The selectivity of gas sensing materials is increasingly important for their applications. The oxygenregulated SnO2 films with(110) and(101) preferred orientation were obtained through magnetron sputtering, followed b...The selectivity of gas sensing materials is increasingly important for their applications. The oxygenregulated SnO2 films with(110) and(101) preferred orientation were obtained through magnetron sputtering, followed by annealing treatment. Their micro-structure, surface morphology and gas response were investigated by advanced structural characterization and property measurement. The results showed that the as-prepared(110)-oriented SnO2 film was oxygen-rich and had more adsorption sites while the as-prepared(101)-oriented SnO2 film was oxygen-poor and more sensitive to de-oxidation.H2 gas sensitivity, response speed, selectivity between H2 and CO of the(110)-orientated SnO2 film was superior to that of the(101)-orientated SnO2 film. After treated at high temperature and high vacuum,the reduction of gas-sensing properties of the annealed(110) SnO2 film was much more than that of the annealed(101) SnO2 film. The lattice oxygen was responsible for the difference in gas-sensing response between(110) and(101)-oriented SnO2 films under oxygen regulation. This work indicated the gassensing selectivity of the different crystal planes in SnO2 film, providing a significant reference for design and extension of the related materials.展开更多
Constructing heterostructures with narrow-band-gap semiconductors is a promising strategy to extend light absorption range of graphitic carbon nitride(g-C_(3)N_(4))and simultaneously promote charge separation for its ...Constructing heterostructures with narrow-band-gap semiconductors is a promising strategy to extend light absorption range of graphitic carbon nitride(g-C_(3)N_(4))and simultaneously promote charge separation for its photocatalytic activity improvement.However,its highly localized electronic states of g-C_(3)N_(4)hinder photo-carrier migration through bulk towards heterostructure interfaces,resulting in low charge carrier separation efficiency of solid bulk g-C_(3)N_(4)-based heterostructures.Herein,porous g-C_(3)N_(4)(PCN)material with greatly shortened migration distance of photo-carriers from bulk to surface was used as an effective substrate to host Cd Se quantum dots to construct type II heterostructure of Cd Se/PCN for photocatalytic hydrogen production.The homogeneous modification of the Cd Se quantum dots throughout the whole bulk of PCN together with proper band alignments between Cd Se and PCN enables the effective separation of photo-generated charge carriers in the heterostructure.Consequently,the Cd Se/PCN heterostructure photocatalyst gives the greatly enhanced photocatalytic hydrogen production activity of192.3μmol h^(-1),which is 4.4 and 8.1 times that of Cd Se and PCN,respectively.This work provides a feasible strategy to construct carbon nitride-based heterostructure photocatalysts for boosting visible light driven water splitting performance.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51502126 and 51874169)the Natural Science Foundation of Liaoning Province (No. 20180550802)
文摘The selectivity of gas sensing materials is increasingly important for their applications. The oxygenregulated SnO2 films with(110) and(101) preferred orientation were obtained through magnetron sputtering, followed by annealing treatment. Their micro-structure, surface morphology and gas response were investigated by advanced structural characterization and property measurement. The results showed that the as-prepared(110)-oriented SnO2 film was oxygen-rich and had more adsorption sites while the as-prepared(101)-oriented SnO2 film was oxygen-poor and more sensitive to de-oxidation.H2 gas sensitivity, response speed, selectivity between H2 and CO of the(110)-orientated SnO2 film was superior to that of the(101)-orientated SnO2 film. After treated at high temperature and high vacuum,the reduction of gas-sensing properties of the annealed(110) SnO2 film was much more than that of the annealed(101) SnO2 film. The lattice oxygen was responsible for the difference in gas-sensing response between(110) and(101)-oriented SnO2 films under oxygen regulation. This work indicated the gassensing selectivity of the different crystal planes in SnO2 film, providing a significant reference for design and extension of the related materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52002377,51825204 and 21633009)the China Postdoctoral Science Foundation(Nos.2020M681003 and 2020TQ0327)the Natural Science Foundation of Liaoning Province(No.2020BS009)。
文摘Constructing heterostructures with narrow-band-gap semiconductors is a promising strategy to extend light absorption range of graphitic carbon nitride(g-C_(3)N_(4))and simultaneously promote charge separation for its photocatalytic activity improvement.However,its highly localized electronic states of g-C_(3)N_(4)hinder photo-carrier migration through bulk towards heterostructure interfaces,resulting in low charge carrier separation efficiency of solid bulk g-C_(3)N_(4)-based heterostructures.Herein,porous g-C_(3)N_(4)(PCN)material with greatly shortened migration distance of photo-carriers from bulk to surface was used as an effective substrate to host Cd Se quantum dots to construct type II heterostructure of Cd Se/PCN for photocatalytic hydrogen production.The homogeneous modification of the Cd Se quantum dots throughout the whole bulk of PCN together with proper band alignments between Cd Se and PCN enables the effective separation of photo-generated charge carriers in the heterostructure.Consequently,the Cd Se/PCN heterostructure photocatalyst gives the greatly enhanced photocatalytic hydrogen production activity of192.3μmol h^(-1),which is 4.4 and 8.1 times that of Cd Se and PCN,respectively.This work provides a feasible strategy to construct carbon nitride-based heterostructure photocatalysts for boosting visible light driven water splitting performance.
