Enhanced Visible-Light Photocatalytic Activity of BiOI/BiOCl Heterojunctions: Key Role of Crystal Facet Combination

Abstract

Two comparable models of BiOI/BiOCl heterojuctions with different interface structures (crystal surface orientation and crystal surface combination), denoted as BiOI(001)/BiOCl(001) and BiOI(001)/BiOCl(010), have been prepared via integrating heterojuncton nanostructure construction with crystal facet engineering. BiOI(001)/BiOCl(010) had a greater degree of lattice mismatch and displayed higher visible-light photocatalytic activity than BiOI(001)/BiOCl(001). In general, the activity of a photocatalyst (ηPC) has a positive correlation with light harvesting (ηLH), charge separation (ηCS), and charge injection (ηCI). On the basis of the experimental results, we considered that the higher ηCI value of BiOI(001)/BiOCl(010) was the main reason for its better visible-light photocatalytic performance. In combination with theoretical calculations, we found that the higher ηCI value of BiOI(001)/BiOCl(010) was the result of a shorter photogenerated electron diffusion distance, assisted by the self-induced internal electric fields of the BiOCl slabs. This indicated that the crystal facet combination is the key to enhancing the photocatalytic activity of BiOI/BiOCl. Our work offers an archetype for the further design of heterojunction photocatalysts with a fine tuning of the interface structures in order to reach optimized charge injection and enhanced photocatalytic activity.

In situ assembly of BiOI@Bi 12 O 17 Cl 2 p - n junction: charge induced unique front-lateral surfaces coupling heterostructure with high exposure of BiOI {001} active facets for robust and nonselective photocatalysis

“…5c . It is worthy to note that this front-lateral surfaces coupling is obviously different from the most reported layered bismuth-based composites in which the nanosheets/plates are combined in a 2D-2D way [36,37].…”

“…2dshows the Cl 2p peak of Bi12O17Cl2. It can be deconvoluted into two peaks at 200.2 eV and 198.4 eV, which are attributed to the Cl 2p1/2 and Cl 2p3/2, respectively[36]. As shown inFig.…”

“…On the other hand, the controlled synthesis of BiOI with exposed {001} active facets enables it much improved photocatalytic activity [36,37]. Nevertheless, developing absorbing BiOI heterostructure with exposed active facets has not been achieved.…”

Highly efficient and visible light driven Ni0.5Zn0.5Fe2O4@PANI modified BiOCl heterocomposite catalyst for water remediation

“…Simultaneously, photogenerated holes in the VB of BiOCl transfer into the HOMO of PANI and further transfer to the VB of NZF. As a result, a rapid charge separation and slow charge recombination occur and any transferred charge carriers may participate in the subsequent redox reactions with either the oxidants or the reductants in the solution, thereby resulting in higher photocatalytic activity [73]. A possible reaction path for redox reaction is as follows:…”

Three-Dimensional Bi $$_{5}$$ 5 O $$_{7}$$ 7 I Photocatalysts for Efficient Removal of NO in Air Under Visible Light

“…Besides, Bi 6s and O 2p orbitals can form a new valence band in a row above the original position through orbital hybridization, thereby effectively reducing the band gap and producing visible light absorption (Martinez Suarez et al 2015). Especially, bismuth oxyhalides, as a typical layerstructured photocatalytic materials, have been successfully prepared and applied in the water purification of organic pollutants (Ahern et al 2015;Henle et al 2007;Sun et al 2015;Wang et al 2011). At the same time, its application in the field of air pollution control is quite rare (Ai et al 2009;Zhang et al 2013;Zhang et al 2016).…”