Nickel sulfide is regarded as a material with tremendous potential for energy storage and conversion applications. However, it exists in a variety of stable compositions and obtaining a pure phase is ...a challenge. This study demonstrates a potentially scalable, solvent free and phase selective synthesis of uncapped α-NiS, β-NiS and α-β-NiS composites using nickel alkyl (ethyl, octyl) xanthate precursors. Phase transformation and morphology were observed by powder-X-ray diffraction (p-XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The comparative efficiency of the synthesized samples was investigated for energy storage and generation applications, in which superior performance was observed for the NiS synthesized from the short chain xanthate complex. A high specific capacitance of 1,940 F/g, 2,150 F/g and 2,250 F/g was observed at 2 mV/s for bare α-NiS, β-NiS and α-β-NiS composite respectively. At high current density of 1 A/g, α-NiS showed the highest capacitance of 1,287 F/g, with 100% of Coulombic efficiency and 79% of capacitance retention. In the case of the oxygen evolution reaction (OER), β-NiS showed an overpotential of 139 mV at a current density of 10 mA/cm
, with a Tafel slope of only 32 mV/dec, showing a fast and efficient process. It was observed that the increase in carbon chain of the synthesized self-capped nickel sulfide nanoparticles decreased the overall efficiency, both for energy storage and energy generation applications.
•Higher cereal productivity can be achieved with lower environmental footprint through conservation agriculture.•Wheat productivity and profitability can be increased by zero-tillage and early ...sowing.•Kharif maize appears to be a suitable and profitable alternative to rice in northwest India.•Productivity and resource efficiency of transplanted rice can be improved by BMPs.•Directly sown rice has potential to save water, energy and global warming potential compared to transplanted rice.
In the most productive area of the Indo-Gangetic Plains in Northwest India where high yields of rice and wheat are commonplace, a medium-term cropping system trial was conducted in Haryana State. The goal of the study was to identify integrated management options for further improving productivity and profitability while rationalizing resource use and reducing environmental externalities (i.e., “sustainable intensification”, SI) by drawing on the principles of diversification, precision management, and conservation agriculture. Four scenarios were evaluated: Scenario 1 – “business-as-usual” conventional puddled transplanted rice (PTR) followed by (fb) conventional-till wheat; Scenario 2 – reduced tillage with opportunistic diversification and precision resource management PTR fb zero-till (ZT) wheat fb ZT mungbean; Scenario 3 – ZT for all crops with opportunistic diversification and precision resource management ZT direct-seeded rice (ZT-DSR) fb ZT wheat fb ZT mungbean; and Scenario 4 – ZT for all crops with strategic diversification and precision resource management ZT maize fb ZT wheat fb ZT mungbean. Results of this five-year study strongly suggest that, compared with business-as-usual practices, SI strategies that incorporate multi-objective yield, economic, and environmental criteria can be more productive when used in these production environments. For Scenarios 2, 3, and 4, system-level increases in productivity (10–17%) and profitability (24–50%) were observed while using less irrigation water (15–71% reduction) and energy (17–47% reduction), leading to 15–30% lower global warming potential (GWP), with the ranges reflecting the implications of specific innovations. Scenario 3, where early wheat sowing was combined with ZT along with no puddling during the rice phase, resulted in a 13% gain in wheat yield compared with Scenario 2. A similar gain in wheat yield was observed in Scenario 4 vis-à-vis Scenario 2. Compared to Scenario 1, wheat yields in Scenarios 3 and 4 were 15–17% higher, whereas, in Scenario 2, yield was either similar in normal years or higher in warmer years. During the rainy (kharif) season, ZT-DSR provided yields similar to or higher than those of PTR in the first three years and lower (11–30%) in Years 4 and 5, a result that provides a note of caution for interpreting technology performance through short-term trials or simply averaging results over several years. The resource use and economic and environmental advantages of DSR were more stable through time, including reductions in irrigation water (22–40%), production cost (11–17%), energy inputs (13–34%), and total GWP (14–32%). The integration of “best practices” in PTR in Scenario 2 resulted in reductions of 24% in irrigation water and 21% in GWP, with a positive impact on yield (0.9t/ha) and profitability compared to conventional PTR, demonstrating the power of simple management changes to generate improved SI outcomes. When ZT maize was used as a diversification option instead of rice in Scenario 4, reductions in resource use jumped to 82–89% for irrigation water and 49–66% for energy inputs, with 13–40% lower GWP, similar or higher rice equivalent yield, and higher profitability (27–73%) in comparison to the rice-based scenarios. Despite these advantages, maize value chains are not robust in this part of India and public procurement is absent. Results do demonstrate that transformative opportunities exist to break the cycle of stagnating yields and inefficient resource use in the most productive cereal-based cropping systems of South Asia. However, these SI entry points need to be placed in the context of the major drivers of change in the region, including market conditions, risks, and declining labor availability, and matching with the needs and interests of different types of farmers.
In recent times, tremendous efforts have been devoted to the efficient and cost-effective advancements of electrochemically active metal oxide nanomaterials. Here, we have synthesized a facile ...nanomaterial of ZnO@PdO/Pd by employing extracted fuel from
E. cognata
leaves following a hydrothermal route. The phyto-fueled ZnO@PdO/Pd nanomaterial was fabricated into a supercapacitor electrode and was scrutinized by galvanostatic charge-discharge, electrochemical impedance spectroscopy and cyclic voltammetry to evaluate its energy storage potential, and transport of electrons and conductivity. Substantial specific capacitance
i.e.
, 178 F g
−1
was obtained in the current study in aKOH electrolyte solution. A specific energy density of 3.7 W h Kg
−1
was measured using the charge-discharge data. A high power density of 3718 W Kg
−1
was observed for the ZnO@PdO/Pd electrode. Furthermore, the observed low internal resistance of 0.4 Ω suggested effective electron- and ion diffusion. Thus, the superb electrochemical behavior of the ZnO@PdO/Pd nanocomposite was exposed, as verified by the significant redox behavior shown by cyclic voltammetry and galvanostatic charge-discharge.
In recent times, tremendous efforts have been devoted to the efficient and cost-effective advancements of electrochemically active metal oxide nanomaterials.
Currently, the sustainable fabrication of supercapacitors with enhanced properties is one of the significant research hotspots. Nevertheless, the performances of energy storage devices critically ...depend on their electrode materials. Accordingly, herein, we report the synthesis of a ZnO–Co3O4 nanocomposite using organic compounds of E. cognata, which was obtained via sol–gel synthesis. According to the synthesis strategy, the precursor solution was treated with a plant organic complex, and the consequent transformation to ZnO–Co3O4 was achieved via annealing a metal phyto-organic framework-derived complex in air. Furthermore, we tailored the surface chemistry of ZnO–Co3O4 using organic molecules of E. cognata. The present study successfully synthesized ZnO–Co3O4 nanocomposite with a particle size of 20 nm, which was subsequently investigated as an electrode material for supercapacitors. Consequently, it was revealed that the nano-features and phyto-organic functional groups provided abundant active sites for charge storage with a specific capacitance of 165 F g−1, as calculated by the cyclic voltammetry. The phyto-functionalized nanocomposite exhibited an energy density of 4.1 W h kg−1 and a power density of 7.5 kW kg−1, which were calculated using charge discharge data. Therefore, all the findings effectively demonstrate the potential of the functionalized ZnO–Co3O4 nanocomposite as an effective electrode material for application as a supercapacitor on a practical scale.
Transitional metal oxide nanomaterials are considered to be potential electrode materials for supercapacitors. Therefore, in the past few decades, huge efforts have been devoted towards the ...sustainable synthesis of metal oxide nanomaterials. Herein, we report a synergistic approach to synthesize spherical-shaped CoMoO4 electrode materials using an inorganic–organic template via the hydrothermal route. As per the synthesis strategy, the precursor solution was reacted with the organic compounds of E. cognata to tailor the surface chemistry and morphology of CoMoO4 by organic species. The modified CoMoO4 nanomaterials revealed a particle size of 23 nm by X-ray diffraction. Furthermore, the synthesized material was scrutinized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy and energy dispersive spectroscopy. The optical band gap energy of 3.6 eV was calculated by a Tauc plot. Gas chromatography-mass spectrometry identified cyclobutanol (C4H8O) and octodrine (C8H19N) as the major stabilizing agents of the CoMoO4 nanomaterial. Finally, it was revealed that the bioorganic framework-derived CoMoO4 electrode exhibited a capacitance of 294 F g−1 by cyclic voltammetry with a maximum energy density of 7.3 W h kg−1 and power density of 7227.525 W kg−1. Consequently, the nanofeatures and organic compounds of E. cognata were found to enhance the electrochemical behaviour of the CoMoO4-fabricated electrode towards supercapacitor applications.
The demand for economic and efficient electrode for energy storage devices has been increased with the rapid advancements in the sustainable synthesis of active material. Herein, bioactive compounds ...as fuel for the synthesis of electrode material (Co3O4 NPs), were investigated. Functionalization of Co3O4 NPs via organic extract of Euphorbia cognata Boiss have not only revealed the rapid and efficient growth of active materials but also ensured an effective interaction between the fabricated electrode and electrolyte solution for charge storage reactions. The synthesized Co3O4 NPs were scrutinized for its optical, structural, compositional and chemical properties and then investigated by galvanostatic charge discharge, cyclicvoltammetry for determination of its energy storage potential. The fabricated electrode was tested at range of scan rates and current densities to evaluate its charge storage potential at different scan rates and current densities. The phytofunctionalized Co3O4 NPs offered a large accessible active sites for charge storage with capacitance of 103 Fg-1, a maximum energy density of 1.9 Whkg−1, and higher power density of 4.7 KWkg−1. Thus, we have demonstrated the sustainable fabrication of electrode for energy storage applications.
•E. cognata Co3O4 nano electrode of supercapacitor.•The specfic capacitance of 103 Fg−1.•Biomimetic Co3O4 for energy storage.
The development of cost-effective, functional materials that can be efficiently used for sustainable energy generation is highly desirable. Herein, a new molecular precursor of bismuth ...(tris(selenobenzoato)bismuth(III), Bi(SeOCPh)3), has been used to prepare selectively Bi or Bi2Se3 nanosheets via a colloidal route by the judicious control of the reaction parameters. The Bi formation mechanism was investigated, and it was observed that the trioctylphosphine (TOP) plays a crucial role in the formation of Bi. Employing the vapor deposition method resulted in the formation of exclusively Bi2Se3 films at different temperatures. The synthesized nanomaterials and films were characterized by p-XRD, TEM, Raman, SEM, EDX, AFM, XPS, and UV–vis spectroscopy. A minimum sheet thickness of 3.6 nm (i.e., a thickness of 8–9 layers) was observed for bismuth, whereas a thickness of 4 nm (i.e., a thickness of 4 layers) was observed for Bi2Se3 nanosheets. XPS showed surface oxidation of both materials and indicated an uncapped surface of Bi, whereas Bi2Se3 had a capping layer of oleylamine, resulting in reduced surface oxidation. The potential of Bi and Bi2Se3 nanosheets was tested for overall water-splitting application. The OER and HER catalytic performances of Bi2Se3 indicate overpotentials of 385 mV at 10 mA cm–2 and 220 mV, with Tafel slopes of 122 and 178 mV dec–1, respectively. In comparison, Bi showed a much lower OER activity (506 mV at 10 mA cm–2) but a slightly better HER (214 mV at 10 mA cm–2) performance. Similarly, Bi2Se3 nanosheets were observed to exhibit cathodic photocurrent in photoelectrocatalytic activity, which indicated their p-type behavior.
Mixed metal sulfides are increasingly being investigated because of their prospective applications for electrochemical energy storage and conversion. Their high electronic conductivity and high ...density of redox sites result in significant improvement of their electrochemical properties. Herein, the composition-dependent supercapacitive and water splitting performance of a series of Ni(1−x)CuxCo2S4 (0.2 ≤ x ≤ 0.8) solid solutions prepared via solvent-less pyrolysis of a mixture of respective metal ethyl xanthate precursors is reported. The use of xanthate precursors resulted in the formation of surface clean nanomaterials at low-temperature. Their structural, compositional, and morphological features were examined by p-XRD, SEM, and EDX analyses. Both supercapacitive and electrocatalytic (HER, OER) properties of the synthesized materials significantly vary with composition (Ni/Cu molar content). However, the optimal composition depends on the application. The highest specific capacitance of 770 F g−1 at a current density of 1 A g−1 was achieved for Ni0.6Cu0.4Co2S4 (NCCS-2). This electrode exhibits capacitance retention (CR) of 67% at 30 A g−1, which is higher than that observed for pristine NiCo2S4 (838 F g−1 at 1 A g−1, 47% CR at 30 A g−1). On the contrary, Ni0.4Cu0.6Co2S4 (NCCS-3) exhibits the lowest overpotential of 124 mV to deliver a current density of 10 mA cm−2. Finally, the best OER activity with an overpotential of 268 mV at 10 mA cm−2 was displayed by Ni0.8Cu0.2Co2S4 (NCCS-1). The prepared electrodes exhibit high stability, as well as durability.
Eco-friendly and cost-effective catalysts with multiple active sites, large surface area, high stability and catalytic activity are highly desired for efficient water splitting as a sustainable green ...energy source. Within this line, a facile synthetic approach based on solventless thermolysis was employed for the simple and tunable synthesis of Ni
Mg
Fe
O
(0 ≤ x ≤ 1) nanosheets. The characterization of nanosheets (via p-XRD, EDX, SEM, TEM, HRTEM, and SAED) revealed that the pristine ferrites (NiFe
O
and MgFe
O
), and their solid solutions maintain the same cubic symmetry throughout the composition regulation. Elucidation of the electrochemical performance of the nanoferrite solid solutions showed that by tuning the local chemical environment of Ni in NiFe
O
via Mg substitution, the intrinsic catalytic activity was enhanced. Evidently, the optimized Ni
Mg
Fe
O
catalyst showed drastically enhanced HER activity with a much lower overpotential of 121 mV compared to the pristine NiFe
O
catalyst. Moreover, Ni
Mg
Fe
O
catalyst exhibited the best OER performance with a low overpotential of 284 mV at 10 mA/cm
in 1 M KOH. This enhanced electrocatalytic activity could be due to improved electronic conductivity caused by the partial substitution of Ni
by Mg
in the NiFe
O
matrix as well as the synergistic effect in the Mg-substituted NiFe
O
. Our results suggest a feasible route for developing earth-abundant metal oxide-based electrocatalysts for future water electrolysis applications.
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