Hierarchical Flower-like Structure Research Articles

The transformation of In2S3 film from flower-like to net-like structure by tunable microwave reaction for buffer layer in CuInS2/TiO2 solar cells

Two morphologies of In2S3 film were synthesized directly on FTO surface with microwave-assistant solution method. With reaction time/temperature/microwave power increasing, In2S3 film assembled by hierarchical flower-like structure (In2S3 flower) transformed into In2S3 film assembled by net-like structure (In2S3 net) with increased size and crystallinity. Compared to In2S3 flower, In2S3 net displayed stronger light-harvesting ability with higher charge separation, contributing to stronger photocurrent and lower charge transfer resistance. Based on the excellent photoelectrical properties, TiO2/In2S3/CuInS2/spiro-oMeTAD solar cells were fabricated with two In2S3 films as the buffer layers as compared to the device without In2S3, which displayed obviously higher photovoltaic parameters due to the decreased surface defects on TiO2 and the increased complementary absorption from In2S3. Furthermore, the device with In2S3 net presented higher short current density (Jsc) than that with In2S3 flower because the thicker In2S3 layer strengthened the contribution of complementary light-harvesting. However, it displayed lower open circuit voltage (Voc), which was attributed to the presence of defects on the surface of overgrown In2S3 for increased interfacial recombination.

Controllable Synthesis of Flower-like Hierarchical CuCo2S4 Nanostructure Arrays for High-Performance Hybrid Supercapacitors

Transition metal sulfides (TMSs) are considered as attractive materials in the areas of energy storage because of their unique redox properties, excellent electronic conductivity, as well as environmental friendliness. However, poor cyclic stability and limited electrochemical active sites hinder their further application. To address this issue, a flower-like hierarchical CuCo2S4 structure is constructed by a two-step hydrothermal method. In this nanostructure, CuCo2S4 grows outward to form a tightly bound hierarchical structure on the nickel foams (NFs). This oriented structure can provide more laminar gaps for electrolyte ion diffusion, exposing more reaction sites to increase the ion transport efficiency between the layers, reducing the ion transport resistance and improving the reaction kinetics. Thus, the CuCo2S4 electrode exhibits excellent energy storage performance, exhibiting a high specific capacity of 1415.6 F g−1 at 1 A g−1. After 10,000 cycles of 10 A g−1, it still has 91.9% of the initial performance. In addition, an asymmetrical supercapacitor (ASC) was constructed by choosing CuCo2S4 as the anode and RGO as the cathode, which has the maximum energy density (61.8 Wh Kg−1) at 812.1 W Kg−1 and significant cycling endurance (92.05% retention) at 10,000 turns. Briefly, the researchers successfully constructed an array of CuCo2S4 flower-like hierarchical nanostructures and confirmed their potential application in supercapacitors.

Boosting carrier separation and transport in CuGaO2 photocathodes by coupled effects of surface polarization and facet-junction

This study investigates the synergistic enhancement of carrier separation and transport in CuGaO2 photocathodes, achieved through the coupled effects of surface polarization and facet-junction engineering. Delafossite CuGaO2 microspheres, which exhibit a flower-like micro-nano hierarchical structure, are synthesized facilely through a one-pot hydrothermal process. These microspheres self-assemble from CuGaO2 nanosheets, driven by electrostatic forces among crystal facets. Morphology and size are systematically modulated by pH values, solvent composition, and reaction temperature. The CuGaO2 nanosheets, serving as fundamental building blocks, manifest notable surface polarization effects that facilitate the efficient transport of photo-generated carriers. The facet-junction formed between intersecting CuGaO2 nanosheets facilitates the collection of photo-generated electrons and holes on both sides of the interface, leading to spatial separation. Consequently, the CuGaO2 microspheres synergistically combine nanoscale surface polarization and microscale facet-junction effects, promoting the effective separation and rapid transport of electron-hole pairs generated under visible-light irradiation. The resulting simple bare photocathode, constructed using CuGaO2 microspheres, demonstrates a photocurrent density of 32 μA/cm2 at zero-bias, with a peak incident photon-to-current efficiency of 12.72 % at a 450 nm wavelength. Further optimization of the CuGaO2 photocathode yields a better photocurrent density of 138 μA/cm2 at 0.33 VRHE. These results underscore the significance of integrating nanoscale surface polarization effects with microscale facet-junction effects to achieve efficient separation and rapid transport of photo-generated carriers in photoelectrochemical cells.

Construction of CuO nanoparticles decorated In2O3 hierarchical structure for ultrasensitive and rapid trace detection formaldehyde at low temperature

The reasonable build of a highly efficient formaldehyde (HCHO) gas sensor with excellent performance and low concentration detection ability is an urgent requirement for environmental surveillance and human health protection. Herein, a HCHO sensing structure composed of nanoflower In2O3/CuO self-assembly was fabricated using a facile solvothermal route and characterized accordingly. The gas-sensing test data exhibited that the 3 wt% In2O3/CuO sensor presented remarkable HCHO detection performance with a large response value (Ra/Rg = 231.2, 100 ppm), which is around 4 times larger than that bare In2O3 sensor. The optimum operating temperature decreases from 260 ℃ to 140 ℃. Meanwhile, the 3 wt% In2O3/CuO sensor displayed shorter response and recovery times (9 and 17 s), outstanding selectivity, better moisture resistance, recyclability and strong stability. It is commendable that the sensor has achieved ppb level detection for HCHO. The brilliant sensing properties were ascribed to the formation of more active sites with the 3 wt% In2O3/CuO flower-like hierarchical structure. Besides, the gas-sensing improvement mechanism of the composite was explored in detail through the analysis of band structure, adsorption energy and total density of states. Thus, 3 wt% In2O3/CuO sensor open up a new perspective for detecting trace amounts of HCHO gas.

3D flower-like hollow MXene@MoS2 heterostructure for fast sodium storage

Constructing an anode with fast electron transport and high cycling stability is important but challenging for large-scale applications of sodium-ion batteries (SIB). In this study, hierarchical flower-like MXene structures were synthesized using poly (methyl methacrylate) (PMMA) microsphere as templates. Subsequently, a straightforward hydrothermal reaction was utilized to anchor small-sized MoS2 nanosheets. The resulting MXene@MoS2 heterostructure exhibits a distinctive three-dimensional (3D) porous hollow architecture. This structure effectively addresses challenges related to self-aggregation of MoS2 nanosheets and volume expansion of the electrode material during Na+ insertion/extraction processes. Furthermore, the robust hetero-interface supports fast and stable electron transfer, thereby enhancing electrochemical reaction kinetics. The prepared MXene@MoS2 electrode demonstrates the specific capacity of 682.1 mA h g−1 at 0.2 A/g and the reversible capacity of 494.4 mA h g−1 after 1000 cycles at 5 A/g. It is noteworthy that the full battery assembled with the composite material as the anode can still maintain the capacity of 456.2 mA h g−1 after 80 cycles at 0.5 A/g. This outstanding reversible capacity and sustained stability over numerous cycles highlights its potential for a wide range of applications.

Bovine Serum Albumin - Hydroxyapatite Nanoflowers as Potential Local Drug Delivery System of Ciprofloxacin.

Hybrid nanoflowers are structures consisting of organic (enzymes, proteins, nucleic acids) and inorganic components (mostly metal phosphates) with a flower-like hierarchical structure. Novel hybrid nanoflowers based on bovine serum albumin (BSA) and hydroxyapatite (HA) were obtained and characterized. Study on BSA-HA nanoflowers as potential drug delivery system is reported for the first time. Embedding ciprofloxacin in the structure of hybrid nanoflowers was confirmed by ATR-FTIR and thermogravimetric analysis. The inorganic phase of the nanoflowers was determined by X-ray diffraction. UV‒Vis spectroscopy was used to evaluate the release profiles of ciprofloxacin from nanoflowers in buffer solutions at pH 7.4 and 5. The agar disk diffusion method was used to study the antibacterial activity of the synthesized nanoflowers against Staphylococcus aureus and Pseudomonas aeruginosa. Bovine serum albumin - hydroxyapatite nanoflowers were obtained with diameters of ca. 1-2 µm. The kinetics of ciprofloxacin release from nanoflowers were described by the Korsmeyer-Peppas model. The antibacterial activity of the synthesized nanoflowers was demonstrated against S. aureus and P. aeruginosa, two main pathogens found in osteomyelitis. The formulated nanoflowers may act as an efficient local antibiotic delivery system. Due to the use of nonhazardous, biodegradable components and benign synthesis, hybrid nanoflowers are very promising drug delivery systems that could be applied in the treatment of skeletal system infections.

Photochromic hierarchical (NH4)xWO3 nanocrystals with bronze tunnel structure for energy-saving windows

Understanding photochromism is crucial for developing new ways to modulate the optical responses of materials. Here, we prepared ammonium tungsten bronze (NH4)xWO3, representing a significant advance in photochromism over the rarely chromogenic tungsten bronze. The high color difference, 12.89 and 30.49 for 10 s and 90 s exposure, respectively (AM 1.5G), was due to the large surface area created by the distinctive flower-like hierarchical structure, which exposed more photoactive sites, as well as to the highly efficient adsorption of the proton-coupled electron as a color center on the surface to trapped electrons. The elucidation of NH4+ protonation under the light field and/or chemical interactions with neighboring protonated species was revealed by the ion exchange sites in hexagonal, trigonal, and square sites, suggesting an essential surface structure-breaking behaviors of hydrogen bonds between NH4+ and tunneled WO3 frameworks. In particular, the created energy-saving window, based on hydrogen ammonium tungsten bronze (NH4)yWO3:nH/polyvinyl alcohol/polyvinylpyrrolidone coating, enabled a reduction of indoor air temperature by 6.3 °C in hot weather and reduced temperature difference between various indoor areas. The modification of the chemical environment of WO3 and the identification of the photochromism mechanism hold promise for the development of energy-saving windows using chromogenic nanomaterials.

Hierarchical flower-like MgAl layered double hydroxide microparticles as phosphate porter for its recovery from phosphate-contaminated water

Layered double hydroxide (LDH) represents an important class of adsorbents for phosphate (P) recovery from water, but the scale application remains challenged by the scarcity of LDH adsorbents with balanced adsorption capacity and settling performance. Herein we developed the three-dimensional MgxAl100-x-LDH microparticles (∼4 μm) with hierarchical flower-like structure and controlled compositions, which delivered fast P adsorption (equilibrium time < 5 min), large P adsorption capacities (108.8 mg g−1 by Mg60Al40-LDH) and better settling performances than the nanoscale LDH counterpart. The mechanistic study revealed that the robust adsorption performance of MgAl-LDH was attributed to the efficient anion exchange of P with the intercalated anions (Cl− and CO32−) in LDH. Owing to the exchangeability of intercalated P with the concentrated CO32− in aqueous solution, we demonstrated that almost all the P adsorbed in LDH could be recovered in 1.0 M Na2CO3 solution, and the cumulative P in solution could reach a concentration of 4.5 g/L after batches of recovery experiments. The Mg60Al40-LDH was further coupled with magnetic particles for P removal from natural lake water. The composite afforded high efficiencies in P removal and adsorbent separation from water (settling time: ∼10 min), but inadequate adsorption selectivity towards P especially in the presence of SO42− and dissolved organic matters. This work is expected to provide a new platform for both the efficient P recovery and adsorbent collection from wastewater.

Unveiling a cutting-edge bi-ligand nickel metal-organic framework as an electrode material for symmetric supercapacitors

Perylene diimide (PDI)-based MOFs feature a substantial specific capacitance, terrific cycle durability, swift charge/discharge rates, exceptional chemical as well as thermal endurance, diversity in electrode design, and inexpensive production costs. In light of these benefits, PDI-based MOFs are intriguing options for utilization in energy storage. Inspired by the distinctive features of perylene diimide-based ligands, highly conjugated and nitrogen-rich organic ligands Perylene diimide-L-dopa (PDI-L-Dopa) were incorporated to create the Ni-MOF architecture. The resulting hierarchical flower-like microspheres of bi-ligand Ni-MOF had better electron transport, conductivity, and wettability. When applied as electrode material in a three-electrode system considering a specific capacitance of 198 F/g at a current density of 1 A/g, the Ni-MOF-24 h electrode showcased beneficial electrochemical efficiency. XRD, FT-IR, and XPS were used to validate the formation of Ni-MOF and disclose the exact chemical composition and valence state inside the material. The hierarchical flower-like microsphere structure of the Ni-MOF, formed of 2D petal-like nanosheets, was revealed by FE-SEM and TEM. Additionally, when Ni-MOF-24 h electrodes used to fabricate symmetric supercapacitor (SSC), it reveals a high energy density (Ed) of 23 Wh/kg at a corresponding power density (Pd) of 600 W/kg along with extraordinary cyclic stability over 10,000 charge/discharge cycles with retaining 99 % of the initial capacitance. This research sheds light on the design and manufacture of innovative materials for long-term and efficient energy storage devices based on MOFs.

In situ tellurization strategy for crafting nickel ditelluride/cobalt ditelluride hierarchical nanostructures: A leap forward in hybrid supercapacitor electrode materials

Advancements in renewable energy conversion can be significantly propelled by optimizing the performance of transition-metal-based electrodes. In this study, we introduce an innovative, in situ tellurization strategy to synthesize novel, flower-like hierarchical structures of nickel ditelluride/cobalt ditelluride (NiTe2/CoTe2) on a nickel foam substrate (labeled as NF/FNCT), making them promising candidates for electrodes in hybrid supercapacitors. Initially, we utilized a hydrothermal method to create flower-like NiCo-layered double hydroxide (NiCo-LDH) nanoarrays on nickel foam (NF/FNCLDH). This process was followed by the tellurization of these nanoarrays, which yields the NiTe₂/CoTe₂ nanostructures. The strategic assembly of active materials on a conductive substrate effectively obviates the need for inert, slow-conductive binders, thereby facilitating redox chemistry. Capitalizing on the synergistic effects of the conductive tellurium and hierarchical flower-like nanomorphology, the NF/FNCT showcases expedited electron/ion transport, enhanced efficiency, and exceptional electrochemical performance. The NF/FNCT electrode discloses an impressive capacity of 1388.9 (±3) C/g, superior rate capability (83.45 % capacity retention at 30 A/g), and remarkable cycling durability of 96.67 %. Furthermore, when integrated with activated carbon (AC), the resultant hybrid supercapacitor delivers a desirable energy density of 58.85 Wh kg−1 at a power density of 806.85 W kg−1, demonstrating commendable rate capability and cycling durability. This investigation opens new avenues for the synthesis of materials for hybrid supercapacitors.

Effects of pH and ascorbic acid on the synthesis of Bi-modified bismuth oxyiodide composite catalysts

Multi-heterojunction composites exhibit unparalleled superiority in light absorption and spatial separation of charges, but their synthesis remains a challenge. Herein, we report the one-step hydrothermal synthesis of Bi-modified bismuth oxyiodide composites by modulating the pH of the reaction system using ascorbic acid (AA) as reducing agent. The pH highly influences the composition, morphology and properties of the samples. AA can reduce Bi3+ to metallic Bi, inhibit grain growth of BiOI and help to form Bi4O5I2, thus realizing the one-step synthesis of ternary composites. The sample obtained at pH 6.5 and AA of 0.24 g is the BiOI/Bi/Bi4O5I2 composites with flower-like hierarchical structure, which has the highest degradation efficiency for bisphenol A and RhB. In addition, formation mechanism of the composites was systematically researched based on the composition of intermediates, and an indirect Z-scheme photocatalytic mechanism of BBI-AA-0.24 based on the electronic bridge of metal Bi was proposed.

An insight on the growth mechanism of Cu2ZnSnS4 via hydrothermal route

In the current study, we successfully prepared Cu2ZnSnS4 (CZTS) microparticles using the hydrothermal method at 180 °C, where thiourea was used as a sulphur precursor. To investigate the growth mechanism of CZTS, time-dependent X-ray diffraction (XRD)pattern was studied. The morphology and shape of the synthesized microparticles were examined by field emission scanning electron microscopy (FE-SEM). UV-DRS(UV- Diffusion Reflectance Spectrometer) studies were used to study the optical properties. The morphology played a vital role in the formation of CZTS. This is clearly observed in SEM images where there is a transformation from agglomeration to a hierarchical flower-like structure. The synthesized powder using hydrothermal processes demonstrated the Cu2ZnSnS4 is formed in kesterite phase. The band gap of as-produced CZTS microparticles determined by UV-DRS spectra measurements was 1.57 eV, which is close to the ideal value for photo absorption applications. We analyze the changes in surface properties of particles using X-ray photoelectron spectroscopy (XPS). Understanding the mechanism in preparation of such hierarchical flower like CZTS enables the application of such structure in a wide sector, including photocatalysis and photovoltaics.

Gas-sensing properties and first-principles comparative study of metal (Pd, Pt)-decorated MoSe2 hierarchical nanoflowers for efficient SO2 detection at room temperature

The online detection and control of concentration for agricultural greenhouse gas SO2 is an important technology to ensure normal agricultural production. This paper reports on a facile hydrothermal method to synthesis Pd-decorated and Pt-decorated MoSe2 nanomaterials, i.e. multistage flower-like structures with attached nanometallic particles and nanosheets hierarchical structures. The Pd/MoSe2 and Pt/MoSe2 hierarchical materials were characterized for the nanostructure, microscopic morphology and elemental compositions. The gas-sensing properties results show that the Pd/MoSe2 and Pt/MoSe2 nanofilm sensors have good sensitivity, stability and response rate to SO2 gas. The response values for the metal Pd and Pt decorated samples to 20 ppm SO2 were 2.04 and 3.42 times higher than those for the intrinsic MoSe2 samples at room temperature. The hierarchical flower-like structure proved to be beneficial in providing more adsorption drop points. In addition, based on the first-principles, the geometrical parameters and electronic properties of the metal-decorated modified structures were calculated to comparatively investigate the enhanced sensing mechanism of SO2 by nanoflower materials. The Pt-MoSe2 nanofilm sensor achieves a high sensitivity detection with a response value of 2.89 for low concentration (1 ppm) of SO2, which is confirming the promotion of charge transfer by metal decorating. This study suggests that Pd-MoSe2 and Pt-MoSe2 hierarchical structures may be recommended for the detection of the agricultural greenhouse gas SO2.

BiOCl/SrHA nanoparticle for photocatalytic degradation of a malachite green dye

In this research, we discuss the removal of malachite green dye by strontium hydroxyapatite supported BiOCl. A modified hydrolysis model, one can synthesise BiOCl/SrHA. BiOCl/SrHA was characterized using Fourier transform-infrared spectroscopy (FTIR), UV-visible (UV-vis) analysis, X-ray diffraction (XRD), energy diffraction X-ray (EDX), and scanning electron microscopy (SEM). SEM outcome confirmed the dispersion of BiOCl onto strontium hydroxyapatite. The shape of the BiOCl catalytic samples overlapped with each other to form 3D hierarchical flower-like structures. The UV-visible was used as a radiation source during photocatalysis. BiOCl/SrHA had an effect on malachite green dye degradation. The oxidative removal occurred through hydroxyl radical formation. UV-visible (UV-vis) /BiOCl/SrHA showed perfect photocatalytic property for the decay of malachite green (MG) from an aqueous solution. According to kinetics analysis, the dye degradation rates could be in a pseudo-first-order model.

Bismuth oxyiodide nanocomposites supported on strontium hydroxyapatite enhance UV-Vis light-driven photocatalytic activity

In this research, we discuss the removal of basic fusion (BF), and crystal violet (CV) dyes by strontium hydroxyapatite supported BiOI. In a modified hydrothermal model, one can synthesize BiOI/SrHA. BiOI/SrHA was characterized using Fourier transform-infrared spectroscopy (FTIR), UV-visible (UV-vis) analysis, X-ray diffraction (XRD), energy diffraction X-ray (EDX), and scanning electron microscopy (SEM). SEM outcome confirmed the dispersion of BiOI onto strontium hydroxyapatite. The shape of the BiOI catalytic samples overlapped with each other to form 3D hierarchical flower-like structures. The UV-visible was used as a radiation source during photocatalysis. BiOI/SrHA had an effect on malachite green dye degradation. The oxidative removal occurred through hydroxyl radical formation. UV-visible (UV-vis) BiOI/SrHA showed perfect photocatalytic property for the decay of Basic Fuchsin (BF) and Crystal Violet (CV) from an aqueous solution. According to kinetics analysis, the dye degradation rates could be in a pseudo-first-order model

Facile fabrication of three-dimensional MnO2 for trichloroethylene degradation by plasma catalysis

Non-thermal plasma (NTP) coupled with catalyst is a cutting-edge technique for the abatement of chlorinated volatile organic compounds (Cl-VOCs), which are typically chemically stable, highly toxic and non-biodegradable. In this study, different morphologies of 3D MnO2 catalysts were fabricated facilely through a hydrothermal method and coupled with NTP for trichloroethylene (TCE) degradation. Among the various catalysts tested, MnO2 IV exhibited the highest TCE degradation performance, with removal efficiency, mineralization and energy yield ranging from 44.3% to 94.8%, 28.9% to 90.1% and 5.76 to 2.31 g/kWh, respectively, at voltage levels between 7 and 11 kV. The relationship between the physicochemical properties of the catalysts and their degradation performance was established through various characterization methods. The exceptional catalytic efficiency of MnO2 IV can be ascribed to its hierarchical flower-like structure, the greatest specific surface area (120 m2/g), the weakest Mn-O bonds, increased lattice defects and oxygen vacancies, and lower H2 reduction temperature. These characteristics facilitate enhanced transfer, adsorption, and utilization of reactive oxygen species in NTP on the surface of MnO2 IV, promoting the deep oxidation of TCE. The optimization of operational parameters was achieved using response surface methodology, with results indicating that the applied voltage exerted the greatest influence on both the mineralization rate and energy yield. The optimal operating conditions were determined, with initial TCE concentration, applied voltage, and gas flow rate values identified as 393 ppm, 7.3 kV, and 0.83 L/min, respectively. Lastly, the TCE degradation mechanism in the NTP-MnO2 catalyst system was hypothesized based on the identification of various plasma reactive species and organic intermediates. This study provides new insights for the improvement of the VOCs oxidation performance in plasma catalytic system.

Energy band-adjusted BiPO4/BiOClxBr1-x photoelectrochemical sensor for enhancing 4-CP detection

BiPO4 nanoparticles were loaded into BiOClxBr1-x with hierarchical flower-like structures by hydrothermal method, and an energy band-adjusted BiPO4/BiOClxBr1-x heterojunction with high photoelectrochemical properties was synthesized. Comparing BiPO4 and BiOClxBr1-x to BiPO4/BiOClxBr1-x, improved photoelectrochemical properties are obtained on BiPO4/BiOClxBr1-x. The high performance of BiPO4/BiOClxBr1-x may be attributed to the formation of junction between BiOClxBr1-x and BiPO4, efficiently enhancing charge separation and lowering the recombination rate of photogenerated carriers. The PEC sensor was optimized by adjusting the Cl/Br molar ratio of BiPO4/BiOClxBr1-x. The optimal coupling of the oxidation efficiency and light absorption capacity in various band structures is what causes the 5% BiPO4/BiOCl0.75Br0.25 heterojunction to exhibit the maximum photoelectrochemical activity. The PEC sensor of 5% BiPO4/BiOCl0.75Br0.25 heterojunction presents the low detection limit of 0.11 nM (S/N = 3), and it also exhibits high linear ranges (R2 = 0.9927) of 2–20 μM with good selectivity and stability for the 4-CP detection.

The electromagnetic wave absorption composite of flower-like structure NiCo2O4 and Fe3O4 derived from low-temperature preparation method

The NiCo2O4@Fe3O4 composites with excellent electromagnetic wave absorption performance was prepared by the low-temperature (50 °C) co-precipitation method, avoiding the traditional high-temperature hydrothermal synthesis method. The specific surface area of the composite material was increased due to the combination of NiCo2O4 with 3D hierarchical flower-like structure and Fe3O4 with spherical structure, which is conducive to the full reflection and scattering of electromagnetic waves. The combination of typical magnetic material and excellent dielectric material could adjust the impedance matching value of the material and thus the absorption loss performance of electromagnetic wave was improved. The ε value of the dielectric material was larger than those of magnetic materials and the maximum reflection loss value appeared at the high frequency (the thickness is small), while the μ value of magnetic materials was larger than those of dielectric materials and the maximum reflection loss value generally appeared at low frequency (the thickness is large).The results showed that the maximum RL value reached −53.35 dB at about 13 GHz with the thickness of 2.0 mm and the effective absorption bandwidth was 4.4 GHz when the weight ratio (NiCo2O4:Fe3O4) of composite samples was 6:1. The excellent EMW absorption property was mainly due to the combination of NiCo2O4 and Fe3O4, which could achieve impedance matching to loss EMW by dielectric loss and magnetic loss.

Dual co-catalysts Ag/Ti3C2/TiO2 hierarchical flower-like microspheres with enhanced photocatalytic H2-production activity

Solar-powered semiconductor photocatalysis is considered a powerful strategy for addressing environmental pollution and energy crisis. Nevertheless, the separation and transfer abilities of photogenerated photocatalysts remain unsatisfactory. Herein, dual Ti3C2 nanosheets/Ag co-catalysts synergistically decorated hierarchical flower-like TiO2 microspheres for boosting photocatalytic H2 production were fabricated by electrostatic self-assembly and subsequent photoreduction procedures. The optimal Ag/Ti3C2/TiO2 composite demonstrated an excellent photocatalytic H2-production rate of 1024.72 μmol g−1 h−1 under simulated solar irradiation, achieving nearly 40, 2.3, and 1.8 folds with respect to that obtained on pristine TiO2, optimized Ti3C2/TiO2 composite, and Ag/TiO2 composite, respectively. The considerably improved photocatalytic H2-production activity is associated with the synergistic effect of the hierarchical flower-like structure of TiO2, excellent electrical conductivity of Ti3C2, and surface plasmon resonance effect of Ag, which enhances the light absorption capacity and promotes the separation and transfer of photogenerated carriers. This study provides insight into the design of high-efficiency photocatalysts with dual co-catalysts for solar H2 production.

Fabrication of ultrahigh supercapacitor device based on ZnCo2O4@MnO2 with porous nanospheres decorated on flower-shaped structure

Being a fundamental component of energy storage devices, high-performance supercapacitors are always of utmost significance. In addition to long-term cycle durability, these supercapacitors should have higher power and energy densities. So, here we report an innovative approach for designing the hierarchical flower-like structures of binary metal oxides decorated with porous nanospheres of manganese oxide. The synergistic coupling of ZnCo2O4 and MnO2 offers a twofold charging capacity, while the porous framework provides good accessibility to the ions of electrolytes for storage inside the material. Furthermore, the Asymmetric device (ASD) is fabricated to achieve high energy density by employing ZnCo2O4@MnO2 as an anode material and activated carbon as a cathode material. The fabricated device exhibits an ultrahigh energy density of 247 Wh/kg at 1250 W/kg power density and good cycle stability after 5000 charge-discharge cycles with 97.2 % retention. Moreover, an array of 51 LEDs is lightened for nearly 16 min by connecting six asymmetrical devices in series to each other. As an astonishing result of the fabricated electrochemical asymmetric supercapacitive device, it holds great promise for industrial energy storage solutions.