Enhanced photocatalytic performances of n-TiO₂ nanotubes by uniform creation of p–n heterojunctions with p-Bi₂O₃ quantum dots

Abstract

An ultrasonication-assisted successive ionic layer adsorption and reaction (SILAR) strategy was developed for uniform deposition of high density p-type Bi2O3 quantum dots on n-type TiO2 nanotube arrays (Bi2O3@TiO2 NTAs), which were constructed by electrochemical anodization in ethylene glycol containing the electrolyte. Compared with pristine TiO2 NTAs, the Bi2O3 quantum dots sensitized TiO2 NTAs exhibited highly efficient photocatalytic degradation of methyl orange (MO). The kinetic constant of Bi2O3@TiO2 NTAs prepared by an ultrasonication-assisted SILAR process of 4 cycles was 1.95 times higher than that of the pristine TiO2 NTA counterpart. The highly efficient photocatalytic activity is attributed to the synergistic effect between the formation of a uniform p-n heterojunction with high-density for enhancing light absorption and facilitating photogenerated electron-hole separation/transfer. The results suggest that Bi2O3@TiO2 p-n heterojunction nanotube arrays are very promising for enhancing the photocatalytic activity and open up a promising strategy for designing and constructing high efficiency heterogeneous semiconductor photocatalysts.

The highly enhanced visible light photocatalytic degradation of gaseous o -dichlorobenzene through fabricating like-flowers BiPO 4 /BiOBr p-n heterojunction composites

“…Among them, BiOBr microspheres have attracted much attention owing to its large surface area, which can enhance the physical adsorption [29]. On the other hand, p-n heterojunction, which can be as an efficient and promising method for enhancing the photocatalytic activity of BiOBr, can extend the probability of photo-induced electron-hole separation via an additional internal electric field [27,[34][35][36]. Up to now, some p-n heterojunction photocatalysts have been developed, for example BiOBr nanosheets@TiO 2 nanobelts [37], BiOBr/CoFe 2 O 4 [9] and Bi 2 WO 6 /BiOBr [38].…”

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

“…Immobilisation of the TiO 2 film simplifies the separation of the photocatalystp ost-use, and reducest he chance that any nanoscale materials will remain in solution-a health risk which has recently been broughtt oa ttentioni nt he literature. [34][35][36][37] While BiOI SILAR for photovoltaica pplicationsh as been previouslys tudied, [38][39][40] to the BiOI nanoplates were deposited upon af ilm of TiO 2 nanoparticles derived from ac ommercial source using as imple room temperature sequential ionic layer adsorption and reaction (SILAR) method.X -ray diffraction, X-ray photoelectron spectroscopy and electron microscopies have been used to confirm the crystal phase, chemical states of key elements and morphologyofthe BiOI nanoplate-TiO 2 composites. [31][32][33] For the purposes of photocatalysis SILARi sr elatively unexplored and relatively few examples have been reported.…”

Continuous-Flow Photocatalytic Degradation of Organics Using Modified TiO2 Nanocomposites

“…In GO-TNTs and RGO-TNTs, carbon peaks were also observed together with Ti and oxygen peaks as shown in Figure 2b,c, respectively. In the EDX (Figure 2d), the deposit was mostly comprised of bismuth [31,32] EDX spectrum of Bi-TNTs (Figure 2d), the deposit was mostly comprised of bismuth [31,32]. These EDX results correspond to Sections 2.1.4 and 2.1.6.…”

“…This can be confirmed from AES results, which show that RGO, Bi, and GO were effectively composite on the surfaces of anodized TNTs. EDX spectrum of Bi-TNTs (Figure 2d), the deposit was mostly comprised of bismuth [31,32]. These EDX results correspond to Sections 2.1.4 and 2.1.6.…”