Zn-vacancy mediated electron-hole separation in ZnS/g-C3N4 heterojunction for efficient visible-light photocatalytic hydrogen production

Defect‐Type‐Dependent Near‐Infrared‐Driven Photocatalytic Bacterial Inactivation by Defective Bi2S3 nanorods

“…The highest photocurrent of BS-3 suggests the most efficient chargephotogeneration and the greatest possibilityo fg ood catalytic activity. [1] Compared with BS-5, the photocurrent of BS-3 is significantly increased, whereas that of BS-1 is dramatically decreased, even thoughB S-1 has higher light absorption ability than BS-5.…”

“…By comparison of the XRD patterns and SEM images of BS-1, BS-3, and BS-5, it can be discerned that the different durations of solvothermal treatment did not change the morphology or the crystal phase of Bi 2 S 3 .H owever,f rom the obtainedE SR spectra (Figure 2), BS-1, BS-3, and BS-5 samples show different intensities of ESR signals (g % 1.994) regardless of the absence or presenceo fN IR irradiation. [1,4,20,21] Based on this, it would be suitable to explore Bi/S ratios obtainedf rom XPS to evaluate the effects of surface defects. As ESR tests can only prove the presence of defects caused by unpaired electrons, it cannotd etermine the type of vacancy.T hus, X-ray photoelectron spectroscopy (XPS) was appliedt oi nvestigate the atomic ratios of these three samples to find out their vacancy type.…”

“…[3] XPS can be employed as ac haracterization technique to investigate the surface( up to ad epth of 3nm) chemical components and states of the materials. [1,4,20,21] Based on this, it would be suitable to explore Bi/S ratios obtainedf rom XPS to evaluate the effects of surface defects. TheB i/S atomic ratios of the three samples differed greatly based on the XPS analysis (Table 1), suggesting BS-1 is sulfur-deficient Bi 2 S 3 and BS-3 is bismuth-deficient Bi 2 S 3 ,w hereas the Bi/S atomicr atio of BS-5 is close to the theoretical value (i.e.,B i 2 S 3 ), suggesting no or relatively little element vacancy.M oreover,t he surface valence states of both bismuth and sulfur showeds hifts in the binding energies (see the Supporting Information, Figure S2), which could be attributed to variations in the chemical environmentc aused by sulfur or bismuth vacancies.…”

“…[1][2][3][4][5][6] It has been widely accepted that the introduction of vacancies induces the formation of new energy levels,w hich can narrowt he band gap of the catalysts and thus enhance their light-harvesting ability.F or example, the introduction of oxygen vacanciess ignificantly improves the visible-light response in TiO 2 , [7,8] BiPO 4 , [9] Bi 5 O 7 Br, [10] BiOBr, [11] BiOCl, [12] BiO 2Àx , [13] and ZnO photocatalysts. [1][2][3][4][5][6] It has been widely accepted that the introduction of vacancies induces the formation of new energy levels,w hich can narrowt he band gap of the catalysts and thus enhance their light-harvesting ability.F or example, the introduction of oxygen vacanciess ignificantly improves the visible-light response in TiO 2 , [7,8] BiPO 4 , [9] Bi 5 O 7 Br, [10] BiOBr, [11] BiOCl, [12] BiO 2Àx , [13] and ZnO photocatalysts.…”

“…In studies of photo-and electrocatalysis during the last few decades, vacancy engineering has been aq uite powerful strategy to tailor the photo-or electrocatalytic efficiency. [1][2][3][4][5][6] It has been widely accepted that the introduction of vacancies induces the formation of new energy levels,w hich can narrowt he band gap of the catalysts and thus enhance their light-harvesting ability.F or example, the introduction of oxygen vacanciess ignificantly improves the visible-light response in TiO 2 , [7,8] BiPO 4 , [9] Bi 5 O 7 Br, [10] BiOBr, [11] BiOCl, [12] BiO 2Àx , [13] and ZnO photocatalysts. [14] In addition, the introduced vacancies can modify the charge-transfer kinetics for efficient charges eparation.…”