Controllable synthesis of Titania‐Supported Bismuth Oxyiodide Heterostructured Nanofibers with Highly Exposed (1 1 0) Bismuth Oxyiodide Facets for Enhanced Photocatalytic Activity

Abstract

Bismuth oxyiodide/titanium dioxide (BiOI/TiO2) heterostructured nanofibers with exposed (1 1 0) BiOI facets were synthesized by electrospinning and hydrothermal methods. The BiOI/TiO2 heterostructures with exposed (1 1 0) BiOI facets exhibited an enhanced photoreactivity, for which the methylene blue and phenol degradation rate is increased by more than two times and the photocurrent density is 12 times as high as that of BiOI with exposed (1 1 0) facets. EPR spectroscopy indicated that the hydroxyl radicals and superoxide radicals could be generated by BiOI/TiO2 heterostructures with exposed (1 1 0) BiOI facets. Based on the experimental results, the enhancement of the photocatalytic activity could be attributed to the strong oxidization by hydroxyl radicals, enlarged band gap, lowered valence band position, and suppressed recombination of photoinduced electron–hole pairs by the manipulation of heterostructures with exposed (1 1 0) BiOI reactive facets.

SILAR BiOI‐Sensitized TiO2 Films for Visible‐Light Photocatalytic Degradation of Rhodamine B and 4‐Chlorophenol

“…As found by the valence band XPS measurements, the BiOI valence band lies 1.7 eV above that of TiO 2 ,a nd hence the conduction band minimum lies at av alue of (1.7 + E g )a bove the TiO 2 valenceb and. [27,48] This heterojunction has recently been shown by scavenginge xperiments carried out by Luo et al [56] to degrade organic speciesv ia the formation of the superoxide and hydroxyl radicals under visiblel ight as shown in Figure7.T he formationo fap-n junction is advantageous in drivingp hotoexcited electrons and holes away from one another at the interface between two materials, improving charge separation and therefore photocatalytic activity.A s such we have established that the energetics of the BiOI-TiO 2 heterojunction allows both the absorption of visible light, and am echanism for chargeseparation across the interface. Therefore, electrons excited by visible light incident upon BiOI have a0 .7 eV driving force to separatef rom their corresponding holes by transport across the TiO 2 -BiOI interface.…”

“…This process, known as self-sensitisation is often overlooked in the literature but can be very significant,i ndeed in our previousw ork we found that it can be the differenceb etween af unctioning and nonfunctioning photocatalyst. We note that our study was performed [52] reverse microemulsion 250 Wh alogen lamp (> 420 nm) methylo range0.8699h À1 (14.5 10 À3 min À1 )L iu et al [53] electrospinning &s olvothermal 500 WX elamp(> 400 nm) methylene blue 0.015min À1 Zhang et al [54] electrospinning &hydrothermal 500 WX elamp(> 420 nm) methylene blue 83 %d egradationi n1 80 mins Luo et al [56] using an immobilised film suitable for practical recycling and used am uch lower-power light source than the other studies. In view of this, the best photocatalyst film (5xBiOI) wass elected from this initial screening for further testing upon the photobleaching of the UV only absorbing organic pollutant 4-chlorophenol( 4-CP) (Figure 9b).…”

“…We note that our study was performed 500 Wh alogen-tungsten lamp( > 420 nm) methylo range 1.3925 h À1 (23.2 10 À3 min À1 )Z hang et al [28] electrospinning &h ydrothermal 500 WX elamp(> 420 nm) rhodamineB 92 %d egradationi n1 35 mins Liaoetal. [52] reverse microemulsion 250 Wh alogen lamp (> 420 nm) methylo range0.8699h À1 (14.5 10 À3 min À1 )L iu et al [53] electrospinning &s olvothermal 500 WX elamp(> 400 nm) methylene blue 0.015min À1 Zhang et al [54] electrospinning &hydrothermal 500 WX elamp(> 420 nm) methylene blue 83 %d egradationi n1 80 mins Luo et al [56] ChemPhysChem 2017, 18,728 -735 www.chemphyschem.org using an immobilised film suitable for practical recycling and used am uch lower-power light source than the other studies. Despite this, 5xBiOI performse ither similarly or better than the previously reported materials in the photocatalytic degradation of dyes.…”

A Mechanism Investigation of how the Alloying Effect Improves the Photocatalytic Nitrate Reduction Activity of Bismuth Oxyhalide Nanosheets

“…[11][12][13] In the past decades, exploring advanced strategies to enhance e-h separation, including morphological manipulation, crystal facets regulation as well as semiconductor recombination etc, are the hotpots of researches for photocatalysis technology. [14][15][16][17][18][19] Recently, designing alloyed semiconductors has become an exciting research area for constructing highly active new photocatalysts due to the unique influence of alloying characteristics on the geometry structure and electronic distribution. [20,21] Bismuth-based ternary oxide photocatalysts, bismuth oxyhalides (BiOXs, X=Cl, Br, I), are the typical visible light photocatalyst and have excellent catalytic activity than other materials.…”

Solvothermal-Assisted Synthesis of Biomass Carbon Quantum Dots/Bismuth Oxyiodide Microflower for Enhanced Photocatalytic Activity

“…Therefore, it is necessary to further improve the photocatalytic activity for practical applications. Up to now, some strategies have been proposed to improve the photocatalytic activity of BiOI, 23,24 such as modi¯ed by noble metals, 25 constructed the heterojunctions, 26,27 crystal-facet control [28][29][30] and sensitizer. 31 Biomass carbon quantum dots (CQDs), as a new carbon nanomaterial, has been widely used as an efcient component in design of photocatalyst owing to its excellent characteristics, such as chemical stability, low toxicity, unique edge e®ects and quantum con¯nement.…”