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In this paper, α-CaSiO3/Al2O3-Li2CO3 was prepared by traditional solid-state method with Li2CO3 as low-temperature sintering aid added to α-CaSiO3/Al2O3 ceramics. The effects of different Li2CO3 content on the sintering properties, microstructure, and microwave dielectric properties of α-CaSiO3/Al2O3 ceramics were studied. The phase structure, micro-morphology, and microwave dielectric properties were characterized by X-ray diffractometer, scanning electron microscope, and network analyzer. The aim of this paper is to reduce the sintering temperature and improve the microwave dielectric properties of α-CaSiO3/Al2O3 ceramics by controlling the phase structure of ceramics. The results revealed that Li2CO3 additives can not only reduce the sintering temperature from 1375 to 975 °C, but also can transfer the major phase composition from α-CaSiO3 to β-CaSiO3. The density of the microwave dielectric ceramics with 3 wt% Li2CO3 additives sintered at 975 °C can reach the optimal microwave dielectric properties with er = 6.21, Q × f = 30,471 GHz, and τf = − 34.58 ppm/°C.

One-dimensional MoO3/ZnMoO4/CoMoO4 hierarchical structures with sequential layered and granulated constitutional units on surfaces have been successfully designed and fabricated, mainly derived through the introducing of bi-component MOF and the effective element migration mechanism. Based on the different adding ratios of Co and Zn sources, the obtained hierarchical structure can be composed of the central MoO3 nanobelts, the outer uniform ZnMoO4 shell, and the outermost tunable CoMoO4 nanoparticles. The well-organized ZnMoO4 shell and CoMoO4 nanoparticles grown on MoO3 surface provide favorable opportunities for improving the surface absorption and chemical reaction, electron transport paths, and electron transfer efficiency. Compared with MoO3 nanobelts and MoO3/ZnMoO4 composites, the optimal MoO3/ZnMoO4/CoMoO4 sensors exhibit superior gas-sensing response value of 505.67 for 10 ppm triethylamine (TEA) at 270 °C as well as excellent gas selectivity and long-term stability. The superior gas-sensing performance is mainly attributed to the combination of the designed multi-level effective heterojunctions, large specific surface area, the enhanced surface adsorption/reaction, and the particular surface/interface electron transport process. More importantly, the current work presents a new insight of original gas-sensing MoO3/ZnMoO4/CoMoO4 hierarchical structures for detecting the variation of freshness in shrimp storage, indicating the practical applications in chemical detector and biosensor fields.

In this study, for the first time, a Cu+-doped PbBrOH red phosphor (PbBrOH:Cu) was successfully synthesized by a hydrothermal method. The crystal structure, microstructure, optical properties, luminescence mechanism, and environmental stability of the PbBrOH:Cu phosphor were discussed in detail. PbBrOH and PbBrOH:Cu phosphor synthesized by the hydrothermal method are needle-like transparent grains. The excitation wavelengths of the PbBrOH and PbBrOH:Cu phosphor were both 353 nm. Under the excitation of this wavelength, weak blue emission and excellent red emission were observed. Based on first-principles calculation, ultraviolet and visible (UV-vis) spectrophotometry, and ultraviolet photoelectron spectroscopy (UPS) analysis, we concluded that the luminescence type of the phosphors was bandgap luminescence. The addition of Cu+ significantly reduced the bandgap, produced defect levels, and promoted the electron transition between the bandgaps, which led to the strong red emission of PbBrOH:Cu under UV excitation. It is worth noting that the PbBrOH:Cu phosphor shows excellent environmental stability and excellent luminescence performance when it is used in organic solvent immersion experiments and manufacturing LED lamp beads. Therefore, the PbBrOH:Cu phosphor synthesized in this study is expected to be a strong candidate as the red phosphor component in white LEDs.

Development of high efficient and stable water oxidation catalysts is essential for the realization of industrial water-splitting systems. Herein, a novel approach involving an in-situ transformation of Co(OH)2 nanosheets into NH4CoPO4•H2O nanoplates on Co foil is reported. As a 3D self-supported oxygen revolution reaction (OER) electrocatalyst, the as-prepared NH4CoPO4•H2O/Co exhibits remarkable catalytic activity and exceptional stability. Specifically, it can deliver a current density of 10 mA cm−2 at a quite low overpotential of 254 mV with a small Tafel slope of 64.4 mV dec−1 in alkaline electrolyte. Through experimental study and theoretical analysis, the excellent OER performance can be attributed to enriched exposed active sites, favorable electron/proton transfer and mass transport, and its unique asymmetric local atomic and electronic structure. Thus, this present research not only provides a practicable in-situ transformation strategy to design 3D self-supported electrocatalysts, but also enlightens a new way of developing transition-metal phosphates for efficient and stable water oxidation at atomic level.

Development of efficient and stable electrodes for electrocatalytic oxygen evolution reaction (OER) is essential for energy storage and conversion applications, such as hydrogen generation from water splitting, rechargeable metal–air batteries and renewable fuel cells. Alkali metal cobalt phosphates show great potential as OER electrocatalysts. Herein, an original electrode design strategy is reported to realize an efficient OER electrocatalyst through engineering the coordination geometry of Co(II) in KCoPO4·H2O by a facile dehydration process. Experimental result indicated that the dehydration treatment is accompanied by a structural transformation from orthorhombic KCoPO4·H2O to hexagonal KCoPO4, involving a concomitant coordination geometry evolution of Co(II) from octahedral to tetrahedral configuration. More significantly, the local structural evolution leads to an advantageous electronic effect, i.e. increased Co–O covalency, resulting in an enhanced intrinsic OER activity. To be specific, the as-produced KCoPO4 can deliver a current density of 10 mA cm−2 at a low overpotential of 319 mV with a small Tafel slope of 61.8 mV dec−1 in alkaline electrolyte. Thus, this present research provides a new way of developing alkali metal transition-metal phosphates for efficient and stable electrocatalytic oxygen evolution reaction.

Here, a dual-modification strategy using KMnO4 (potassium permanganate) and AlCl3·6H2O (aluminum chloride, hexahydrate) as co-modifiers to improve the Cr(VI) removal capacity of K2CO3 activated biochar is introduced. As a result, the dual-modified biochar with KMnO4 and AlCl3·6H2O has the calculated adsorption energy of −0.52 eV and −1.64 eV for HCrO4−, and −0.21 eV and −2.01 eV for Cr2O72−. The Al2O3 (aluminum oxide) and MnO (manganese oxide) embedded on the surface of dual-modified biochar bring more Cr(VI) absorption sites comparing to single-modified biochar, resulting in a maximum Cr(VI) saturated adsorption capacity of 152.86 mg g−1. The excellent removal performance is due to the synthetic effect of electrostatic attraction, reduction reaction, complexation reaction, and physical adsorption. The experimental results also indicated that the spontaneous adsorption process agreed well with the pseudo-second order and Langmuir models. This dual-modification strategy is not limited to the treatment of Cr(VI) with biochar, and may also be incorporated with the treatment of other heavy metals in aqueous environment.

One-step single-spinneret electrospinning synthesis of 1D fibrous hierarchical structure can not only prevent the agglomeration or restacking of fibers or particles and enlarge surface active area but also promote the directional migration of electrons in materials and achieve effective regulation of resistances. Herein, tunable SnO2 and SnO2/ZnO fibrous hierarchical structures with in situ growth of monodisperse spherical-like particles on surface provide a new sight for adjusting component distribution, surface absorption and chemical reaction, electronic transmission path, and electron transfer efficiency. Compared with SnO2 porous fibers and SnO2 hierarchical structures, the optimal SnO2/ZnO sensors exhibit superior gas-sensing response value of 366-100 ppm ethanol at 260 °C as well as excellent gas selectivity and long-term stability, in which the enhanced gas-sensing mechanism is primarily derived from multilevel effective heterojunctions with unique interface electronic effects. Especially, these SnO2-based sensors can achieve favorable linear relationship of the response and gas concentration for sensitive trace detection in cosmetics for the first time, providing a new strategy to design composite materials for quantitative analysis of volatiles in the cosmetics evaluation process.

Tetragonal zircon BiVO4 (P-BiVO4) were grown on fluorine-doped tin oxide (FTO) glass via hydrothermal method. The cathodic photocurrent and Mott-Schottky analysis indicate that the tetragonal zircon BiVO4 is a p-type semiconductor. Inductively coupled plasma (ICP) analysis and X-ray photoelectron spectrum showed that there are Bi vacancies and interstitial oxygen exist in the crystal, which are the origin of the p-type conductivity. The flat band potential of the P-BiVO4 is about 1.33 V (vs Ag/AgCl) inferred from Mott-Schottky plots. Combining with diffuse reflection spectrum and valence band X-ray photoelectron spectrum, the calculated conduction band value of the P-BiVO4 is about 0.06 V vs RHE, slightly higher than the reduction potential of hydrogen. However, the P-BiVO4 exhibit hydrogen production activity under Xe light irradiation even though its conduction band level is not negative enough. This can be attributed to the hot carrier processes in p-type semiconductors.

Hierarchical WO3/ZnWO4 1D fibrous heterostructures with tunable in-situ growth of WO3 nanoparticles on surface have been fabricated by the original one-step electrospinning technology combined with subsequent calcination process. Phase composition and morphology can be transformed from bead-like WO3 fibers to hierarchical WO3/ZnWO4 1D composites with the introduction of ZIF-8 into the precursor solution, which was mainly attributed to the combination of nucleation competition and crystal planes matching mechanisms during heat treatment. Compared with pure WO3 and WO3/ZnWO4-10%, WO3/ZnWO4-5% displayed the highest specific surface area value evaluated to be 268.57, indicating the prominent enhanced absorption behavior for targeted organic species. It is found that WO3/ZnWO4-5% composites have a response about 44.5 for 5 ppm HCHO, which was almost 8 times higher than that of sensor based on pure WO3 nanofibers at the optimal operating temperature. Meanwhile, the fast response/recovery time (12/14 s) and excellent stability characteristics (recycling, long-term, and humidity stability) towards HCHO can be also observed for WO3/ZnWO4-5% samples. The enhanced gas-sensing mechanism based on WO3/ZnWO4 composites can be ascribed to the synergistic effect of effective heterojunctions, large specific surface area, multiple reaction sites, and unique surface/interface electron transmission. The design and construction of hierarchical WO3/ZnWO4 1D materials attest to the significant potential of their use as novel gas sensors for detecting low concentration HCHO.

Morphology-tunable C–N/SnO2-based hierarchical microspheres with good gas sensitivity for triethylamine (TEA) have been fabricated via facile electrospinning and a subsequent calcination process. The reaction temperature and modifying calcining technology played a dominant role for the morphological evolution from precursor fibers to microspherical shapes and the formation of C–N-decorated SnO2 phase composition. C–N/SnO2/ZnO composites with tunable crystallinity, microstructure, and gas-sensing performance were strictly dependent on the added amount of Zn element. Fascinatingly, the constructed C–N/SnO2/ZnO/Au composites can not only precisely regulate the crystal size, dispersion status, loading position, and content of Au nanoparticles but also display excellent gas-sensing properties with ultrasensitivity and high selectivity under various temperature detections. The response of C–N/SnO2/ZnO/Au composites can reach up to approximately 1970, calculated to be 121.6 and 23.6 times for 50 ppm TEA molecule...

Development of efficient and stable electrodes for electrocatalytic oxygen evolution reaction (OER) is essential for energy storage and conversion applications, such as hydrogen generation from water splitting, rechargeable metal-air batteries and renewable fuel cells. Alkali metal cobalt phosphates show great potential as OER electrocatalysts. Herein, an original electrode design strategy is reported to realize an efficient OER electrocatalyst through engineering the coordination geometry of Co(ii) in KCoPO

MoS2/CoS2 heterostructures on nitrogen-doped carbon nanosheets as an efficient electrocatalyst for hydrogen evolution reaction (HER) are prepared using zeolitic imidazolate frameworks-67 as precursors. Two dimensional (2D)/2D MoS2/CoS2 heterostructures consist of layered CoS2 and MoS2. The (210) facet of CoS2 and the (002) facet of MoS2 contacted vertically resulted in improved electrons and holes transfer in the interface. The ratios of CoS2/MoS2 plays an important role to get high performance (CoS2/MoS2/NC-n%, e.g. n = 20, 25, 30, 35 wt%). Meanwhile, sample CoS2/MoS2/NC-25% revealed the best HER activity, suggesting the sample has the largest number of active sites and the fastest electron transfer rate. In addition, sample CoS2/MoS2/NC-25% exhibited the lowest onset potential of 51 mV, the lowest potential of 215 mV at 10 mA cm−2, and the smallest Tafel slope of 80.0 mV dec−1. The result is utilizable for the construction of heterostructures with excellent HER performance.

Various α-Fe2O3 micro/nanostructures referring to spherical-like, bowl-like, cubic, and discoid shapes have been fabricated by a facile hydrothermal method using sodium bicarbonate as surfactant and alkaline reagents, displaying superior Fenton catalytic performances for degradation of Rhodamine 6G. Because of abundant exposed crystal surfaces such as (110) and (104) on the surfaces of bowl-like α-Fe2O3, the rapid degradation rate of 90.0% in 5 min is observed under the dark condition as the adding amount of H2O2 limiting to 300 μL. Significantly, the enhanced catalytic performances of bowl-like α-Fe2O3/Au catalysts under natural light condition have been investigated and carried out by in situ reduction of well-distributed Au nanoparticles with average sizes of 3–6 nm. Due to the appropriate phase structures and heterogenous interface properties, the highest photo-Fenton catalytic activity with the degradation rate of 90.0% in 2 min can be obtained for α-Fe2O3/Au0.01 composites.

A series of hexagonal-like α-Fe2O3/ZnO/Au nanoplate heterostructures with tunable morphologies and superior ethanol gas-sensing performance were successfully synthesized via the facile multi-step reaction processes. Hexagonal-like α-Fe2O3 nanoplates with uniform size around 150 nm are employed as new sensor substrates for loading the well-distributed ZnO and Au nanoparticles with adjustable size distribution on the different surfaces. Brunauer-EmmeQ-Teller (BET) surface areas of α-Fe2O3 and α-Fe2O3/ZnO samples are evaluated to be 37.94 and 61.27 m2/g, respectively, while α-Fe2O3/ZnO/Au composites present the highest value of 79.08 m2/g. These α-Fe2O3-based functional materials can exhibit outstanding sensing properties to ethanol. When the ethanol concentration is 100 ppm, the response value of α-Fe2O3/ZnO/Au composites can reach up to 170, which is 14.6 and 80.3 times higher than that of α-Fe2O3/ZnO and pure α-Fe2O3, respectively. The recycling stability and long-time effectiveness can be availably maintained within 30 days, as well as the response and recovery times are shortened to 4 and 5 s, respectively. Significantly, the response value of α-Fe2O3/ZnO/Au composite is still up to 63 at an operating temperature of 280 °C even though the ethanol concentration decreases to 10 ppm. The enhanced gas sensing mechanism would be focused on the synergistic effects of phase compositions, surface heterogeneous structures, large specific surface area, and the selective depositions of Au nanoparticles in α-Fe2O3/ZnO/Au sensors. The synergistic effect of different surface heterostructures referring to α-Fe2O3/Au and α-Fe2O3/ZnO/Au and their novel electron transport processes on the surfaces are first investigated and discussed in details. It is expected that hexagonal-like α-Fe2O3/ZnO/Au nanoplate heterostructures with excellent sensing performance can be the promising highly-sensitive materials in the actual application for monitoring and detecting ethanol.

Triangular- and circular-like Ag/AgCl nanoplates with various edge length and thickness have been successfully synthesized by a facile in situ oxidation process. Uniform Ag triangular nanoplates with tunable sizes and thicknesses obtained by adjusting the adding amounts of trisodium citrate and polyvinylpyrrolidone (PVP) were employed as Ag precursors to form triangular- and circular-like Ag/AgCl heterostructures by changing the adding amounts of FeCl3 in the reaction process. The morphological evolution mechanism of Ag nanoplates and Ag/AgCl heterostructures was discussed. It is clear that the morphologies of Ag/AgCl products can be gradually converted from the large and thick triangular-like nanoplates into the small and thin circular-like ones as the AgCl ratio increasing from 5 to 100%, which can be mainly assigned to the synergistic effect of the oxidation of Fe3+ and the etching action of Cl-. The photocatalytic results indicate that Ag/AgCl nanoplates with different ratios of AgCl can exhibit good photocatalytic activity for degradation of methyl orange (MO) pollutant under ultraviolet-light-driven (UVD) and visible-light-driven (VLD) irradiation, respectively. The Ag/AgCl nanoplates with an AgCl ratio of 30% have the superior photocatalytic activity with the photocatalytic efficiency calculated to be 83.5% within 160 min under UVD irradiation and 53.6% within 240 min under VLD irradiation, respectively, owing to the combination of the favorable crystallinity, excellent photoabsorption, and the efficient separation of the photo-induced carriers between Ag and AgCl.

Uniform bead-like CuMn2O4/ZnO nanofibers were successfully fabricated via a facile electrospinning technology. The current new findings can be emphasized on the introduction of ZIF-8 into Cu-based precursor solution that had a great significance for controlling phase structure and morphology of CuMn2O4/ZnO composites. Compared with hollow CuMn2O4 nanofibers and CuMn2O4/ZnMn2O4 irregular rod-like materials, CuMn2O4/ZnO nanofibers can display the enhanced photocatalytic efficiency of 86% as the irradiation time increasing to 50 min and the good photocatalytic cycle stability to methylene blue (MB). The influence of adding amount of ZIF-8 on the morphological evolution and photocatalytic property of CuMn2O4/ZnO nanofibers and the relevant photocatalytic mechanism were investigated. The synthesis approach of CuMn2O4/ZnO nanofibers is expected for fabricating other 1D semiconductor composites with novel morphologies and advanced properties in photocatalysis, gas sensing, and electrochemical applications.

Morphology-controlled porous α-Fe2O3/SnO2 nanorods with uniform surface heterostructures have been fabricated by a facile surface modification of rod-like α-Fe2O3 nanomaterials by changing the adding amount of Sn composition, displaying the excellent selectivity and sensitivity of gas-sensing to acetone. The introduction of SnO2 nanoparticles had the great effects on tuning the crystal size, crystallinity, and surface status, as well as the structural stability and phase distribution of α-Fe2O3/SnO2 nanorods. Compared to pure α-Fe2O3, α-Fe2O3/SnO2 heterostructures can exhibit the optimal gas-sensing behavior with the sensitivity up to 53.1 and the response and recovery times decreasing to 9 and 2.5 s at the operating temperature of 260 °C, respectively. The enhanced gas-sensing performance can be mainly attributed to the combination of uniform porous structures, narrow size-distribution, large specific surface area, and heterostructures of the interface between α-Fe2O3 and SnO2.

The highly-dispersed carambola-like SnO 2 /C composite microparticles have been fabricated through a novel electrospun approach using tetrobutylammonium bromide and paraffin liquid as functional additives in the precursor solution. The presence of carbon matrix can availably contribute for the reduced agglomeration, decreased migration, and controllable sizes of SnO 2 nanocrystals. The influence of calcination temperature on the microstructures and photocatalytic properties of SnO 2 /C products and the relevant photocatalytic mechanism were investigated. The carambola-like SnO 2 /C photocatalysts showed the superior photocatalytic performance for the degradation of rhodamine B (RhB) with the high efficiency of 94.6% as the irradiation time increasing to 210 min as well as the good photocatalytic cycle stability. The preparation technology can be potentially applied for adjusting microstructures of other inorganic oxide photocatalysts in the field of water treatment.

Red to near-infrared (NIR)-emitting ternary-alloyed CdTe (x) Se(1−x) (x = 0–0.3) quantum dots (QDs) with tetrapod and dot morphologies have been synthesized by a facile method using oleic acid (OA) as single capping agent. The controlled dot-shaped and tetrapod-shaped CdTe( x) Se(1−x) QDs can be successfully obtained by adjusting the content of Te element. It is clear that CdTe (x) Se(1−x) QDs display the tunable emission peaks from the visible light (613.4 nm) to the NIR range (791.6 nm). With an inorganic CdZnS shell coated on the surface of CdTe(0.1)Se(0.9) cores, the stability and PL efficiency of the resulting core/shell QDs can be improved dramatically, accompanied with the red-shift of emission peaks to longer wavelength (795.6 nm). Peculiarly, a large blue shift of emission spectrum of CdTe(0.3)Se(0.7)/CdZnS core/shell QDs is observed, which is mainly ascribed to the shrink of the size of QDs by the fracture of tetrapod arms.

The effects of calcination temperature, precursor content, holding time and heating rate on the morphology of WO3 nanofibers (NFs) prepared by electrospinning technology have been investigated systematically. The X-ray diffraction (XRD) patterns using Rietveld method indicated that average crystalline sizes of nanoparticles of WO3 NFs increase with increasing calcination temperature. Also, the crystallinity of the nanofibers increases with the rise of calcination temperature. The suitable precursor contents and holding time facilitate the formation of continuous and uniform NFs. The samples prepared by different heating rates showed that the WO3 NFs fabricated with heating rate of 5 °C/min possess the smallest and uniform nanoparticle sizes. The X-ray diffraction (XRD) patterns using Rietveld method exhibited that different heating rate had no significant influence on the crystallinity of WO3 NFs. Additionally, the experimental results of photocurrent responses and electrochemical impedance indicate that the WO3 NFs prepared by different heating rate have different photoelectrochemical performances.

One-step single-spinneret electrospinning synthesis of 1D fibrous hierarchical structure can not only prevent the agglomeration or restacking of fibers or particles and enlarge surface active area but also promote the directional migration of electrons in materials and achieve effective regulation of resistances. Herein, tunable SnO

Morphology-tunable C-N/SnO

ZnO flowers consisting of single crystal nanosheets with exposed { 1 1 ¯ 0 0 } facets were fabricated from trisodium citrate via hydrothermal at 180 °C. The single crystal nanosheet has the thickness of about 70 nm and a well-crystalline structure with dominant surfaces as { 1 1 ¯ 0 0 } planes. The site-specific nucleation-growth process contributes to the formation of hierarchical flower-like ZnO structures. The ZnO flowers exhibited white emission. The visible emission gradually decreased with time and the UV emission suggests that the recombined rate of photogenerated electrons and holes of samples varied with the synthesis parameters. The ZnO flowers displayed an enhanced photocatalytic performance compared with ZnO microspheres. The maximized exposure of the reactive { 1 1 ¯ 0 0 } facets also favors the enhanced photocatalytic performance. Additionally, the special loose structural feature with an open microstructure has more important influences on the photocatalytic activity than specific surface area.

One-dimensional ZnO nanostructures with various morphologies including nanotubes, nanobelts, solid fibers, nanochains, and porous nanotubes were created through adjusting the parameters in single-spinneret electrospinning and calcination processes. The evolution of morphology depended strongly on the viscosity of precursor solutions and calcination process. Namely, the nanotube was fabricated via a two-step calcination process while the nanochain and solid fiber were created using a one-step calcination process. The nanotubes consisted of small ZnO nanoparticles. Furthermore, the nanobelt was fabricated when much more zinc precursor was added to increase the viscosity of the precursor solution. A possible mechanism based on Kirkendall effect and the decomposition of polyvinyl pyrrolidone was proposed to explain the formation of ZnO nanotubes and other one-dimensional structures. The photocatalytic activity of these ZnO samples for the degradation of Rhodamine B under ultraviolet light was investigated, and nanobelts showed the best degradation efficiency. Besides, the deposition of Au nanoparticle on ZnO nanobelts can further enhance the photocatalytic performance due to the formation of ohmic contact.

Alkali metal cobalt phosphates show great potential as electrocatalysts for oxygen evolution reaction (OER). Herein, a kind of layered potassium cobalt pyrophosphate dehydrate, i.e., K2Co3(P2O7)2·2H2O, was prepared by a simple hydrothermal method, and was proved to be a novel OER electrocatalyst for the first time. The as-developed K2Co3(P2O7)2·2H2O features a layered structure, large specific surface area, and special zigzag CoO6 octahedral chains, all of which contribute to the highly efficient OER performance. In specific, it achieves 10 mA cm−2 at an overpotential of only 296 mV and a Tafel slope of 40.2 mV dec−1 in 1.0 M KOH. Thus, this present work has opened a new pathway to develop alkali metal cobalt phosphates towards efficient and stable electrocatalytic oxygen evolution reaction.

This paper demonstrates a novel approach to prepare NH4CoPO4·H2O nanoplates on commercial Co foils via a chemical corrosion process. As a 3D self-supported oxygen revolution reaction (OER) electrocatalyst, the as-developed NH4CoPO4·H2O/Co exhibits remarkable electrocatalytic activity and exceptional stability. In specific, it can deliver a catalytic current density of 10 mA cm−2 at an ultralow overpotential of 262 mV. Notably, it can hold its catalytic performance for 100 h at least. The impressive catalytic activity can be mainly attributed to the 3D self-supported configuration that provides abundant exposed active sites and rapid charge transfer and mass transport.

This paper reports a simple and facile method to prepare surface functionalized commercial carbon cloth via a plasma treatment and its application in electrocatalytic oxygen evolution reaction (OER). It is observed that abundant oxygen containing functional groups formed on the surface of the treated carbon cloth. The functionalized carbon cloth (FCC) exhibits a remarkable of OER activity. Specifically, it can drive a current density of 10 mA cm−2 at a fairly low overpotential of 360 mV and a correspondent small Tafel slope of 66.7 mV dec−1. More unexpectedly, it was found that the OER activity of FCC follows the non-concerted proton-coupled electron transfer mechanism. A possible explanation was proposed that the surface carboxyl groups improve the proton-transfer kinetics, accelerating the deprotonation from OOH to OO* during the OER process.

We investigated the marked morphological changes of α-Fe2O3 nanocrystals from nanoplates to nanospindles via an environmentally friendly hydrothermal route. An aqueous Fe salt was used as the precursor and the volume ratio of ammonia to ethylene glycol was varied. The product was uniform and obtained at a high yield. By simply increasing the ratio of the aqueous phase, the morphology could be continuously tuned from nanoplates to nanospindles with the (001) facets gradually disappearing. A fundamental understanding of the shape evolution was obtained via a series of characterizations including X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The NO3− ions and NH3 molecules played vital parts at increased temperatures, not only in the phase structure of the iron oxide, but also in the formation of different hematite morphologies with different properties. The decrease in the photocatalytic efficiency in the visible region with the change from nanoplates to nanospindles under the same conditions indicated that the increase in the number of exposed (001) facets promoted the photocatalytic performance. The magnetic and electrochemical properties of typical morphologies were investigated and showed the potential applications of the nanostructures in various fields.

Highly luminescent hydrophobic CdSe and CdSe/CdxZn1−xS quantum dots (QDs) were synthesized via an organic route. The phase transfer of the QDs was carried out through a ligand exchange from 3-aminopropyltrimethoxysilane (APS) instead of an organic capping agent to get aqueous QDs. A functional sol–gel SiO2 sol with a high QD concentration was obtained from the aqueous QD colloidal solution with APS through the hydrolysis and condensation which subsequently occurred. Flexible inorganic SiO2 films with QDs were fabricated via various methods. The photodegradation experiments of the resulting films were completed. It is surprising that the QDs in films were revealed to be highly stable. Especially, the PL intensity of the films increased dramatically after irradiation by 365 nm UV light. By integrating a thin CdSe QD–silica film on a solar cell, the enhanced current demonstrated that a thin film can facilitate the continuous development of solar cells. Because of their high PL brightness, multicolor emission, flexibility and stability, these films will have great potential applications.

A sol–gel SiO2 film prepared from 3-aminopropyltrimethoxysilane (APS) has been developed as an excellent medium to encapsulate both hydrophobic and hydrophilic quantum dots (QDs). The film was fabricated by spin and dip coating on flat substrates as well as by a spraying approach on various substrates with a 3-dimensional (3D) surface. Pre-heat-treatment of the substrate plays an important role for creating homogeneous films on a 3D surface. In the case of aqueous CdTe and ZnSe0.9Te0.1 QDs, APS did not decrease the photoluminescence (PL) efficiency of the QDs. For hydrophobic QDs, a phase transfer from oil to water phase was first performed through the ligand exchange process between APS and the capping agent. By mixing QDs with different emitting colors, silica gel with white-light emission was obtained. Based on hydrophobic and hydrophilic QDs, white-light-emitting diodes with adjustable chromaticity coordinates were fabricated using a UV-emitting InGaN chip as excitation source. Because of the facile preparation procedure, high stability, and high PL efficiency, the magic film shows great potential for use in white-lighting-emission applications.

This paper reports a nanoflakes-assembled 3D flower-like nickel hydroxidenitrate (NiNH) and its application in water oxidation. It is demonstrated for the first time that the NiNH is an efficient oxygen evolution reaction (OER) electrocatalyst in alkaline solution. Specifically, it can drive a current density of 10 mA cm−2 at a fairly low overpotential of 280 mV and a correspondent small Tafel slope of 39.6 mV dec−1. The impressive OER catalytic activity of the as-prepared NiNH can be ascribed to its favorable 3D hierachical microstructure. The present research not only provide us a prospective and cost-effective electrocatalyst for water splitting but also affords us an inspiration for designing effective transition-metal based electocatalysts through microstructure regulation.

Nanosized Bi-based glass frit powders for silver front contact in crystalline silicon solar cells were prepared from a multicomponent gel in the Bi 2 O 3 –SiO 2 –B 2 O 3 –Al 2 O 3 –ZnO system. The phase structure of the glass frit was characterized by X-ray diffraction (XRD), which indicated that the xerogel was completely converted into amorphous glass after heat treatment at 500 °C. The glass frit showed excellent wetting behavior and etching effect on SiN x coating and silicon. The fabricated silicon solar cells containing the as-prepared nanosized glass frit as an inorganic binder showed higher fill factor (FF) and photoelectric conversion efficiency ( E ff ) when compared with those of the solar cells based on micron glass frit prepared by melt cooling route.

This paper reports a one-step synthesis of hybrid rod-like and spherical silver particles and its application in the silver front contact paste for crystalline silicon solar cells. The hybrid silver particles were synthesized by reducing silver nitrate in ethylene glycol. X-ray diffraction indicated that the hybrid silver particles were well crystallized with no crystallographic impurities. Scanning electron microscopy showed that the rod-like particles in the hybrid particles were 0.2 µm to 0.5 µm in width and 1 µm to 4 µm in length, and that the average size of the spherical particles was 0.5 µm. The fabricated crystalline silicon solar cell based on the as-prepared hybrid silver particles showed good photovoltaic performance.

This paper reports a new environmental friendly silver front contact paste for crystalline silicon solar cells. Quasi-spherical and high-dispersive silver particles were prepared from silver nitrate in hot ethylene glycol. Polyvinylpirrolidone (PVP) as a protective agent was added into the reduction system. Moreover, Bi-based glass frit powders with glass transition temperature ( T g ) of 385 °C were prepared by traditional melting route. The silver front contact paste for crystalline silicon solar cells was prepared using the as-prepared superfine silver particles and Bi-based glass frit powders. The microstructures of the conductive silver thick films were investigated, which indicated that the wetting behavior and etching effect of the glass frit on silicon nitride and silicon were efficient. Besides, silver particles were sintered well with the help of the glass frit during firing processing. The fabricated solar cell containing the Bi-based glass frit as an inorganic binder showed higher Fill Factor (FF) and electrical conversion efficiency ( E ff ) when compared with those of the solar cell fabricated with commercial Pb-based glass frit. In short, synthesis of silver particles in hot liquid polyols is a useful method for preparing superfine and high-dispersive particles. Moreover, the Bi-based glass frit could be a suitable substitute for Pb-based glass frit for preparing environmental friendly front-side silver paste for crystalline silicon solar cells.

A silanization process was employed to transfer hydrophobic quantum dots (QDs) prepared via an organic route at high temperature into water phase. The QDs were further coated with a thin organic SiO2 shell to form QDs@SiO2 composite nanoparticles by ligand exchange or remaining initial organic ligands on the surface. In this study, QDs with different ligands, either trioctylphosphine oxide (TOPO) or oleic acid (OA), were employed to investigate the effects of ligands on the reverse micelles in preparing QDs@SiO2 nanoparticles. In the preparing process, hydrophobic QDs were silanized by partially hydrolyzed tetraethyl orthosilicate (TEOS). For TOPO-capped CdSe QDs, surface TOPO ligands were completely replaced by partially hydrolyzed TEOS. As for OA-capped CdSe/Cd x Zn1−x S QDs, surface OA ligands were partially replaced. It was found that the ligand exchange drastically reduced the photoluminescence (PL) efficiency of CdSe QDs. Furthermore, the cytotoxicity studies of QDs@SiO2 have been carried out in detail. The results indicate that CdSe/Cd x Zn1−x S QDs@SiO2 composite nanoparticles exhibit lower cytotoxicity compared with CdSe QDs@SiO2, because the SiO2 shell and remained OA ligand layer can effectively prevent the leakage of toxic Cd2+ ions. Meanwhile, it was found that these CdSe/Cd x Zn1−x S QDs@SiO2 nanocomposites could keep excellent PL properties even for 24 h incubating with Siha cells, which indicating that our prepared composite nanoparticles are potentially applicable for cell imaging in biological systems.

High-dispersive spherical silver nanoparticles were prepared by solvothemal process, using ethylene glycol as solvent and reducing agent. The silver nanoparticles were characterized by X-ray diffraction and FESEM to analyze the size, shape and morphology. X-Ray diffraction (XRD) pattern indicated that the silver nanoparticles were well-crystallized with no crystallographic impurities. The average size calculated by Debye–scherrer’s fomula was 48 nm, which well agreed with the result of FESEM. From the FESEM, it was demonstrated that the silver nanoparticles were high-dispersive and spherical in shape. Thick silver films were prepared by screen-printing using the front contact silver paste containing the as-prepared silver nanoparticles. The experimental results indicated that the silver nanoparticles were favor to sintering of micro-size silver particles, and contributed to improve the photovoltaic performances of crystalline silicon solar cells.