A bismuth vanadate(BiVO4)photoanode with a cocatalyst consisting of NiFe layered double‐hydroxide(NiFe‐LDH)nanoparticles was fabricated for photoelectrochemical(PEC)water splitting.NiFe‐LDH nanoparticles,which can ...A bismuth vanadate(BiVO4)photoanode with a cocatalyst consisting of NiFe layered double‐hydroxide(NiFe‐LDH)nanoparticles was fabricated for photoelectrochemical(PEC)water splitting.NiFe‐LDH nanoparticles,which can improve light‐absorption capacities and facilitate efficient hole transfer to the surface,were deposited on the surface of the BiVO4 photoanode by a hydrothermal method.All the samples were characterized using X‐ray diffraction,scanning electron microscopy,and diffuse‐reflectance spectroscopy.Linear sweep voltammetry and current‐time plots were used to investigate the PEC activity.The photocurrent response of NiFe‐LDH/BiVO4 at 1.23 V vs the reversible hydrogen electrode was higher than those of Ni(OH)2/BiVO4,Fe(OH)2/BiVO4 and pure BiVO4 electrodes under visible‐light illumination.NiFe‐LDH/BiVO4 also gave a superior PEC hydrogen evolution performance.Furthermore,the stability of the NiFe‐LDH/BiVO4 photoanode was excellent compared with that of the bare BiVO4 photoanode,and offers a novel method for solar‐assisted water splitting.展开更多
In this work, the results on the investigation of the precularity near the solar spectrum region, of Zn1.xCdxSe nanofilms, nanoscale heterojunction prepared on silikon and alumminium substrates by precipitation from a...In this work, the results on the investigation of the precularity near the solar spectrum region, of Zn1.xCdxSe nanofilms, nanoscale heterojunction prepared on silikon and alumminium substrates by precipitation from aqueous solutions are presented. The temperature dependence of dark and light conductivity, spectrum and optical quenching of primary and impurity photoconductivity are investigated. The obtained results show that when controlling ionic composition and HT (heat-treatment) conditions, one can purposely control the properties of Zn1-xCdxSe (0 ≤ x ≤ 0.6) films, achieve the appropriate degree of compensation of different recombination levels and traps attributed to intrinsic defects or impurities, which result in high level of photoelectrical parameters near the IR region. Just after deposition the photoconductivity spectrum maximum of Zn1-xCdxSe (0 〈 x 〈 0.6) films is observed at λ1 = 0.545 + 0.495/am versus the film composition.展开更多
Based on the experimental results of Chen et al. to use the solar furnace and medium frequency induction furnace to extract boron impurity from metallurgical silicon, we propose a strong radiation catalysis mechanism ...Based on the experimental results of Chen et al. to use the solar furnace and medium frequency induction furnace to extract boron impurity from metallurgical silicon, we propose a strong radiation catalysis mechanism to explain the difference of reaction rates in these two furnaces. The postulate assuming the photons striking on the material not only increase the thermal energy of the molecules of reactants but also lower down the energy barrier of the reaction to speed up the chemical reaction. It is believed the photon catalysis mechanism is unlversall in most of high temperature chemical reactions and looking forward to more evidences for the postulate proposed in this article.展开更多
Quaternary chalcogenide Cu2FeSnS4 (CFTS) nanoparticles, as a kind of potential absorber layer material in thin film solar cells (TFSCs), were successfully synthesized by using a convenient solvothermal method. Alk...Quaternary chalcogenide Cu2FeSnS4 (CFTS) nanoparticles, as a kind of potential absorber layer material in thin film solar cells (TFSCs), were successfully synthesized by using a convenient solvothermal method. Alkali element K is incorporated into CFTS thin films in order to fiLrther improve the surface morphology and the optical properties of related films. X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM) were used to characterize the phase purity, morphology and composition of CFTS particles and thin films. The results show that the particle elemental ratios of Cu/(Fe+Sn) and Fe/Sn are 1.2 and 0.9, respectively, which are close to the characteristics of stoichiometric CFTS. The band gaps of CFTS films before and after doping K ions are estimated to be 1.44 eV and 1.4 eV with an error of ±0.02 eV.展开更多
We report here our results on the investigation of the chain dynamics of poly(acrylic acid) in aqueous solution. The concentration of poly(acrylic acid) was approximately 3.8×10^(-4) mol/L, two orders of magnitud...We report here our results on the investigation of the chain dynamics of poly(acrylic acid) in aqueous solution. The concentration of poly(acrylic acid) was approximately 3.8×10^(-4) mol/L, two orders of magnitude higher than that reported in the literature. The p H value of the solution was 3.9, and the hydrogen bonds between the intrinsic and ionized carboxylic acid groups formed dynamic networks, which captured aggregation-induced emission-active molecules(a tetra-quaternary ammonium modified tetraphenylethene derivative) inside the polymer coils and induced fluorescence emission. The hydrogen bonds can be classified as intra- or intermolecular; both can be probed based on the emission change of the tetra-quaternary ammonium modified tetraphenylethene probes. The effects of different external stimuli on the polymer chain dynamics were investigated using different metal cations(including Na^+, Li^+, Zn^(2+), Ni^(2+), Ca^(2+), and Co^(2+)), different cation concentrations(1×10^(-6) to 4×10^(-4) mol/L), different poly(acrylic acid) molecular weights(5, 240, and 450 k Da), and different copolymers. The experimental results indicate that the long poly(acrylic acid) chains(high molecular weight) tend to form dense globular coils and exclude the probe molecules outside, which are robust and unsusceptible to water-soluble metal cations. However, the shorter poly(acrylic acid) chains tend to form intermolecular hydrogen bonds, which are helpful in capturing more probe molecules inside the networks, thus inducing stronger emission. Because of the dual functions of forming hydrogen bonds with carboxylic groups and acting as an acceptor of protons from the carboxylic acid group to form cationic species, copolymerization with acrylate amide [poly(acrylic acid)-co-poly(acrylamide)] can greatly affect the chain dynamics of poly(acrylic acid) segments, which is reflected by the drastically decreased emission intensity from the fluorescent probes.展开更多
Large-scale single crystals have potential applications in many fields,such as in ferroelectric and photoelectric energy conversion devices.Perovskite oxynitrides have also attracted attention in photoelectrochemical ...Large-scale single crystals have potential applications in many fields,such as in ferroelectric and photoelectric energy conversion devices.Perovskite oxynitrides have also attracted attention in photoelectrochemical water splitting systems because of their high theoretical solar-to-hydrogen efficiencies.Nevertheless,the synthesis of perovskite oxynitride single crystals requires the coupling of cation exchange and ammonization processes,which is exceptionally challenging.The present study demonstrates an inorganic vapor method that provides,for the first time ever,high-quality epitaxial perovskite SrTaO_(2)N single crystals on the centimeter scale.Assessments using Raman spectroscopy,crystal structure analysis and density functional theory determined that the conversion mechanism followed a topotactic transition mode.Compared with conventional SrTaO_(2)N particle-assembled films,the SrTaO_(2)N single crystals made in this work were free of interparticle interfaces and grain boundaries,which exhibited extremely high performance during photoelectrochemical water oxidation.In particular,these SrTaO_(2)N single crystals showed the highest photocurrent density at 0.6 V vs.RHE(1.20 mA cm^(−2)) and the highest photocurrent filling factor(47.6%)reported to date,together with a low onset potential(0.35 V vs.RHE).This onset potential was 200 mV less than that of the reported in situ SrTaO_(2)N film,and the photocurrent fill factor was improved by 2 to 3 times.展开更多
基金supported by the National Natural Science Foundation of China(21663027,51262028,21261021)the Science and Technology Support Project of Gansu Province(1504GKCA027)+2 种基金the Program for the Young Innovative Talents of Longyuanthe Program for Innovative Research Team(NWNULKQN-15-2)the Undergraduate Academic Innovative Research Team of Northwest Normal University~~
文摘A bismuth vanadate(BiVO4)photoanode with a cocatalyst consisting of NiFe layered double‐hydroxide(NiFe‐LDH)nanoparticles was fabricated for photoelectrochemical(PEC)water splitting.NiFe‐LDH nanoparticles,which can improve light‐absorption capacities and facilitate efficient hole transfer to the surface,were deposited on the surface of the BiVO4 photoanode by a hydrothermal method.All the samples were characterized using X‐ray diffraction,scanning electron microscopy,and diffuse‐reflectance spectroscopy.Linear sweep voltammetry and current‐time plots were used to investigate the PEC activity.The photocurrent response of NiFe‐LDH/BiVO4 at 1.23 V vs the reversible hydrogen electrode was higher than those of Ni(OH)2/BiVO4,Fe(OH)2/BiVO4 and pure BiVO4 electrodes under visible‐light illumination.NiFe‐LDH/BiVO4 also gave a superior PEC hydrogen evolution performance.Furthermore,the stability of the NiFe‐LDH/BiVO4 photoanode was excellent compared with that of the bare BiVO4 photoanode,and offers a novel method for solar‐assisted water splitting.
文摘In this work, the results on the investigation of the precularity near the solar spectrum region, of Zn1.xCdxSe nanofilms, nanoscale heterojunction prepared on silikon and alumminium substrates by precipitation from aqueous solutions are presented. The temperature dependence of dark and light conductivity, spectrum and optical quenching of primary and impurity photoconductivity are investigated. The obtained results show that when controlling ionic composition and HT (heat-treatment) conditions, one can purposely control the properties of Zn1-xCdxSe (0 ≤ x ≤ 0.6) films, achieve the appropriate degree of compensation of different recombination levels and traps attributed to intrinsic defects or impurities, which result in high level of photoelectrical parameters near the IR region. Just after deposition the photoconductivity spectrum maximum of Zn1-xCdxSe (0 〈 x 〈 0.6) films is observed at λ1 = 0.545 + 0.495/am versus the film composition.
文摘Based on the experimental results of Chen et al. to use the solar furnace and medium frequency induction furnace to extract boron impurity from metallurgical silicon, we propose a strong radiation catalysis mechanism to explain the difference of reaction rates in these two furnaces. The postulate assuming the photons striking on the material not only increase the thermal energy of the molecules of reactants but also lower down the energy barrier of the reaction to speed up the chemical reaction. It is believed the photon catalysis mechanism is unlversall in most of high temperature chemical reactions and looking forward to more evidences for the postulate proposed in this article.
基金supported by National Natural Science Foundation of China(No.51674026)the Fundamental Research Funds for the Central Universities in 2015(No.FRF-BD-15-004A)
文摘Quaternary chalcogenide Cu2FeSnS4 (CFTS) nanoparticles, as a kind of potential absorber layer material in thin film solar cells (TFSCs), were successfully synthesized by using a convenient solvothermal method. Alkali element K is incorporated into CFTS thin films in order to fiLrther improve the surface morphology and the optical properties of related films. X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM) were used to characterize the phase purity, morphology and composition of CFTS particles and thin films. The results show that the particle elemental ratios of Cu/(Fe+Sn) and Fe/Sn are 1.2 and 0.9, respectively, which are close to the characteristics of stoichiometric CFTS. The band gaps of CFTS films before and after doping K ions are estimated to be 1.44 eV and 1.4 eV with an error of ±0.02 eV.
基金supported by the Natural Science Foundation of Zhejiang Province(2012C32007Z4110056)the National Basic Research Program of China(2013CB834704)
文摘We report here our results on the investigation of the chain dynamics of poly(acrylic acid) in aqueous solution. The concentration of poly(acrylic acid) was approximately 3.8×10^(-4) mol/L, two orders of magnitude higher than that reported in the literature. The p H value of the solution was 3.9, and the hydrogen bonds between the intrinsic and ionized carboxylic acid groups formed dynamic networks, which captured aggregation-induced emission-active molecules(a tetra-quaternary ammonium modified tetraphenylethene derivative) inside the polymer coils and induced fluorescence emission. The hydrogen bonds can be classified as intra- or intermolecular; both can be probed based on the emission change of the tetra-quaternary ammonium modified tetraphenylethene probes. The effects of different external stimuli on the polymer chain dynamics were investigated using different metal cations(including Na^+, Li^+, Zn^(2+), Ni^(2+), Ca^(2+), and Co^(2+)), different cation concentrations(1×10^(-6) to 4×10^(-4) mol/L), different poly(acrylic acid) molecular weights(5, 240, and 450 k Da), and different copolymers. The experimental results indicate that the long poly(acrylic acid) chains(high molecular weight) tend to form dense globular coils and exclude the probe molecules outside, which are robust and unsusceptible to water-soluble metal cations. However, the shorter poly(acrylic acid) chains tend to form intermolecular hydrogen bonds, which are helpful in capturing more probe molecules inside the networks, thus inducing stronger emission. Because of the dual functions of forming hydrogen bonds with carboxylic groups and acting as an acceptor of protons from the carboxylic acid group to form cationic species, copolymerization with acrylate amide [poly(acrylic acid)-co-poly(acrylamide)] can greatly affect the chain dynamics of poly(acrylic acid) segments, which is reflected by the drastically decreased emission intensity from the fluorescent probes.
基金supported by the National Key Research and Development Program of China(2018YFA0209303)the National Natural Science Foundation of China(22025202 and 51972165)Natural Science Foundation of Jiangsu Province(BK20202003)。
文摘Large-scale single crystals have potential applications in many fields,such as in ferroelectric and photoelectric energy conversion devices.Perovskite oxynitrides have also attracted attention in photoelectrochemical water splitting systems because of their high theoretical solar-to-hydrogen efficiencies.Nevertheless,the synthesis of perovskite oxynitride single crystals requires the coupling of cation exchange and ammonization processes,which is exceptionally challenging.The present study demonstrates an inorganic vapor method that provides,for the first time ever,high-quality epitaxial perovskite SrTaO_(2)N single crystals on the centimeter scale.Assessments using Raman spectroscopy,crystal structure analysis and density functional theory determined that the conversion mechanism followed a topotactic transition mode.Compared with conventional SrTaO_(2)N particle-assembled films,the SrTaO_(2)N single crystals made in this work were free of interparticle interfaces and grain boundaries,which exhibited extremely high performance during photoelectrochemical water oxidation.In particular,these SrTaO_(2)N single crystals showed the highest photocurrent density at 0.6 V vs.RHE(1.20 mA cm^(−2)) and the highest photocurrent filling factor(47.6%)reported to date,together with a low onset potential(0.35 V vs.RHE).This onset potential was 200 mV less than that of the reported in situ SrTaO_(2)N film,and the photocurrent fill factor was improved by 2 to 3 times.