The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS...The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS QDs and hollow nanotube In_(2)O_(3)is successfully achieved using an electrostatic self-assembly method.Under visible light irradiation,all CdS-In_(2)O_(3)composites exhibit higher hydrogen evolution efficiency compared to pure CdS QDs.Notably,the photocatalytic H_(2)evolution rate of the optimal CdS-7%In_(2)O_(3)composite is determined to be 2258.59μmol g^(−1)h^(−1),approximately 12.3 times higher than that of pure CdS.The cyclic test indicates that the CdS-In_(2)O_(3)composite maintains considerable activity even after 5 cycles,indicating its excellent stability.In situ X-ray photoelectron spectroscopy and density functional theory calculations confirm that carrier migration in CdS-In_(2)O_(3)composites adheres to a typical S-scheme heterojunction mechanism.Additionally,a series of characterizations demonstrate that the formation of S-scheme heterojunctions between In_(2)O_(3)and CdS inhibits charge recombination and accelerates the separation and migration of photogenerated carriers in the CdS QDs,thus achieving enhanced photocatalytic performance.This work elucidates the pivotal role of S-scheme heterojunctions in photocatalytic H_(2)production and offers novel insights into the construction of effective composite photocatalysts.展开更多
This study describes the adsorption features of cadmium on Fe2O3 and MnO2 in alkaline saline conditions. The adsorption reached equilibrium in 6 hours under alkaline conditions. The absorption of cadmium on Fe2O3 and ...This study describes the adsorption features of cadmium on Fe2O3 and MnO2 in alkaline saline conditions. The adsorption reached equilibrium in 6 hours under alkaline conditions. The absorption of cadmium on Fe2O3 and MnO2 was consistent with Freundlich absorption isotherms, and the corresponding adsorption capacities were 16.3 and 16.7 mg·g-1, respectively. Moreover, the adsorption quantity of cadmium on Fe2O3 and MnO2 rose with increas-ing pH from acidic to neutral, and reached the maximum at pH= 9. The coexisting chlorides reduced the adsorption capacity of Fe2O3 and MnO2. The influence intensities of different cations follow the order of CaCl2>>KCl>NaCl. However, the influence of sodium salts on the capacities of Fe2O3 and MnO2 to adsorb cadmium appeared more complicated: the relatively low concentrations of sodium salts could reduce the adsorption capacity; with increasing concentrations of sodium salts, e.g. NaCl and NaNO3. the adsorption capacity decreased continually. Moreover, due to the competition adsorption and precipitation effects, the adsorption capabilities of Na2CO3, NaH2PO4 and Na2HSO4 could also be reduced and cadmium concentrations in the solution were reduced as well.展开更多
Noble metal-loaded layered hydroxides exhibit high efficiency in electrocatalyzing water splitting.However,their widespread use as bifunctional electrocatalysts is hindered by low metal loading,inefficient yield,and c...Noble metal-loaded layered hydroxides exhibit high efficiency in electrocatalyzing water splitting.However,their widespread use as bifunctional electrocatalysts is hindered by low metal loading,inefficient yield,and complex synthesis processes.In this work,platinum atoms were anchored onto nickel-iron layered double hydroxide/carbon nanotube(LDH/CNT)hybrid electrocatalysts by using a straightforward milling technique with K_(2)Pt Cl_(6)·6H_(2)O as the Pt source.By adjusting the Pt-to-Fe ratio to 1/2 and 1/10,excellent electrocatalysts—Pt_(1/6)-Ni_(2/3)Fe_(1/3)-LDH/CNT and Pt_(1/30)-Ni_(2/3)Fe_(1/3)-LDH/CNT—were achieved with superior performance in hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),outperforming the corresponding commercial Pt/C(20 wt%)and Ru O_(2)electrocatalysts.The enhanced electrochemical performance is attributed to the modification of Pt's electronic structure,which exhibits electron-rich states for HER and electrondeficient states for OER,significantly boosting Pt's electrochemical activity.Furthermore,the simple milling technology for controlling Pt loading offers a promising approach for scaling up the production of electrocatalysts.展开更多
文摘The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS QDs and hollow nanotube In_(2)O_(3)is successfully achieved using an electrostatic self-assembly method.Under visible light irradiation,all CdS-In_(2)O_(3)composites exhibit higher hydrogen evolution efficiency compared to pure CdS QDs.Notably,the photocatalytic H_(2)evolution rate of the optimal CdS-7%In_(2)O_(3)composite is determined to be 2258.59μmol g^(−1)h^(−1),approximately 12.3 times higher than that of pure CdS.The cyclic test indicates that the CdS-In_(2)O_(3)composite maintains considerable activity even after 5 cycles,indicating its excellent stability.In situ X-ray photoelectron spectroscopy and density functional theory calculations confirm that carrier migration in CdS-In_(2)O_(3)composites adheres to a typical S-scheme heterojunction mechanism.Additionally,a series of characterizations demonstrate that the formation of S-scheme heterojunctions between In_(2)O_(3)and CdS inhibits charge recombination and accelerates the separation and migration of photogenerated carriers in the CdS QDs,thus achieving enhanced photocatalytic performance.This work elucidates the pivotal role of S-scheme heterojunctions in photocatalytic H_(2)production and offers novel insights into the construction of effective composite photocatalysts.
基金supported by National Natural Science Foundation of China (No. 40743020 No. 40973078)Tianjin Natural Science Foundation (No. 08JCYBJC10400 and No. 06YFSZSF05100)
文摘This study describes the adsorption features of cadmium on Fe2O3 and MnO2 in alkaline saline conditions. The adsorption reached equilibrium in 6 hours under alkaline conditions. The absorption of cadmium on Fe2O3 and MnO2 was consistent with Freundlich absorption isotherms, and the corresponding adsorption capacities were 16.3 and 16.7 mg·g-1, respectively. Moreover, the adsorption quantity of cadmium on Fe2O3 and MnO2 rose with increas-ing pH from acidic to neutral, and reached the maximum at pH= 9. The coexisting chlorides reduced the adsorption capacity of Fe2O3 and MnO2. The influence intensities of different cations follow the order of CaCl2>>KCl>NaCl. However, the influence of sodium salts on the capacities of Fe2O3 and MnO2 to adsorb cadmium appeared more complicated: the relatively low concentrations of sodium salts could reduce the adsorption capacity; with increasing concentrations of sodium salts, e.g. NaCl and NaNO3. the adsorption capacity decreased continually. Moreover, due to the competition adsorption and precipitation effects, the adsorption capabilities of Na2CO3, NaH2PO4 and Na2HSO4 could also be reduced and cadmium concentrations in the solution were reduced as well.
基金supported by the Natural Science Foundation of Henan(242300421230)the Young Teacher Fundamental Research Cultivation Program of Zhengzhou University(JC23557030)the National Natural Science Foundation of China(U21A20281 and 22208322)。
文摘Noble metal-loaded layered hydroxides exhibit high efficiency in electrocatalyzing water splitting.However,their widespread use as bifunctional electrocatalysts is hindered by low metal loading,inefficient yield,and complex synthesis processes.In this work,platinum atoms were anchored onto nickel-iron layered double hydroxide/carbon nanotube(LDH/CNT)hybrid electrocatalysts by using a straightforward milling technique with K_(2)Pt Cl_(6)·6H_(2)O as the Pt source.By adjusting the Pt-to-Fe ratio to 1/2 and 1/10,excellent electrocatalysts—Pt_(1/6)-Ni_(2/3)Fe_(1/3)-LDH/CNT and Pt_(1/30)-Ni_(2/3)Fe_(1/3)-LDH/CNT—were achieved with superior performance in hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),outperforming the corresponding commercial Pt/C(20 wt%)and Ru O_(2)electrocatalysts.The enhanced electrochemical performance is attributed to the modification of Pt's electronic structure,which exhibits electron-rich states for HER and electrondeficient states for OER,significantly boosting Pt's electrochemical activity.Furthermore,the simple milling technology for controlling Pt loading offers a promising approach for scaling up the production of electrocatalysts.
