Selective Exposure of BiOI Oxygen-Rich {110} Facet Induced by BN Nanosheets for Enhanced Photocatalytic Oxidation Performance

Abstract

Photocatalytic oxidation is a promising technology for governing emission of environmental pollutants and managing energy crisis. Typically, the photocatalytic performance of photocatalysts is highly dependent on the type of exposed crystal surfaces. As a semiconductor oxide photocatalyst, the different exposed crystal surfaces of bismuth oxyiodide (BiOI) exhibit different photocatalytic oxidation performances. In this study, we chose BiOI as the model material and provided a novel method to improve the photocatalytic oxidation performance by regulating the main exposed crystal facets. Using boron nitride (BN) nanosheets as the templates, two-dimensional/two-dimensional (2D/2D) BiOI/BN nanocompounds were fabricated via an in situ growth method. Owing to the electrostatic interaction, the positively charged BiOI {001} facets prefer to contact the negatively charged BN {001} facet, thus inducing the exposure of BiOI {110} facets. This was identified via X-ray diffraction and transmission electron microscopy analyses. Compared with BiOI {001} facets, there were more lattice oxygen atoms in the BiOI {110} facets. Thus, the exposure of BiOI {110} facets would promote more surface lattice oxygen atoms exposed on the surface of BiOI, which was confirmed by X-ray photoelectron spectroscopy and density functional theory calculations. To evaluate the photocatalytic oxidation performance of BiOI/BN, the photocatalytic NO oxidation reaction was tested under visible light irradiation (λ > 420 nm). Among all the nanocompounds, the BiOI/BN-1.0:1.4 nanocompound exhibited the best NO oxidation ratio of 44.2%, which was almost 30 times higher than that of pristine BiOI (1.4%). The enhanced photocatalytic activity could be attributed to the following two aspects. One, the successful combination of BN effectively promoted the separation of photogenerated carriers, which was identified by steady-state and time-resolved fluorescence spectra, transient photocurrent responses, and electrochemical impedance spectra. Two, benefiting from the introduction of BN nanosheets, BiOI tends to mainly expose the oxygen-rich {110} facets. As a result, the content of O on the BiOI surface increased from 38.3% to 46.6%. Thus, NO preferred to adsorb on the {110} facets of BiOI nanosheets, which was confirmed by theoretical and experimental results. More importantly, the adsorbed NO spontaneously combined with the lattice oxygen atom of the BiOI (110) surface to form nitrogen dioxide (NO2). These findings can provide a novel strategy to tune exposed oxygen-rich facets by constructing 2D/2D photocatalysts for ensuring efficient photocatalytic oxidation performance.

A Simple Grinding Method for Preparing Ultra-Thin Boron Nanosheets

“…These two low binding energy peaks (189.1 eV and 187.6 eV) are the red-shifted relative to the location of the block boron, which is most likely the existence of two different B-B bonds in the block boron. The peak observed at 191.4 eV is attributed to the complete oxidation state of boron in B 2 O 3 , and the binding energy value is consistent with previous reports [ 16 ]. At the same time, it is observed that the proportion of boron oxide peak is very small, and mainly B-B peak with the binding energy of 187.6 eV related to B-B bonding is the most dominant.…”

Self‐Supported Pd Nanorod Arrays for High‐Efficient Nitrate Electroreduction to Ammonia

“…[47,48] In addition, the peak in O 1s spectra in Figure S3c (Supporting Information) can be divided into two peaks that belong to hydroxyl species (O1, 531.5 eV) and chemisorbed water (O2, 532.6 eV). [49][50][51] It is obvious that the hydroxyl species are the most prevalent kind of oxygen, which supports the in situ introduction of Ni element even more. [52,53] These results confirm that a loading amount of active elements is present in Pd/NF.…”

Dual-Function Reaction Center for Simultaneous Activation of CH4 and O2 via Oxygen Vacancies during Direct Selective Oxidation of CH4 into CH3OH

“…First, the photocatalytic activities of BiOCl nanosheets exposed with the (010) and (001) facets were tested to screen a superior surface for the introduction of oxygen vacancies to investigate the surface adsorption and reaction behaviors, and BiOCl (010) was selected due to the higher production yield of CH 3 OH compared to the BiOCl (001) sample (Figure S2). Thus, the following surface adsorption behaviors for both CH 4 and O 2 were studied on the oxygen vacancy-modified BiOCl (010) surface. Interestingly, the optimal adsorption site of CH 4 was determined to be the Bi metal site instead of the oxygen vacancy on BiOCl (010) with or without the oxygen vacancy (Figure ), considering the adsorption energies on different adsorption sites (Figure S2).…”