Facile Chemical Method Research Articles

Hydrophilic Ni(OH)2@CoB nano-chains with shell-core structure as an efficient catalyst for oxygen evolution reaction

Enormously active and cost-effective electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are the critical components to produce hydrogen via water splitting using the electricity produced from renewable energy sources. Herein, inspired by the highly electric conductivity of CoB, shell-core structured Ni(OH)2@CoB nano-chains are synthesized as highly active OER catalyst with the assistance of the magnetic field. In the shell-core structured Ni(OH)2@CoB nano-chains, Ni(OH)2 nanoflakes were directly grown onto CoB nano-chains via a facile and wet chemical method. Ni(OH)2 in nanoflake form can provide more available active sites on the surface for electrochemical reaction that is evidenced by high BET surface area (648.9 m2 g−1). At the current density of 10 mA cm−2, the overpotentials of OER occurred on Ni(OH)2@CoB is 320 mV. The obtained Ni(OH)2@CoB also shows very good OER durability without any observable decline for 12 h. The high OER catalytic performance combined with its low-cost makes the Ni(OH)2@CoB nano-chains promising OER catalyst for water splitting in alkaline media.

Electrocatalytic reduction of CO2 to CO over iron phthalocyanine-modified graphene nanocomposites

The non-precious materials with iron-pyrrolic nitrogen-carbon (Fe–N–C) moiety have attracted an increasing attention on the CO2 reduction reaction (CO2RR). However, the influence of iron valence state and environmental synergy is not still clear. Here, iron phthalocyanine (FePc) molecule with an intrinsic Fe–N4–C moiety is enough dispersed on graphene as the single-atom iron catalyst through a facile chemical method. The FePc-graphene composites with different FePc content and iron valence state are synthesized to investigate their catalysis for the CO2RR to CO. The onset overpotential of 190 mV and Faradaic efficiency of >90% may be achieved in the optimal composites. Experimental and calculational results prove the positive role and synergy of Fe(II)Pc with Fe(III)Pc and graphene. The formation of ∗COOH intermediate is confirmed to be the rate-limiting step. The theoretical calculation reveals that Fe(II)Pc should have higher activity than Fe(III)Pc, and Fe(II)Pc/FePc(III) dimer may be better than individual one. This work clearly exhibits the effect of Fe2+/3+- pyrrolic N4–C on the CO2RR.

Intercalation-Induced Disintegrated Layer-By-Layer Growth of Ultrathin Ternary Mo(Te1-xSx)2 Plates.

Nanometer-thick transition-metal dichalcogenides (TMDs) have attracted increasing research interest because of their exotic physical properties, but their high-yield and large-scale synthesis remains a challenge for their practical device applications. In this study, we realize the high-yield synthesis of nanometer-thick single-crystalline Mo(Te1-xSx)2 plates by a facile chemical vapor deposition method. Adding S powders in the precursors can result in the products varying from well-faceted MoTe2 hexagonal plates to irregular Mo(Te1-xSx)2 plates with randomly stacked nanometer-thick layer steps. Moreover, their lateral dimension increases from several μm for binary MoTe2 to several tens of μm for ternary Mo(Te1-xSx)2. More interestingly, such irregular Mo(Te1-xSx)2 plates can form few layers by ultrasonic exfoliation. Our detailed electron microscopy analyses show that three kinds of S forms influence the ternary growth. In particular, elemental S8 intercalations play an important role in the growth and exfoliation of ultrathin Mo(Te1-xSx)2 plates. This study enriches the fundamental understanding of zero-valent intercalation in TMDs and provides a new insight into secure high-yield nanometer-thick TMDs, which is critical for practical applications.

Bimetallic PtCu-decorated reduced graphene oxide (RGO)-TiO2 nanocomposite for efficient oxygen reduction reaction

To exploit the full advantages of electrocatalysts for fuel cell reactions, a promising support is essential to disperse electrocatalytically active metal nanoparticles. Here, at first a graphene oxide-titanium dioxide composite support (GO-TiO2) is fabricated by a sol–gel method. Later, a facile chemical reduction method is demonstrated to simultaneously reduce Pt4+, Cu2+ and GO-TiO2 to form bimetallic PtCu nanoparticles (15 wt% Pt + 5 wt% Cu) on a reduced graphene oxide-titanium dioxide (RGO-TiO2) composite support. A combined action of ethylene glycol and ascorbic acid play a positive role in attaining well dispersed PtCu with a size of 7 nm particles on RGO-TiO2 sheets. The resulting PtCu/RGO-TiO2 nanocomposite exhibits superior electrode-area normalized ORR limiting current density (6.14 mA/cm2-geo) when compared to commercial Pt/C (3.61 mA/cm2-geo) and in-house synthesized PtCu/RGO (4.68 mA/cm2-geo) and Pt/RGO (3.95 mA/cm2-geo) catalysts. The synthesized catalysts are characterized for structural, morphological and surface elemental features by using a combination of diffraction, spectroscopy and electron microscopy techniques. The positive role played by PtCu and RGO-TiO2 composite support assists the improved ORR activity. The versatile synthesis methodology presented here is convenient to fabricate other similar electrocatalytic nanostructures for fuel cell reactions.

Facile synthesis of hierarchical flower-like NiMoO4-CoMoO4 nanosheet arrays on nickel foam as an efficient electrode for high rate hybrid supercapacitors

• Flower-like NiMoO 4 CoMoO 4 nanosheet arrays (NSAs) are grown on Ni foam using facile chemical bath deposition route. • NiMoO 4 CoMoO 4 NSAs used as a battery-type material for supercapacitor applications. • Unique NiMoO 4 CoMoO 4 NSAs are favourable for rapid ion and electron transfer. • NiMoO 4 CoMoO 4 NSAs electrode exhibit the superior electrochemical properties than bare NiMoO 4 and CoMoO 4 . • Hybrid supercapacitor (NiMoO 4 CoMoO 4 NSAs//G-ink) delivers the high specific energy, specific power and long-term cycling stability. Binder-free hierarchical flower-like NiMoO 4 CoMoO 4 nanosheet arrays (NSAs) have been successfully grown on nickel (Ni) foam surface via a facile one-step chemical bath deposition method followed by calcination treatment. The as-prepared NiMoO 4 CoMoO 4 NSAs electrode material has been effectively used as a battery-type material for supercapacitor applications. Surface morphological and structural studies reveal that the as-fabricated NiMoO 4 CoMoO 4 electrode exhibits a flower-like heterostructures constructed with interconnected nanosheet arrays. In a three-electrode system, the potential plateaus from the cyclic voltammetry and galvanostatic charge–discharge measurements indicate that the obtained NiMoO 4 CoMoO 4 NSAs electrode exhibits Faradic battery-type redox behaviour, which is different form the profiles of carbon-based materials. As a battery-type material, NiMoO 4 CoMoO 4 NSAs electrode delivers a remarkable specific capacity of (~236.86 mA h g −1 at 2 A g −1 ), excellent rate capability (~92.44% retains even at 10 A g −1 ), and superior cycling stability (~97.19% at 6 A g −1 over 5000 cycles), which are much higher than those of the bare NiMoO 4 and CoMoO 4 electrodes. The superior electrochemical properties of the NiMoO 4 CoMoO 4 composite material are due to the synergetic effect from CoMoO 4 and NiMoO 4 and to the fact that the hierarchical nanosheet arrays provide abundant electroactive sites for rapid redox reactions. Additionally, hybrid supercapacitor (HSC) has been assembled using NiMoO 4 CoMoO 4 NSAs/Ni foam as the positive electrode and graphene-ink/Ni foam as the negative electrode. It is found to exhibit a good cycling stability and a high specific energy of 27.58 Wh kg −1 at a specific power of 636.05 W kg −1 . Thereby, these electrochemical performances suggest that the as-fabricated NiMoO 4 CoMoO 4 NSAs are promising candidates for electrodes in high-performance supercapacitors.

Enhanced selective adsorption ability of Cu2O nanoparticles for anionic dye by sulfur incorporation

Cu2O-based materials are potential adsorbents for the removal of anionic dyes pollutions. Herein, sulfur incorporation is designed to promote adsorption capacity of Cu2O. A series of sulfur-incorporated Cu2O nanomaterials are synthesized by a facile chemical reduction method. Sulfur incorporation favors the formation of small sized S-Cu2O particles in the range of 50–100 nm and their enhanced adsorption performances. The S-Cu2O particles show good adsorption activities for methyl orange solution (75–500 mg L−1) under pH 6–10 at room temperature. A superior adsorption capacity of 1485.24 mg g−1 for the removal of methyl orange is achieved on the S-Cu2O adsorbent. Adsorption behaviors of the S-Cu2O adsorbent fit well with Langmuir isotherm and pseudo-second-order kinetic model. Adsorption thermodynamic results indicate the exothermic and spontaneous adsorption process. Anionic dye can be adsorbed selectively on the S-Cu2O adsorbent and separated from cationic dyes. Density functional theory calculations prove a pronounced electron accumulation on sulfur sites, benefiting to the adsorption on S-Cu2O. A nonmetallic element incorporation for improving adsorption capacity of metal oxide adsorbents is provided as a promising strategy for other adsorbents.

Assessing the Photocatalytic Degradation of Fluoroquinolone Norfloxacin by Mn:ZnS Quantum Dots: Kinetic Study, Degradation Pathway and Influencing Factors.

Norfloxacin (NOFX), a broadly used fluoroquinolone antibiotic, has been a subject of great concern in the past few years due to its undesirable effect on human beings and aquatic ecosystems. In this study, novel Mn doped ZnS (Mn:ZnS) quantum dots (QDs) were prepared through a facile chemical precipitation method and used as photocatalysts for NOFX degradation. Prior to photodegradation experiments, morphological and optical parameters of the QDs were examined through transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, fluorescence spectroscopy, Brunauer–Emmett–Teller analysis, and differential thermal and thermogravimetric analyses. Mn:ZnS QDs exhibited excellent properties of photodegradation, not only under UV irradiation but also in sunlight, which induced NOFX to photodegrade. The utmost photodegradation efficiency was obtained under optimal conditions (25 mL of NOFX, 15 mg/L, pH 10, 60 min UV irradiation, 60 mgs QDs), adopting first order kinetics. In addition, hydroxyl radicals produced by the conduction band electrons were found to be the primary reason dominating the transformation of NOFX in basic conditions, while holes, oxygen atoms, as well as the doped metal (Mn) enhanced the degradation. The QDs showed excellent reusability and stability in four repeated cycles. Finally, four different pathways were predicted, derived from the identified intermediates, with piperazinyl ring transformation being the primary one. It is expected that the synthesized Mn:ZnS QDs could be utilized as efficient photocatalytic materials for energy conversion and ecological remediation.

Enhanced photoactivity of BiVO4/Ag/Ag2O Z-scheme photocatalyst for efficient environmental remediation under natural sunlight and low-cost LED illumination

Bismuth vanadate (BiVO4, BV) is a promising visible-light responsive semiconductor photocatalyst able to harvest sunlight energy for photoelectrochemical and photochemical applications such as pollutants degradation and oxygen evolution from water. However, the fast recombination of photogenerated electrons and holes and poor electron transport properties remain as the bottlenecks in the way of efficient utilization of BV for such applications. Aiming to address these issues, we prepared Ag/Ag2O-loaded BV particles using a facile chemical deposition method employing an alkaline solution of glycerol for partial reduction (formation of Ag0) and deposition of Ag+ (as Ag2O) from AgNO3 solution. The as-prepared BV/Ag/Ag2O Z-scheme photocatalysts were characterized by SEM, TEM, DRS, XPS, XRD, Raman spectroscopy and electrochemical measurements. XRD and XPS analysis confirmed the formation of heterojunction photocatalysts of the type BV/Ag/Ag2O that show light absorption in an extended region of the visible spectrum as compared to pure BV. Compared to pristine BV (kobs. = 0.016 min-1), the synergy between the components in the resulting BV/Ag/Ag2O photocatalysts led to a dramatic increase (around 28 times) in photoactivity (kobs. > 0.45 min-1), as measured by photodegradation of crystal violet (CV) and Rhodamine B (RhB) employing commercial low-cost blue LEDs or natural sunlight. The enhanced photoactivity is attributed to the extended absorption of visible light and improved adsorption of dyes by the composite photocatalysts and the formation of BV/Ag/Ag2O Z-scheme heterojunction characterized by better charge carriers’ separation. Such a photocatalytic system highlights: (i) high efficiency aspect (since the emission of LEDs matches the absorption edge of BV) (ii) practicality aspects (the use of low-power, DC-operated LED photoreactor and natural sunlight) and (iii) economical aspects (low-cost and longer life-time of LEDs).

Rational design and development of perovskite materials: Analysis of structural, optical, morphological and phase transition

Herein, we have introduced a facile chemical method for preparation of highly stable perovskite materials in large-scale for commercial purpose. A series of perovskite powders such as, MAPbI3, MAPbBr3, FAPbI3, FAPbBr3, CsPbI3 and CsPbBr3 were synthesized and studied the structural, optical, morphological properties. For the first time, temperature dependent phase transition of the perovskites investigated using EPR measurement from 298 K to 110 K. The powders form of the perovskite showed high stability in air at room temperature than the film forms due to its good crystal quality. This simple solution processing approach for production of large-scale perovskite powder open a new way for diverse applications of perovskite materials in future.

A novel nitrogen-deficient g-C3N4 photocatalyst fabricated via liquid phase reduction route and its high photocatalytic performance for hydrogen production and Cr(VI) reduction

A facile liquid phase chemical reduction method was developed to synthesize nitrogen-deficient graphitic carbon nitride (FH-g-C3N4) by application of the weak reducibility of formaldehyde in weak acidic solution. The nitrogen defects in g-C3N4 were confirmed by EA, EPR, XPS and EDS. The extra electrons in nitrogen-deficient sites can easily capture photogenerated holes and reduce the recombination of photogenerated electrons and holes. With appropriate amount of nitrogen defects, FH-g-C3N4 possesses the best photocatalytic activity which is 58% higher than that of H-g-C3N4 (without nitrogen defects) and P25 (TiO2) for Cr(VI) reduction, and its hydrogen production rate is twice of the H-g-C3N4. Compared with H-g-C3N4, FH-g-C3N4 has a stronger light absorption capacity, a more negative potential of conduction band, and a stronger reduction capacity. This work could provide significant information for the simple synthesis of nitrogen-deficient g-C3N4 photocatalyst with distinct reduction performance.

ZnFe2O4 nanoparticles imbedding in carbon prepared from leaching liquor of jarosite residue as anode material for lithium-ion batteries

ZnFe2O4 has attracted much attention as an anode material for lithium-ion batteries (LIBs) because of its high theoretical capacity. However, the fast capacity fading and poor rate performance severely hamper its practical application. To overcome these problems, herein, ZnFe2O4 nanoparticles uniformly embedded in carbon matrix (ZnFe2O4/C composite) were fabricated by a facile chemical co-precipitation method and subsequent calcination process with leaching liquor of jarosite residue, NaCO3, and ammonium citrate as raw materials. The prepared ZnFe2O4/C composite shows superior high-rate capability (with 731 mAh g−1 at 0.5 A g−1 and 321 mAh g−1 at 10 A g−1) and excellent cycling stability (with reversible capacity of 644 mAh g−1 after 1000 cycles at 2 A g−1). Cyclic voltammetry (CV) analysis reveals significant pseudocapacitive contributions during the discharge/charge processes of ZnFe2O4/C composite. This work provides a facile, efficient, and eco-friendly strategy for the preparation of high-performance transition metal oxides electrode materials for LIBs.

Investigation of the survival viability of cervical cancer cells (HeLa) under visible light induced photo-catalysis with facile synthesized WO3/ZnO nanocomposite.

The photo catalytic degradation, a proven chemical process used for the decontamination of organic/inorganic pollutants and microorganisms in water was implemented. In this work for the selective killing of cervical cancer cells (HeLa cells) by using nano-composite of ZnO (Zinc Oxcide), WO3 (tungsten oxide) and (n-WO3/ZnO) as a photo-catalyst under the irradiation of visible light. All the three nanostructured semiconducting materials (WO3, ZnO and n-WO3/ZnO) were synthesized by facile chemical precipitation method and their morphological and optical characterization studies were carried out to elucidate the observed enhancement in the photo-catalytic killing of HeLa cancer cells with n-WO3/ZnO as a photo-catalyst. After 60 min of photo-catalytic reaction with n-WO3/ZnO as a photo-catalyst, a survival viability of HeLa cancer cells as low as 15% was achieved (nearly 85% of killing), as compared to 65% of HeLa cancer cell survival viability (nearly 35% of killing) with individual use of WO3 and ZnO as photo-catalysts under the same irradiation and experimental conditions. This improved photo-catalytic killing of HeLa cancer cells using n-WO3/ZnO in the visible spectral region is attributed to the enhanced visible light absorption and reduced electron hole recombination, characteristically brought about in the n-WO3/ZnO composite material. As photo-catalytic killing of the cancer cells can be selective, localized and reasonably efficient, in principle, this method can be considered as a non-invasive targeted treatment option for killing any type of cancer cells. HeLa cells, in particular are the cervical cancer cell and the tumors in and around cervix, containing HeLa cells can be non-surgically accessed and photo-catalytically treated with appropriate photo-catalyst and light source.

Facile Ge/GR nanocubes synthesis and application for Sudan I photodegradation in water

In this work, highly uniform cubic germanium/husk-derived graphene nanocomposites (Ge/GR nanocubes) were synthesized via facile chemical methods. The structure and composition of the prepared Ge/GR nanocubes were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) etc., confirming a homogeneous distribution of Ge nanocubes (30–90 nm in size) on few-layered graphene nanosheets. Further investigations showed that the prepared novel Ge/GR nanocubes could combine both photocatalytical advantages of Ge nanocubes and graphene nanosheets for Sudan I purification with optimal removal efficiency of 98.1% in wide concentration range (0.25–4.0 mg/mL) at mild conditions. The prepared high active photocatalyst can be used for five consecutive runs. By using husk-derived graphite microcrystalline as the starting material of graphene, the cost of the Ge/GR nanocubes was obvious decreased, which fosters it a high active, low cost and durable candidate for azo dye removal in water.

Morphology-dependent highly active microcrystalline stannous oxalate photocatalysts with selectively exposed facets and low specific surface areas

To achieve high photocatalytic activity, the sizes of photocatalysts are usually reduced to nanoscales. However, nano-sized particles are difficult to be separated and recycled. In this paper, we successfully fabricate stannous oxalate microcrystals with selectively exposed facets and various morphologies (prismoids, tubes, rods and needles). The photocatalytic activities are comparative or even higher than that of commercial Degussa P25 nano titanium dioxide under both full spectrum light and ultra-violet irradiation, even though the stannous oxalate particles are in micrometer size. The exposure of {1¯01} polar facets could drive photogenerated charge separation, and thus accelerates photocatalysis. The photocatalytic activities of the optimized sample (fragmented prismoids) with specific surface areas about 1.18 m2/g are 2.49 and 2.67 times higher than that of the commercial Degussa P25 nano titanium dioxide (specific surface areas: 48.59 m2/g) under both full spectrum light and ultra-violet irradiation in methyl orange degradation, respectively. The micro/submicron-sized particles could be easily separated and recycled after waste water treatment, and catalysts can be synthesized with a large amount by a facile chemical precipitation method. Given these factors, micro/submicron sized stannous oxalate catalysts are expected to be a practical water cleaner.

WO3 thin films doped with Ru by facile chemical method with enhanced electrochromic properties for electrochromic window application

We report on WO3 thin films observed as platelets doped with Ruthenium (Ru) in various doping concentrations and synthesized using a facile surfactant free acid precipitation method. The synthesized thin films annealed at 500 °C for an hourrevealedchanges in morphology from plate-like structure to agglomerated nanoparticles after doping of Ru (0.05 and 0.1 wt%) in WO3. The resulting Ru doped WO3 thin films reveals two times improved performance in cycle stability and diffusion coefficient is increased by ten times as compared to synthesized pristine WO3thin films and these are discussed in terms of Ru doping effect in host matrix which induced compositional inhomogeneity, morphological change and disorder to show a fast switching response (coloration time; Tc = 2.28 s and beaching time; Tb = 1.98 s) and high reversibility 87% with coloration efficiency of 67 cm2/C and retention after 1000 cycles.

Epoxy-functionalized silane grafting enhances the cycling performances of Li1.2Ni0.13Co0.13Mn0.54O2 cathode materials

Epoxy-functionalized silane (KH560) modified Li1.2Ni0.13Co0.13Mn0.54O2 materials are prepared by a facile chemical grafting method for the first time. X-ray diffraction confirms that the crystal structure of Li1.2Ni0.13Co0.13Mn0.54O2 is not affected by the KH560 modification. Scanning electron microscopy and transmission electron microscopy results prove that KH560 is homogeneously grafted on the Li1.2Ni0.13Co0.13Mn0.54O2 surface with a thickness of 3–5 nm. The electrochemical tests reveal that the 1.0 wt% KH560 modified Li1.2Ni0.13Co0.13Mn0.54O2 cathodes retain 92.88% (1 C) and 98.24% (5 C) capacity retentions after 100 cycles, respectively, far higher than 83.09% (1 C) and 50.68% (5 C) of the pristine. The improved cycling performances are mainly attributed to the fact that the X-O-M bonds stabilize the surface oxygen and resist the parasitic reactions during cycling, which further can suppress the structure degradation and the impedance increase. This work provides a facile and effective modification method to optimize the interfacial structures of Li1.2Ni0.13Co0.13Mn0.54O2 and/or other cathode materials.

Nanocrystalline copper-chromium-layered double hydroxide with tunable interlayer anions for electrochemical capacitor application

Nanocrystalline copper-chromium-layered double hydroxide (CuCr-LDH) is prepared by facile chemical co-precipitation method. In order to investigate effects of interlayer anions on electrochemical properties of CuCr-LDH, the carbonate (CO32−) and nitrate (NO3-) anions are intercalated in to the layered CuCr-LDH. The obtained samples are characterized by powder X-ray diffraction (P-XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS)-elemental mapping analysis to study crystal structural, chemical bonding, surface textural as well as compositional properties. The layer-by-layer stacking of CuCr(OH)2 nanosheets that intercalated with CO32− and NO3− anions is evidenced by powder X-ray diffraction. The layered arrangement of CuCr(OH)2 nanosheets and homogeneous distribution of constituent elements over CuCr-LDH crystals are also evidenced by FESEM micrographs and EDS mapping analysis. The NO3− intercalated CuCr-LDH electrochemical capacitor electrode demonstrated a maximum specific capacitance of 843 Fg−1 with capacity retention up to 85 % after 1500 CV cycles, superior to CO32− intercalated CuCr-LDH with a specific capacitance of 522 Fg−1 and capacity retention up to 72 %. The NO3- intercalated CuCr-LDH demonstrated improved electrochemical capacitive activity as compared to CO32− intercalated CuCr-LDH.

Nanostructured black moly surfaces for solar thermal absorbers by wet chemical etching

Black Moly (MoO3) coatings obtained by a facile sustainable wet chemical etching method has been investigated to understand the effect of etchant time on the prepared coatings. The effect of the time of etching on the structural, morphological and optical properties of black moly coatings have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and UV–Vis spectroscopy. The XRD spectrum of the prepared coatings showed only peaks from the Molybdenum substrate indicating amorphous coatings. But when annealed at 500˚C, it showed crystallisation to MoO2. In this work, we developed a nanostructured coating, black moly, with a high solar absorptance of over 81%. These results suggest that black moly coatings made from refractory metal oxides can be used for solar thermal absorbers.

A novel chemical reduction/co-precipitation method to prepare sulfur functionalized reduced graphene oxide for lithium-sulfur batteries

The higher theoretical specific capacity with considerable cell potential, Lithium–Sulfur batteries (LSBs) are considered to be high-energy storage strategies near future. However, the practical realization of LSBs is being hindered owing to low cell capacity risen from poor electronic-conductivity of elemental sulfur. To enhance the electronic-conductivity and thus to improve the specific cell capacity, commonly conducting carbons such as reduced graphene oxide, carbon nanotubes etc. are used as additives in the electrodes. Here, we report a unique in-situ synthesis strategy to prepare a composite of sulfur-functionalized reduced graphene oxide (SFRGO) encapsulating monodisperse sulfur nanoparticles using a low-cost deep eutectic solvent (DES) derived from choline chloride and sodium thiosulfate. The DES serves as an effective reductant as well as dopant. Moreover, during formation of SFRGO, a major fraction of the DES degrades to elemental sulfur. The SFRGO composite has been applied as cathode material in LSBs. The cathode material delivered a maximum specific capacity of 1265 mA h g−1 during initial cycle and retains 903 mA h g−1 after 100 cycles, with a usual capacity decay rate 0.28% each cycle. This facile chemical reduction method is an alternative to the large-scale and cost-effective production of high-quality graphene for energy storage application.

Synthesis of Manganese Carbonate Templates with Different Morphologies and Their Application in Preparing Hollow MoS₂ Micro/Nanostructures for Photocatalysis.

Spherical manganese carbonate (MnCO³) templates were successfully prepared by a facile chemical precipitation method. The size of the as-prepared samples was changed by adjusting the ratio of MnSO₄·H2O and NaHCO₃ (1:1, 1:5, 1:10 and 1:15). More interestingly, when adding Na₂SO₄ to the reaction solution, the morphology of MnCO³ further evolved from an irregular spheroid to a cube. Next, spherical and cubic MnCO³ particles with the most uniform size were selected as precursor templates to synthesize intermediate compounds (MnCO³/MnS/MoS₂). Eventually, MoS₂ microspheres and microcubes with a hollow structure were obtained by removing the MnCO³ and MnS with acid pickling. The structure, morphology and elemental composition of the products were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS). The results of the photocatalytic experiments show that hollow MoS₂ prepared with an MnCO³ template exhibited excellent photocatalytic performance. Therefore, the application of a template method to prepare hollow structure materials is worthy of further study in the photocatalysis field.