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In this article, we report a simple ex situ Sn-doping method on hematite nanoflakes (coded as MSnO2-H) that can protect the nanoflake (NF) morphology against the 800 degrees C high-temperature annealing process and activate the photoresponse of hematite until 800 nm wavelength excitation. MSnO2-H has been fabricated by dropping SnCl4 ethanol solution on hematite nanoflakes homogeneously grown over the conductive FTO glass substrate and annealed at 500 degrees C to synthesize the SnO2 nanoparticles on hematite NFs. The Sn-treated samples were then placed in a furnace again, and the sintering process was conducted at 800 degrees C for 15 min. During this step, structure deformation of hematite occurs normally due to the grain boundary motion and oriented attachment. However, in the case of MSnO2-H, the outer SnO2 nanoparticles efficiently prevented a shape deformation and maintained the nanoflake shape owing to the encapsulation of hematite NFs. Furthermore, the interface of hematite/SnO2 nanoparticles became the spots for a heavy Sn ion doping. We demonstrated the generation of the newly localized states, resulting in an extension of the photoresponse of hematite until 800 nm wavelength light irradiation. Furthermore, we demonstrated that SnO2 nanoparticles can effectively act as a passivation layer, which can reduce the onset potential of hematite for water splitting redox reactions. The optimized MSnO2-H nanostructures showed a 2.84 times higher photocurrent density and 300 mV reduced onset potential compared with a pristine hematite nanoflake photoanode. Web of Science

Because of their high theoretical density, Li-air batteries (LABs) are expected to be critical components of future energy storage devices. However, the commercial use of LABs is limited by their low charge-discharge efficiency, high overpotential, and low cyclic stability. Therefore, to improve the cyclic stability of LABs, we manufactured N- and F-co-doped carbon quantum dots (NF-CQDs), thinly coated them on the surface of a Ni foam current collector via ultrasonic spray coating, and used the as-fabricated NF-CQD/Ni as the current collector of an LAB cathode. The NF-CQD/Ni-based cathode maintained remarkable cycling stability over 42 cycles (with a limited capacity was 1000 mAh/g) and exhibited a superior specific discharge capacity of approximately 5121.91 mAh/g (at 100 mA/g). NF-CQD/Ni-based cathode exhibits superior electrochemical properties, including its high cycling stability and high discharge capacity, primarily contributed by the NF-CQD coating layer, which prevented the oxidation of the Ni foam substrate and increased the electrical conductivity and electrocatalytic activity of the cathode. Therefore, NF-CQD/Ni can serve as an excellent current collector for LAB cathodes.

Despite their high energy density, the poor cycling performance of lithium–oxygen (Li–O2) batteries limits their practical application. Therefore, to improve cycling performance, considerable attention has been paid to the development of an efficient electrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Catalysts that can more effectively reduce the overpotential and improve the cycling performance for the OER during charging are of particular interest. In this study, porous carbon derived from protein-based tofu was investigated as a catalyst support for the oxygen electrode (O2-electrode) of Li–O2 batteries, wherein ORR and OER occur. The porous carbon was synthesized using carbonization and KOH activation, and RuO2 and Pt electrocatalysts were introduced to improve the electrical conductivity and catalytic performance. The well-dispersed Pt/RuO2 electrocatalysts on the porous N-doped carbon support (Pt/RuO2@ACT) showed excellent ORR and OER catalytic activity. When incorporated into a Li–O2 battery, the Pt/RuO2@ACT O2-electrode exhibited a high specific discharge capacity (5724.1 mA h g−1 at 100 mA g−1), a low discharge–charge voltage gap (0.64 V at 2000 mA h g−1), and excellent cycling stability (43 cycles with a limit capacity of 1000 mA h g−1). We believe that the excellent performance of the Pt/RuO2@ACT electrocatalyst is promising for accelerating the commercialization of Li–O2 batteries.

In this study, we designed a unique method for increasing F-doping concentration in F-doped SnO2 (FTO) films, without the extra addition of NH4F as a doping source, using NaOH acting as a functional additive during ultrasonic spray pyrolysis. The NaOH triggers a chemical reaction with HF, resulting in the presence of dissociated F− acting as a doping source. To optimize the NaOH effect on the transparent conducting performance in the FTO films, we adjusted the volume percentages of the NaOH to 0, 1, 5, and 10 vol% during FTO deposition. Compared with other FTO films, the FTO film prepared with 5 vol% NaOH revealed enhanced carrier concentration (7.81 × 1020 cm−3) generated by the increased F-doping concentration (3.57 at%) and high Hall mobility (27.18 cm2/(V S)) through smooth surface morphology. Such behaviors through the NaOH effect resulted in FTO films with decreased sheet resistance (5.3 ± 0.16 Ω/□), leading to improved electrochromic (EC) energy storage performances of fast switching speed (6.6 s for coloration speed and 8.4 s for bleaching speed) due to faster electrochemical kinetics at the active electrodes, high coloration efficiency (58.1 cm2/C) and high specific capacitance (65.2 F/g at 2 A/g) via enhanced electrochemical activity in the active electrodes that widens the transmittance modulation. Therefore, our study suggests a novel method to improve the transparent conducting performances of FTO films for application in EC energy storage devices.

In the present work, we report a preparation strategy for hematite phase-pure photoanodes consisting of Sn-doped hematite nanoflakes/hematite thin film bilayer nanostructure (Sn-HB). This approach is based on a two-step annealing process of pure iron films deposited on fluorine doped tin oxide (FTO) substrates by advanced magnetron sputtering. While the high density hematite ultrathin nanoflakes (HNs) with detrimental iron oxide layers (Fe3O4 and/or FeO) are generated during the first annealing step at 400 degrees C for two hours, the second thermal treatment at 800 degrees C for 15 minutes oxidises all the undesired iron oxide phases to a photoactive hematite layer as well as is providing efficient Sn doping of a drop-casted SnCl4 in order to increase the conductivity. The optimized Sn-HB shows an around 11 times higher photocurrent density (0.71 mA cm(-2) at 1.23 V-RHE) compared with a reference hematite photoanode produced from iron foil under the same conditions. Web of Science 9 11 art. no. E202200066

In this study, Fe co-doping into fluorine-doped tin oxide (FTO) films using horizontal ultrasonic spray pyrolysis deposition (HUSPD) is reported as a novel approach to improve their transparent conduction for high-performance electrochromic (EC) devices. To optimize their transparent conducting performance, we adjusted the Fe to F ratio to an atomic percentage of 0, 1, 2, and 3 at% during the film deposition. With the optimized Fe co-doping effect induced at Fe 2 at%, the resulting Fe-doped FTO films exhibited simultaneous improvements in the carrier concentration and Hall mobility which are, attributed to Vo induced by a Fe substitution, and the smooth surface morphology interfering with the growth of the FTO crystallites, respectively. As a result, the Fe-doped FTO films prepared at Fe 2 at% achieve a higher transparent conduction (4.4 ± 0.14 Ω/□ sheet resistance and 83.1% optical transmittance) than the other films with a figure of merit of 3.56 × 10−2 Ω−1. Hence, when these unique films are used in EC devices as a transparent conductive oxide, fast switching speeds (6.1 s coloration speed and 5.1 s bleaching speed) and a high coloration efficiency (CE) of 48.2 cm2/C occur as unique effects of the Fe-doped FTO films, accelerating the insertion of Li+ and electrons into the WO3 films, which act as an active EC material and enhancing the electrochemical activity. Therefore, our study provides promising insight into unique transparent conductive oxide films for high-performance EC devices.

Activated carbon has received enormous global attention as an electrode material for electrical double layer capacitors (EDLCs) due to its superior electrochemical performance. But while manufacturing high-quality activated carbon as an electrode material, overcoming limitations such as depletion of raw material resources, poor high-rate performance, and cycle stability is still a significant challenge. To address these limitations, we firstly suggest a novel mesoporous activated carbon derived from ecklonia cava (Meso-ACDE) using an acid-base reaction and KOH activation processes. The optimized Meso-ACDE electrode showed a superior specific capacitance of 182 F g−1 at the current density of 0.2 A g−1 and a high-rate capacitance of 154 F g−1 at the current density of 20.0 A g−1 with an excellent cycling stability up to 2000 cycles. The enhanced electrochemical performance of the Meso-ACDE electrode was mainly attributed to the well-developed mesoporous structure with a high concentration of oxygen related functional groups, which were acquired during the activation process. Thus, we believe that the Meso-ACDE could be a promising alternative to conventional activated carbon for high-performance EDLCs.

Photoelectrochemical (PEC) water splitting is a promising method for the conversion of solar energy into chemical energy stored in the form of hydrogen. Nanostructured hematite (α-Fe2 O3 ) is one of the most attractive materials for a highly efficient charge carrier generation and collection due to its large specific surface area and the short minority carrier diffusion length. In the present work, the PEC water splitting performance of nanostructured α-Fe2 O3 is investigated which was prepared by anodization followed by annealing in a low oxygen ambient (0.03 % O2 in Ar). It was found that low oxygen annealing can activate a significant PEC response of α-Fe2 O3 even at a low temperature of 400 °C and provide an excellent PEC performance compared with classic air annealing. The photocurrent of the α-Fe2 O3 annealed in the low oxygen at 1.5 V vs. RHE results as 0.5 mA cm-2 , being 20 times higher than that of annealing in air. The obtained results show that the α-Fe2 O3 annealed in low oxygen contains beneficial defects and promotes the transport of holes; it can be attributed to the improvement of conductivity due to the introduction of suitable oxygen vacancies in the α-Fe2 O3 . Additionally, we demonstrate the photocurrent of α-Fe2 O3 annealed in low oxygen ambient can be further enhanced by Zn-Co LDH, which is a co-catalyst of oxygen evolution reaction. This indicates low oxygen annealing generates a promising method to obtain an excellent PEC water splitting performance from α-Fe2 O3 photoanodes.

Carbon supports for dispersed platinum (Pt) electrocatalysts in direct methanol fuel cells (DMFCs) are being continuously developed to improve electrochemical performance and catalyst stability. However, carbon supports still require solutions to reduce costs and improve catalyst efficiency. In this study, we prepare well-dispersed Pt electrocatalysts by introducing titanium dioxide (TiO2) into biomass based nitrogen-doped carbon supports. In order to obtain optimized electrochemical performance, different amounts of TiO2 component are controlled by three types (Pt/TNC-2 wt%, Pt/TNC-4 wt%, and Pt/TNC-6 wt%). Especially, the anodic current density of Pt/TNC-4 wt% is 707.0 mA g−1 pt, which is about 1.65 times higher than that of commercial Pt/C (429.1 mA g−1 pt); Pt/TNC-4wt% also exhibits excellent catalytic stability, with a retention rate of 91 %. This novel support provides electrochemical performance improvement including several advantages of improved anodic current density and catalyst stability due to the well-dispersed Pt nanoparticles on the support by the introduction of TiO2 component and nitrogen doping in carbon. Therefore, Pt/TNC-4 wt% may be electrocatalyst a promising catalyst as an anode for high-performance DMFCs.

Photoelectrochemical (PEC) water splitting is a promising method for conversing solar energy into chemical energy stored in the form of hydrogen. Nanostructured hematite ($\alpha$-Fe$_2$O$_3$) is one of the most attractive materials for highly efficient charge carrier generation and collection due to its large specific surface area and shortening minority carrier diffusion length required to reach the surface. In the present work, PEC water splitting performance of $\alpha$-Fe$_2$O$_3$ prepared by anodization of thin iron layers on an FTO glass and subsequent annealing in low O$_2$-Ar ambient with only 0.03% O$_2$ was investigated. The key finding is that annealing the anodic nanostructures with low oxygen concentration provides a strongly enhanced PEC performance compared with classic air annealing. The photocurrent of the former at 1.5 V vs. RHE results in 1.1 mA/cm2, being 11 times higher than that of the latter. The enhancement of the PEC performance for $\alpha$-Fe$_2$O$_3$ annealed in low oxygen atmosphere can be attributed to controlled morphology, Sn doping, and introduction of oxygen vacancies, which contribute to the enhancement of the hole flux from the photogenerated site to the reactive surface and additionally lead to an enhanced hole transfer at the interface between the $\alpha$-Fe$_2$O$_3$ and the electrolyte. From the obtained results, it is evident that low oxygen annealing is a surprisingly effective method of defect engineering and optimizing $\alpha$-Fe$_2$O$_3$ electrodes for a maximized PEC water splitting performance.

Because of their excellent stability and highly specific surface area, carbon based materials have received attention as electrode materials of electrical double-layer capacitors(EDLCs). Biomass based carbon materials have been studied for electrode materials of EDLCs; these materials have low capacitance and high-rate performance. We fabricated tofu based porous activated carbon by polymer dissolution reaction and KOH activation. The activated porous carbon(APC-15), which has an optimum condition of 15 wt%, has a high specific surface area(1,296.1 m2 g−1), an increased average pore diameter(2.3194 nm), and a high mesopore distribution(32.4 %), as well as increased surface functional groups. In addition, APC has a high specific capacitance(195 F g−1) at low current density of 0.1 A g−1 and excellent specific capacitance(164 F g−1) at high current density of 2.0 A g−1. Due to the increased specific surface area, volume ratio of mesopores, and surface functional groups, the specific capacitance and high-rate performance increased. Consequently, the tofu based activated porous carbon can be proposed as an electrode material for high-performance EDLCs.

In recent years, advanced designs of non-precious electrocatalysts, such as those with transition metals and heteroatoms into iron‑nitrogen-doped mesoporous carbon, have been actively studied to replace precious-metal electrocatalysts for oxygen reduction reaction (ORR), which are used by future energy storage and conversion devices such as metal-air batteries and fuel cells. In the present study, we propose a noble non-precious electrocatalyst through the introduction of fluorine into iron‑nitrogen doped mesoporous carbon. To this end, we synthesized Tri(Fe/N/F)-doped mesoporous carbon nanofiber (MCNF) using electrospinning, the precursor coating method, and carbonization. Tri(Fe/N/F)-doped MCNFs exhibited an improved onset potential of ~0.9 V, the half-wave potential of ~0.82 V, and limiting-current density of −4.76 mA cm−1, with a four-electron pathway. In addition, Tri(Fe/N/F)-doped MCNFs showed remarkable long-term stability and endurance of methanol-crossover. Therefore, Tri(Fe/N/F)-doped MCNFs exhibited improved ORR performance, which could be explained by the increased specific surface area by mesoporous structures and improved oxygen adsorption by the synergy effects by Fe-Nx macrocycles and a high pyridinic- and pyrrolic-N species resulting from F doping.

With the increase in global challenges related to energy depletion, there is significant emphasis on studies involving next-generation optoelectronic applications such as smart windows and electronic displays. In particular, electrochromic devices (ECDs) have been identified as strategic innovations for energy-saving “smart windows” to address these challenges. Despite this increased level of attentions, ECDs have not yet attained broad commercial acceptance because of their limited electrochromic (EC) properties including coloration efficiency (CE, 10.0 s). To address these limitations, critical effort is required to enhance the EC properties by tuning the film structure and electronic structure of ECDs. In this study, we demonstrated the effect of nanocomposite structure of conductive metal oxides and WO3 EC films. Antimony-doped tin oxide nanoparticles (ATO NPs) were utilized because of their superior electrical conductivity and large band gap. To achieve the optimum addition amount of ATO NPs in EC films, we adjusted the amount as 0, 0.6, 1.2, 2.4 wt%. WO3 EC films with the optimum addition amount (1.2 wt%) of ATO NPs exhibited improved EC performance including both the switching speeds (5.4 s for the coloration speed and 2.4 s for the bleaching speed) and CE value (48.2 cm2/C). The enhancement of EC performance was attributed to the well-dispersed ATO NPs in the WO3 films that can effectively improve electrical conductivity via the formation of by forming preferred electron pathway. In addition, the large band gap of ATO NPs broadens the transmittance modulation of the EC layer which contributed to the increment of the CE value. Therefore, our results suggest a strategy to obtain the enhanced WO3 films with superior EC performances using conductive metal oxides nanocomposite structure.

As transparent conducting oxides (TCOs) have been widely used as a common component of many optoelectronic applications, ensuring high conductivity and transparency TCOs has become a pivotal concern. In the present study, we report developing the combustion-activated pyrolysis route of horizontal ultrasonic spray pyrolysis deposition (HUSPD) as a novel strategy to form highly transparent conducting fluorine-doped tin oxide (FTO) films. Compared to the basic route, the combustion-activated FTO films showed an attractive transparent conducting performance (figure of merit of 5.34 × 10−2 Ω−1) with a highly improved optical transparency (90.1%) due to the formation of a smooth and dense film structure to reduce light scattering on the surface, and a decrease of oxygen vacancies to broaden the optical bandgap, all of which yielded an excellent performance as compared to the previously reported studies on the FTO films. Moreover, when the combustion-activated FTO films were used as TCOs of electrochromic devices and dye-sensitized solar cells, they acquired multifunctional effects of (a) an efficient electron transfer by (200) preferred orientations of the FTO; (b) a relaxed light scattering on the interface due to smooth and dense surface morphology of the FTO films; and (c) a broad optical bandgap by decreased oxygen vacancies, resulting in an impressive improvement of both electrochromic and photovoltaic performances. Taken together, our results demonstrate that combustion-activated FTO films are an attractive technique for forming high-performance TCOs that can further be used in multifunctional optoelectronic devices.

In the present study, V2O5 nanorod (VR)/graphene oxide (GO) nanocomposite films that can be used as an electrochromic (EC) material have been developed using the sol-gel spin-coating method. In order to optimize the nanocomposite effect of GO consisting of the VR films on EC performances, we controlled the volume percentage of GO compared to vanadium precursor to 0, 1, 2, and 3 vol%. With the increase of GO in VR films to 2 vol%, the resultant films exhibited a densely percolated structure, which was due to the nanocomposite effect of GO to generate the VR growth by an interaction with the oxygen-containing functional groups of GO. Due to the effect of optimized GO, the VR/GO nanocomposite films fabricated with 2 vol% GO revealed fast switching speeds (2.5 s for the bleaching speed and 1.4 s for the colouration speed). This was the result of an improved electrical conductivity and ion diffusion coefficient and high cycling retention of transmittance modulation (94.90% after 500 cycles) stemming from the remarkable electrochemical stability of the films as compared to those of bare VR films.

Providing a crystallographic and electronic modification of carbon-based materials in electrical double-layer capacitors (EDLCs) is an essential technology needed to improve the charge storage kinetics and to enhance ultrafast cycling performances. However, despite numerous structural composite and morphological modification efforts focused on active materials, ultrafast charge storage kinetics still indicated a poor ultrafast capacitance and low cycling stability. To solve these problems, in the present study, we propose a novel heteroatom (N, P, and B)-doped activated carbon (AC) that has the synergistic effects of N-, P-, and B-doping using the one-pot doping calcination process. Compared to the bare-AC, N-doped AC, P-doped AC, and B-doped AC, the novel heteroatom-doped AC indicates an improved ultrafast charge storage kinetics, such as high specific capacitance (243.9 F g−1 at the scan rate of 10 mV s−1), good cycling stability (216.7 F g−1 at 100 mV s−1 after 500 cycles), and superb ultrafast cycling capacitance (199.7 F g−1 at 300 mV s−1). These superb electrochemical performances can be attributed by synergistic effects of increased active sites by N-doping related to a high charge storage area, improved functional groups by P-doping related to an excellent wettability between the electrode and the electrolyte, and enhanced electrical properties by B-doping related to a good electron acceptability.

Due to its high electrical conductivity and excellent chemical/physical durability, the nickel (Ni) foam is conventionally used as the current collector of supercapacitors that are characterised by high power density, rapid charge/discharge cycles, and long lifespan. However, the limitation of the current collector is its flat surface, which leads to a low rate performance and cycling stability. Therefore, a rational design of the current collector and the electrode material is an essential interfacial engineering technology to be developed to improve the electrochemical performance of the collector. In the present study, applying the surface functionalization of the Ni current collector with the nano-sized stairs of the terraced surface resulted in the electrochemical performance of a remarkable capacitance (210 F g−1 at the current density of 0.5 A g−1), excellent rate performance of 83%, and outstanding cycling stability of 89% after 10,000 cycles. The proposed design has obvious advantages in terms of the high contact area between the current collector and electrode material, on the one hand, and the uneven surface, one the other hand, leading to an excellent rate performance and an outstanding cycling stability. This remarkable capability demonstrates that the surface functionalization of the current collector is a promising technology for high-performance supercapacitors.

In the present study, vanadium oxide(V2O5) films for electrochromic(EC) application are fabricated using sol-gel spin coating method. In order to optimize the EC performance of the V2O5 films, we adjust the amounts of polyvinylpyrrolidone(PVP) added to the solution at 0, 5, 10, and 15 wt%. Due to the effect of added PVP on the V2O5 films, the obtained films show increases of film thickness and crystallinity. Compared to other samples, optimum weight percent(10 wt%) of PVP led to superior EC performance with transmittance modulation(45.43 %), responding speeds(6.0 s at colored state and 6.2 s at bleached state), and coloration efficiency(29.8 cm2/C). This performance improvement can be mainly attributed to the enhanced electrical conductivity and electrochemical activity due to the increased crystallinity and thickness of the V2O5 films. Therefore, V2O5 films fabricated with optimized amount of PVP can be a promising EC material for high-performance EC devices.

Nb-doped TiO2(NTO) coated NiCrAl alloy foam for hydrogen production is prepared using ultrasonic spray pyrolysis deposition(USPD) method. To optimize the size and distribution of NTO particles based on good physical and chemical stability, we synthesize particles by adjusting the weight ratio of the Nb precursor solution(5 wt%, 10 wt% and 15 wt%). The morphological, chemical bonding, and structural properties of the NTO coated NiCrAl alloy foam are investigated by X-ray diffraction(XRD), X-ray photo-electron spectroscopy(XPS), and Field-Emission Scanning Electron Microscopy(FESEM). As a result, the samples of controlled Nb weight ratio exhibit a common diffraction pattern at ~25.3o , corresponding to the(101) plane, and have chemical bonding(O-Nb=O) at 534 eV. The NTO particles with the optimum weight ratio of N (10 wt%) show a uniform distribution with a size of ~18.2-21.0 nm. In addition, they exhibit the highest corrosion resistance even in the electrochemical stability estimation. As a result, the introduction of NTO coated NiCrAl alloy foam by USPD improves the chemical stability of the NiCrAl alloy foam by protecting the direct electrochemical reaction between the foam and the electrolyte. Thus, the optimized NTO coating can be proposed for excellent protection of NiCrAl alloy foam for hydrocarbon-based steam methane reforming(SMR).

The ability to provide a reasonable design and a practical modification of the interfacial structure in lithium-ion batteries (LIBs) is a key technology to enhance electrochemical kinetics and to improve ultrafast cycling performances. However, in recent years, despite considerable structural engineering efforts focused on active materials, in practice, ultrafast LIB performances still are characterized by low ultrafast cycling capacity and poor stability at the current density above 6 C. To solve these problems, in the present study, we propose a unique interface modification of the Al foil having crater porous interface using the electrochemical etching process. The cathode fabricated with a crater porous interface of the Al foil exhibits a remarkably enhanced ultrafast storage performance, such as high ultrafast cycling capacity (91.0 mAh g−1 at 10 C) and superb ultrafast cycling stability (76.2 mAh g−1 with the capacity retention of 84.8% at 10 C after 250 cycles) as compared to those of the cathode fabricated with the bare Al foil and commercial-etched Al foil. These improved electrochemical performances can be explained by the combined effects of improved electrical conductivity related to fast charge transport and increased interface contact area between the active material and the current collector related to enhanced interface adhesion during ultrafast cycling performance.

Characterized by high power density and long cycle life, electric double layer capacitors have been considered to be most promising energy storage devices. However, the use of low electrolyte concentration due to the degradation of current collector in high electrolyte concentration involves their limitation for ionic diffusion at high current densities during cycling, leading to a low electrochemical behavior. Therefore, the sensible design of the interfacial structure between the current collector and the active material is a supreme technology for accomplishing desired requirements as the improved performance of current collector. In the present paper, by applying the graphite nanosheet as an interlayer on the nickel (Ni) current collector, the electrochemical performance is improved with high specific capacitance (236 F g−1 at the current density of 0.2 A g−1), outstanding high-rate ability (87%), and excellent cycling stability (93% after 10,000 cycles in the high-concentration electrolyte). Hence, the advantages of this unique approach include the improvement of the contact area between the current collector and the active material and prevention of the oxidation of the Ni current collector. This enhanced electrochemical performance suggests that this interface engineering is a powerful strategy for potential applications in electric double layer capacitors.

In the present study, Fe-doped V2O5 films showing impressive electrochromic (EC) performance were developed using the sol-gel spin-coating method. To confirm the optimized Fe-doping effect on the V2O5 films for the EC performance, we adjusted the Fe atomic percentages to 0.0, 0.5, 1.0, and 1.5 at%, respectively. With the effect of Fe doping on the V2O5 films, the obtained films resulted in the formation of the oxygen vacancies. As the result, when the optimum Fe atomic percentage was 1.0 at%, the enhanced switching speeds (3.7 s for the bleaching speed and 2.0 s for the coloration speed) and enhanced coloration efficiency value (47.3 cm2/C) compared to the other films were implemented. This can be attributed to the improved electrical conductivity and Li+ diffusion coefficient that led to efficient generation of the EC reaction activity and narrowing the optical bandgap at the coloration state to increase transmittance modulation. Therefore, this unique film can be a promising EC material to improve the performance for the EC devices.

Due to their excellent chemical stability, as well as low operating temperature, high energy density, and environment-friendliness, carbon supports are a prospective candidate for platinum (Pt) nanocatalysts in direct methanol fuel cells (DMFCs). However, numerous efforts to achieve the high efficiency for the energy conversion by carbon supports have faced considerable challenges owing to an inefficient utilization of the inside region, leading to the low electrochemical performance. Thus, in the present study, we propose an advanced surface technology for the mesoporous structure. The obtained Pt nanocatalyst-decorated mesoporous carbon nanofiber support offers a high anodic current density of 732 mA mgPt−1, and an excellent catalytic stability as compared to the commercial Pt/C (20 wt% Pt on Vulcan carbon, De Nora S.P.A.) and Pt/CNF. Due to these characteristics, this advanced carbon support provides several, benefits such as the well-dispersed Pt nanocatalysts on the surface, as well as achieves a superb catalytic stability. In sum, the advanced carbon support is a promising candidate to improve the electrochemical performance of DMFCs.

Background This study was conducted to explore the effect of known risk factors, focusing on risk factors including age at menarche, age at menopause, number of children, family history of breast cancer, and age at first birth according to breast density, in consideration of interaction among East-Asian women. Methods Case-control study with 2,123 cases and 2,121 controls with mammographic density was conducted. Using the mammographic film, breast density was measured using Breast Imaging-Reporting and Data System. To identify the association of selected reproductive factors including age at menarche, age at menopause, number of children, family history of breast cancer, and age at first birth according to breast density, stratified analysis was conducted according to breast density groups and interaction effects was assessed. The results were presented with adjusted OR and 95% CIs. Results Significant interaction effect between age at first birth and breast density on breast cancer (P = 0.048) was observed. Women with age at first birth ≥ 28 years old showed increased breast cancer risk in extremely dense breast group (≥ 75%) (OR = 1.627, 95% CI = 1.190-2.226). However, women with fatty breast (< 50%) and heterogeneously dense breast (50%-75%) did not show an increased association. Age at menarche, age at menopause, number of children, and family history of breast cancer did not show significant interaction with breast cancer and similar risk patterns were observed. Conclusions Age at first birth showed significant interaction with breast density on breast cancer risk. Further studies considering biologically plausable model between exposure, intermediate outcomes and breast cancer risk with prospective design need to be undertaken in East Asian women.