Facile Realization of Boosted Near‐Infrared‐Visible Light Driven Photocatalytic Activities of BiOF Nanoparticles through Simultaneously Exploiting Doping and Upconversion Strategy

Abstract

In spite of this, one of the unavoidable issues of photocatalysis is how to take advantage of solar energy efficiently. As we know, the sunlight can be roughly divided into three parts, that is, ultraviolet, visible and near-infrared (NIR) light, in which they take around 5%, 45%, and 50% energy of the sunlight, respectively. [6,7] To date, these widely used photocatalysts, such as ZnO, WO 3 , and TiO 2 , suffer from narrow absorption edge, where the energy originating from visible and NIR light is wasted, resulting in dissatisfied photocatalytic properties. [8][9][10] In order to tackle this shortage, researchers tried to find out other semiconductors and some nano-sized compounds, such as CaAl 5 Fe 7 O 19 , ZnS-CdS, and SiO 2 -TiO 2 , which were promising candidates for photocatalytic and antibacterial applications, were proposed. [11][12][13][14] Thereby, searching for novel semiconductors is a facile and efficient route to develop highly efficient photocatalytic materials.Over the last decades, considerable attention has been attracted in bismuth containing semiconductors since they exhibit promising applications in photocatalysis owing to their superiorities including high stability, suitable energy band gap (i.e., E g ), and nontoxicity. [15,16] Shi et al. reported that the Bi 5 OI 7 and BiO 5 I 2 semiconductors with admirable photocatalytic activities can utilize both ultraviolet and visible lights. [17] As a member of bismuth containing semiconductors, the investigation on the photocatalytic properties of BiOX (X = F, Cl, Br, and I), which displays unique matlockite structure with [XBiOOBiX] layers, has been intensively performed. [18,19] Particularly, with the help of weak nonbonding van der Waals interaction along the c-axis, [Bi 2 O 2 ] 2+ slabs with positive valence are interleaved by means of two halide ions, leading to the production of internal electric field along the caxis. [18] Note that, the occurrence of the internal electric field enables the separation of electron-hole pairs more efficiently which gives rise to admirable photocatalytic behaviors of BiOX. At present, it has been revealed that the BiOX compounds can capture both ultraviolet and visible lights to photodegrade pollutants (i.e., RhB, methyl orange). [20,21] Nevertheless, these currently developed BiOX photocatalysts still own some deficiencies, such as the harvest of NIR light is insufficient and A facile strategy is put forward to improve the photocatalytic activity of BiOF nanoparticles by simultaneously exploiting doping and upconversion engineering. The Er 3+ /Yb 3+ -codoped BiOF nanoparticles are synthesized via using high-temperature solid-state reaction route. Through employing firstprinciples density functional theory, one knows that the electronic structure of BiOF host is greatly impacted by Er 3+ and Yb 3+ ions doping. Excited by 980 nm, bright upconversion emissions are seen in prepared compounds and their maximum intensities are obtained when x = 0.04. Furthermore, the photocatalytic capacity of the designed n...

Visible–near-Infrared Light-Driven Photocatalytic Characteristics of Er3+/Yb3+-Codoped BiOBr Upconverting Microparticles for Tetracycline Degradation

“…37 Aside from this broad absorption band, other narrow bands located at around 490 ( 4 I 15/2 → 4 F 7/2 ), 522 ( 4 I 15/2 → 2 H 11/2 ), and 656 ( 4 I 15/2 → 4 F 9/2 ) nm originating from Er 3+ are also observed. 9,38 From previous literature, 39,40 it is clear that the E g of a semiconductor can be roughly determined from its UV−vis absorption spectrum by means of the expression of αhv = A(hv − E g ) n (where α, A, and hv are associated with the absorption coefficient, constant, and phonon energy, respectively, and the n value is related to the type of semiconductor). Since the studied samples all belong to indirect semiconductors, the n value is 2.…”

“…3−5 Unfortunately, these above semiconductors suffer from relatively large band gaps (i.e., E g > 3 eV), which should be excited by ultraviolet (UV) light during the photodegradation process. 6,7 However, the UV light only occupies approximately 5% of the energy of sunlight, 8,9 implying that most of the energy is wasted with a low efficiency. Thereby, it is very urgent to develop novel photocatalysts that are able to utilize solar energy efficiently, especially for visible as well as near-infrared (NIR) lights.…”

“…Although the UV−visible light-driven photodegradation is realized in BiOX compounds, 17−19 they are still hardly excited by NIR light, which occupies around 50% of the energy of sunlight. 8,9 Hence, it is necessary to improve the light harvesting ability of BiOX compounds. Nowadays, many strategies, including constructing a heterojunction structure, doping, and creating defects or oxygen vacancies, have been proposed to modify the light harvesting capacity.…”

Improve the Photocatalytic Hydrogen Production Using ZnS@ZnO Twin‐Junction Structure with Isoelectronic Traps

“…In photocatalysis, the catalyst also plays an important role. The commonly used catalysts include oxides, [12] sulfides, [13,14] nitrides, [15,16] and selenide. [17] Thereinto, the energy bandgap (E g ) of oxides is wider so that the oxidation/reduction ability is better, [13] and ZnO has been widely used because of its strong redox ability, non-toxic stability, low price, good crystallization, and easy preparation.…”

Utilizing Upconversion Emission to Improve the Photocatalytic Performance of the BiOI Microplate: A Bifunctional Platform for Pollutant Degradation and Hydrogen Production

“…For the sake of solving these problems, photocatalytic semiconductor compounds have attracted widespread attention because they have admirable characteristics of environmental remediation ( e.g ., water purification and pollution degradation), renewable energy production ( e.g ., water splitting for H 2 production), and so forth. , At present, some semiconductor-mediated photocatalysts, such as TiO 2 , ZnO, and SnO 2 , are commercially available. − However, it is a pity that they cannot harvest the sunlight efficiently because their photocatalytic activities are only able to be realized upon ultraviolet (UV) light irradiation. As is known, the UV light only occupies around 5% of the energy of sunlight, whereas other parts, such as visible (∼45%) and near-infrared (NIR, ∼50%) light, take the domination. , Obviously, the weak light-harvesting ability is a main factor in impacting the photocatalytic properties of photocatalysts. Thus, searching for new photocatalytic semiconductors, which can simultaneously harvest visible and NIR light, is a promising route to improve the photocatalytic activity.…”