Quantum-sized CdS-coated TiO2 nanotube array （Q-CdS-TiO2 NTA） was fabricated by the modified successive ionic layer absorption and reaction method. Scanning electron microscope and transmission electron microscope i...Quantum-sized CdS-coated TiO2 nanotube array （Q-CdS-TiO2 NTA） was fabricated by the modified successive ionic layer absorption and reaction method. Scanning electron microscope and transmission electron microscope images showed the regular structure of TiO2 NTA, where quantum-sized CdS （diameter 〈10nm） deposited on both the inside and outside of TiO2 nanotube wall. Fabrication conditions including immersing cycles, calcination temperature and drying process were well optimized, and the Q-CdS-TiO2 NTA and its photoelectrochemical （PEC） properties were characterized by X-ray fluorescence spectrometer, UV-Vis diffuse reflectance spectra and photovoltage. Distinct increases in visible light absorption and photocurrent were observed as the immersing cycle was increased from 5 to 20 times. The additional drying process accelerated the CdS crystal growth rate, and thus, the fabrication time could be shortened accordingly. Calcination temperature influenced the PEC property of Q-CdS-TiO2 NTA deeply, and the optimized calcination temperature was found as 500 ℃. As the Q-CdS-TiO2 NTA was fabricated under such condition, the visible photocurrent density increased to 2.8 mA/cm and the photovoltage between 350 and 480 nm was enhanced by 2.33 times than that without calcination. This study is expected to optimize Q-CdS-TiO2 NTA fabrication conditions for the purpose of improving its PEC performance.展开更多
The severe bulk recombination and sluggish oxygen evolution reaction(OER)dynamics of photoanodes severely restrict the application of photoelectrochemical(PEC)devices.To solve these two problems,crystallographic facet...The severe bulk recombination and sluggish oxygen evolution reaction(OER)dynamics of photoanodes severely restrict the application of photoelectrochemical(PEC)devices.To solve these two problems,crystallographic facet orientation and cocatalyst emergence with a high-quality photoanode/cocatalyst interface were realized through an air annealing-assisted strategy to treat atomic layer deposition(ALD)-modified SnSnanosheet arrays.Based on experimental observations and theoretical calculations,the reduced(001)crystal facet of SnSdecreases the recombination of photogenerated carriers in the bulk and improves the carrier separation of the photoanode.Moreover,the unexpectedly formed ZnTiOSfilm decreases the overpotential of the surface OER,reduces interface recombination,and extends the carrier lifetime.These synergistic effects lead to significantly enhanced PEC performance,with a high photocurrent density of 1.97 mA cm^(-2)at 1.23 V vs.reversible hydrogen electrode(RHE)and a low onset potential of 0.21 V vs.RHE,which are superior to reported mostly SnS-based photoanodes.展开更多
Water-soluble gelatin-PbS bionanocomposites （BNCs） were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy （TEM）, X-ray diffrac...Water-soluble gelatin-PbS bionanocomposites （BNCs） were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, UV-vis absorption spectra （UV-vis）, Fourier transform infrared spectra （FT-IR） and circular dichroism （CD）. FT-IR data were used to envis- age the binding of PbS particles with oxygen atoms of carbonyl groups of gelatin molecule. The possible integration mechanism between gelatin and PbS was discussed in detail. The effect of Pb2＋ and PbS on the conformations of gelatin has also been analyzed by means of UV-vis, CD and FT-IR spectra, resulting in less c^-helix content and more open structures （[3-sheet, r-turn, or expanded）. A new formula to calculate the association constant was proposed according to the relationship between the absorbance of gelatin-PbS BNCs and the free concentration of PbS, and apparent association constants K （298/303/308 K： 3.11/2.00/1.60 × 10^6 tool/L） at three different temperatures were calculated based on this formula. Thermodynamic parameters such as AG^θ, △Hθ and △S^θ were also determined. The results of the thermodynamic investigations indicated that the reaction was spontaneous （AG^θ 〈 0）, and enthalpy-driven （△H^8 〈 0）.展开更多
基金supported by the National Natural Science Foundation of China(21377020)the Fundamental Research Funds for the Central Universities(DUT15QY17)
文摘Quantum-sized CdS-coated TiO2 nanotube array （Q-CdS-TiO2 NTA） was fabricated by the modified successive ionic layer absorption and reaction method. Scanning electron microscope and transmission electron microscope images showed the regular structure of TiO2 NTA, where quantum-sized CdS （diameter 〈10nm） deposited on both the inside and outside of TiO2 nanotube wall. Fabrication conditions including immersing cycles, calcination temperature and drying process were well optimized, and the Q-CdS-TiO2 NTA and its photoelectrochemical （PEC） properties were characterized by X-ray fluorescence spectrometer, UV-Vis diffuse reflectance spectra and photovoltage. Distinct increases in visible light absorption and photocurrent were observed as the immersing cycle was increased from 5 to 20 times. The additional drying process accelerated the CdS crystal growth rate, and thus, the fabrication time could be shortened accordingly. Calcination temperature influenced the PEC property of Q-CdS-TiO2 NTA deeply, and the optimized calcination temperature was found as 500 ℃. As the Q-CdS-TiO2 NTA was fabricated under such condition, the visible photocurrent density increased to 2.8 mA/cm and the photovoltage between 350 and 480 nm was enhanced by 2.33 times than that without calcination. This study is expected to optimize Q-CdS-TiO2 NTA fabrication conditions for the purpose of improving its PEC performance.
基金support from the National Key Research and Development Program of China(2021YFA1500800)the National Natural Science Foundation of China(52025028)+1 种基金the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutionssupport of the National Natural Science Foundation of China(21973006)。
文摘The severe bulk recombination and sluggish oxygen evolution reaction(OER)dynamics of photoanodes severely restrict the application of photoelectrochemical(PEC)devices.To solve these two problems,crystallographic facet orientation and cocatalyst emergence with a high-quality photoanode/cocatalyst interface were realized through an air annealing-assisted strategy to treat atomic layer deposition(ALD)-modified SnSnanosheet arrays.Based on experimental observations and theoretical calculations,the reduced(001)crystal facet of SnSdecreases the recombination of photogenerated carriers in the bulk and improves the carrier separation of the photoanode.Moreover,the unexpectedly formed ZnTiOSfilm decreases the overpotential of the surface OER,reduces interface recombination,and extends the carrier lifetime.These synergistic effects lead to significantly enhanced PEC performance,with a high photocurrent density of 1.97 mA cm^(-2)at 1.23 V vs.reversible hydrogen electrode(RHE)and a low onset potential of 0.21 V vs.RHE,which are superior to reported mostly SnS-based photoanodes.
基金supported by the National Natural Science Foundation of China(21067001)Natural Science Foundation of Guangxi Province(0991083)Innovation Project of Guangxi University for Nationalities(gxun-chx2012091)
文摘Water-soluble gelatin-PbS bionanocomposites （BNCs） were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, UV-vis absorption spectra （UV-vis）, Fourier transform infrared spectra （FT-IR） and circular dichroism （CD）. FT-IR data were used to envis- age the binding of PbS particles with oxygen atoms of carbonyl groups of gelatin molecule. The possible integration mechanism between gelatin and PbS was discussed in detail. The effect of Pb2＋ and PbS on the conformations of gelatin has also been analyzed by means of UV-vis, CD and FT-IR spectra, resulting in less c^-helix content and more open structures （[3-sheet, r-turn, or expanded）. A new formula to calculate the association constant was proposed according to the relationship between the absorbance of gelatin-PbS BNCs and the free concentration of PbS, and apparent association constants K （298/303/308 K： 3.11/2.00/1.60 × 10^6 tool/L） at three different temperatures were calculated based on this formula. Thermodynamic parameters such as AG^θ, △Hθ and △S^θ were also determined. The results of the thermodynamic investigations indicated that the reaction was spontaneous （AG^θ 〈 0）, and enthalpy-driven （△H^8 〈 0）.
