyzed before and after Cu2+ and Cd2+ adsorption. • Kinetics, isotherms, and thermodynamic studies showed its excellent adsorption capability. • Mechanisms underlying ions adsorption by MnFe 2 O 3 /PCRH were further clarified. • The reusability of the MnFe2O3/PCRH proved its economic sustainability. [ABSTRACT FROM AUTHOR]

A paradigm for the rational design of active, abundant, and inexpensive bifunctional electrocatalysts with acceptable electrochemical energy conversion rates has yet to be achieved. Here, we describe the assembly of a superior bifunctional electrocatalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activities based on a CoMoP/Ni 3 S 2 multicomponent, heterointerface consisting of a freestanding electrocatalyst prepared by hydrothermal-phosphidation, consisting of one-dimensional Ni 3 S 2 covered with Cereus cactus–like hierarchical CoMoP nanosheets. The resulting three dimensional CoMoP/Ni 3 S 2 core-shell heterostructure exhibited remarkable HER and OER electrocatalysis, benefiting from modulated electronic structures, rapid mass diffusion, reduced charge-transfer resistance, and a larger electrochemically active surface area. Due to these superior functionalities, the CoMoP/Ni 3 S 2 requires only 96.8 mV (at η 10) for HER catalysis and 270 mV (at η 50) for an OER process. Furthermore, a stable water-splitting device using CoMoP/Ni 3 S 2 for both the anode and cathode required a low cell voltage of 1.54 V at 10 mA cm−2. This work represents a significant advance in interface construction of transition-metal phosphide/sulfide for long-term water splitting. [Display omitted] • A novel CoMoP/Ni 3 S 2 core-shell nanowires successfully constructed. • The freestanding core-shell demonstrated amazing HER and OER activities. • CoMoP/Ni 3 S 2 required 96.8 mV (at η 10) for HER and 270 mV (at η 50) for OER process. • The catalyst based electrolyzer requires only 1.54 V at 10 mA cm−2. [ABSTRACT FROM AUTHOR]

In this study, quaternized poly (arylene ether sulfone) (QNPAES) was synthesized using conventional nucleophilic aromatic polycondensation. We then developed a blended membrane composed of sulfonated poly (ether ether ketone) (SPEEK) using facile solution casting. A series of mixed hybrid membranes of SPEEK/QNPAES were prepared by varying the wt% of QNPAES mixed with SPEEK. The results showed that an appropriate amount of QNPAES (i.e., 6 wt%) could significantly improve the mechanical strength, proton conductivity and physicochemical properties of a prepared mixed membrane, as well as the proton exchange membrane fuel cell (PEMFC) performance and durability at relative humidity (RH) of 20%. Specifically, a SPEEK/QNPAES at 6 wt% provides a current output, power output and endurance of 0.431 A cm−2, 0.15 W cm−2 and over 900 h, respectively, at an RH of 20% and 60 °C. These results can be attributed to acid-base ionic crosslinking, which offers effective interfacial compatibility between SPEEK and QNPAES. A PEMFC with SPEEK/QNPAES membranes when used at 20% RH achieved significantly advanced performance and ultra-high, long-term durability compared with those of PEMFCs with bare SPEEK, suggesting that SPEEK/QNPAES membranes can be used as polymer electrolyte membranes. Proton transport of SPEEK/QNPAES acid-base blended membranes for PEFC performance and ultra-high, long-term durability over 900 h. [Display omitted] • QNPAES was synthesized using conventional nucleophilic aromatic polycondensation. • The SPEEK/QNPAES (6 wt%) demonstrated significantly improved proton conductivity. • Acid-base crosslinking offers effective compatibility between SPEEK/QNPAES. • The SPEEK/QNPAES provides maximum current output and power density. • The SPEEK/QNPAES exhibits long-term durability under 20% RH for 900 h. [ABSTRACT FROM AUTHOR]

Transition bimetallic compounds are exploited as high-capacity electrode materials for supercapacitors due to their abundant electroactive sites and electrical conductivity. However, it remains grand challenge to construct supercapacitor devices that deliver high energy density. Here, we report an attractive one-stone-two-birds strategy to develop metal organic frameworks (MOFs) derived cathodes and anodes consisting of zinc cobalt telluride integrated nitrogen doped carbon (ZnCoTe–N–C) and zinc cobalt nanoparticles encased nitrogen doped carbon nanotubes (ZnCo-NPs-N-CNTs), respectively. Particularly, ZnCoTe–N–C cathode exhibited high specific capacity of 192.77 mA h g−1, which was further improved by the presence of hierarchical molybdenum disulfides (MoS 2) nanosheets. Increased electrochemical active sites provided by MoS 2 nanosheets energizes both the capacity and stability of the electrode. Consequently, the ZnCoTe–N–C/MoS 2 electrodes showed a higher specific capacity of 342.55 mA h g−1 as well as excellent long-term stability. Besides, the ZnCo-NPs-N-CNTs demonstrated an initial capacity of 207.22 mA h g−1 and retained a high specific capacity even after 50 A g−1. The excellent electrochemical activity of the electrodes is attributed to the incorporation of redox rich bimetallic components and nitrogen rich carbon directly grown on the current collector, which reduces the dead volume and avoids volume expansion during charge discharge process. Finally, a hybrid asymmetric supercapacitor (HASCs) assembled using ZnCoTe–N–C/MoS 2 and ZnCo-NPs-N-CNTs delivered a high specific energy density and power density maintaining 93.6% of its capacitance after 20,000 cycles. This study expands a way to construct a hybrid supercapacitor with well-designed structure and superior performance for clean energy storage technologies utilizing minimum resources. [Display omitted] • ZnCo-MOF is utilized to obtain cathode and anode for hybrid supercapacitor. • Cathode: ZnCoTe–N–C/MoS 2 exhibited high specific capacity of 342.55 mA h g−1. • Anode: ZnCo-NPs-N-CNTs maintains excellent rate capability and stability. • HASCs delivered incredible specific energy density 108.41 W h kg−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • A ternary ZnMgAl-LDH@Fe 2 O 3 /3DHPCNF were successfully prepared. • The electrode showed excellent electrochemical activity as both anode and cathode. • The structural and electrochemical effect of Zn has been studied in detail. • The optimized ZnMgAl-LDH@Fe 2 O 3 /3DHPCNF has yielded capacity of 3437 mF cm−2. • The supercapacitor device delivered high energy density of 11.622 mW cm−3 at 9.999 mW cm−3. Nano confinement of Layered double hydroxide (LDHs) nanosheets and metal oxide is a compelling way to develop new functional materials with unique physiochemical features for various energy storage devices with enhanced performance. Herein, ternary zinc-magnesium-aluminum layered double hydroxide (ZMA-LDH) nanosheets and hematite (α-Fe 2 O 3) nanorods are confined in a hetero-interfacial orientation on electrospun three-dimensional hollow and porous carbon nanofibers (3DHPCNF) by a subsequent hydrothermal process, resulting in the formation of a multi-dimensional nanoarchitecture. Such a structure can incorporate a conductive matrix and eliminate the need of current collectors, thereby minimizing the dead mass in electrochemical energy storage materials. The amount of Zn significantly determines the structural, morphological, and electrochemical properties of ZMA-LDH nanostructures. ZMA-LDH@Fe 2 O 3 /3DHPCNF was used as a free-standing electrode material for supercapacitors and endowed high capacitive behavior at both positive and negative working potentials. With the well-arranged 1D-3D hollow and porous interconnection, increased terrestrial surface area, and superior electrical conductivity, the hierarchical composite electrode offers a high areal capacitance of 3437F cm−2 at 1 mA cm−2 and ultrahigh cyclic stability. This fascinating electrochemical performance is attributed to the synergistic effect of 1D/2D/3D hollow and porous nanostructures, bimetallic compositions, top-to-bottom utilization of electrode materials, and unique combinations of surface interfacial diffusion and faradaic reduction governed by carbon and LDH/Fe 2 O 3 , respectively. Furthermore, a flexible all solid-state ZMA-LDH@Fe 2 O 3 /3DHPCNF symmetric supercapacitor exhibited a high areal energy density at a high power density along with excellent cyclability. This result suggests new prospects to design highly efficient multi material based electrodes for energy storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel MOF derived Co-Al-LDH@Fe 2 O 3 /3DPCNF adsorbents was synthesized. • The hybrid nanocomposites showed excellent adsorption capacities on Cr(VI) and Pb(II). • The adsorption isotherm, kinetics, thermodynamics, and mechanism were discussed in detail. • The composite can be easily recovered by magnet after adsorption process. Metal organic framework (MOF) derived layered double hydroxide (LDHs) are not properly probed in the field of the heavy metal ions adsorption from its aqueous solution, although they demonstrated a high possibility in adsorption. In this report, a Co-Al layered double hydroxide loaded with hematite (α-Fe 2 O 3)@3D porous carbon nanofiber (Co-Al-LDH@Fe 2 O 3 /3DPCNF) was synthesized by a sequential hydrothermal process. The Co-Al LDH was derived from a Co-metal organic framework. FE-SEM, TEM, FTIR, XPS, and BET characterizations and Cr(VI) and Pb(II) adsorption capacities of the composites were investigated in detail. The super hydrophilic Co-Al-LDH@Fe 2 O 3 /3DPCNF exhibited superfast removal efficiencies for Cr(VI) and Pb(II) with maximum adsorption capacities of 400.40 mg g−1 and 426.76 mg g−1, respectively. Precipitation, surface complexation, isomorphic substitution, and electron transfer were considered to be the main adsorption mechanisms. Adsorption isotherms were well fitted using the Sips model, and the adsorption thermodynamics demonstrated that the adsorption process is endothermic and spontaneous. The Co-Al-LDH@Fe 2 O 3 /3DPCNF maintained excellent adsorption capacity after ten cycles. The present study provides a new pathway to significantly improve the adsorption performance and stability of LDHs with easy separation from water body. [ABSTRACT FROM AUTHOR]

We report a polyaniline-wrapped, manganese-doped titanium oxide (PANi/Mn-TiO2) nanoparticle composite for supercapacitor electrode and photocatalytic degradation. The PANi/Mn-TiO2 nanoparticles were synthesized using a solvothermal process, followed by oxidative polymerization of aniline. The structural properties of studied materials were confirmed by XRD, FTIR, HRTEM, FESEM, and UV visible spectroscopy. The as-prepared PANi/Mn-TiO2 nanoparticles revealed admirable electrochemical performance with a specific capacitance of 635.87 F g−1 at a current density of 1 A g−1 with a notable life cycle retention of 91% after 5000 charge/discharge cycles. Furthermore, the asymmetric cell with PANi/Mn-TiO2 as a positive electrode exhibited energy density of 18.66 W h kg−1 with excellent stability. Moreover, the PANi/Mn-TiO2 had promising photocatalytic activity for methylene blue degradation. The improved performance of PANi/Mn-TiO2 nanoparticles is attributed to the well-built synergetic effect of components that lead to significant reduction of band gap energy and charge transfer resistance, as revealed by UV visible spectroscopy and electrochemical impedance spectroscopy. [ABSTRACT FROM AUTHOR]

Environmental remedies, including adsorption-based water purification, are now being asked to meet the requirement for a low-carbon circular economy requiring low energy and low material consumption. In this regard, we tested the possibility of regenerating adsorbents via cold plasma (CP) treatment for less use of adsorbents and no washing solution. In the adsorption of methylene blue (MB) using carbonized rice husk (CRH) and five successive regeneration cycles by CP treatment, the removal efficiencies were maintained at a moderate level (∼70% of the initial performance), unlike five consecutive adsorption without CP treatment (∼9–13% of the initial performance). The regeneration of CRH by CP treatment was also double-checked by the FESEM, EDS, BET, FTIR, XPS, and surface zeta potential measurements. The successfully recovered adsorption capability is related to the remediation of adsorption sites. It is also worth noting that the required power consumption for recycling by CP treatment was about 6.4 times lower than carbonizing new rice husks. This work provides insights into recovering adsorbents using CP without rigorous, costly, and energy-intensive processes. [Display omitted] • Carbonized rice husk (CRH) was used for adsorption-based removal of dye molecules. • The adsorption kinetics was governed by the pseudo-second-order model. • Cold plasma (CP) treatment successfully regenerated the dye-adsorbed CRH. • CP treatment was workable for the five consecutive adsorption tests of the used CRH. • The regeneration mechanism was discussed in detail based on thorough analyses. [ABSTRACT FROM AUTHOR]