Constructing 1D/2D BiOI/ZnWO₄p‐n heterojunction photocatalyst with enhanced photocatalytic removal of NO

Abstract

BACKGROUND: Photocatalysis technology based on green renewable solar energy has broad prospects in environmental protection and new energy utilization. The energy of the light can be utilized to convert the pollutants in the environment into non-toxic substances even available products. Due to its low cost and environmental protection, photocatalysis technology has been further developed in the fields of water splitting, sewage treatment and nitrogen oxides (NO x ) removal.RESULTS: In this study, zinc tungstate (ZnWO 4 ) nanorods loaded on bismuth oxyiodide (BiOI) nanosheets with exposed {001} facet forming a 1D/2D BiOI/ZnWO 4 p-n heterojunction photocatalysts were synthesized and their photocatalytic activities for nitric oxide (NO) removal were investigated. The 20% BOI/ZWO composite exhibited the most excellent photocatalytic NO removal performance, which were 32.32% and 48.24% under visible light and simulated sunlight irradiation, respectively. CONCLUSION: A novel 1D/2D BiOI/ZnWO 4 p-n heterojunction was successfully synthesized by a two-step procedure. Compared to the pure ZnWO 4 and BiOI, the 20% BOI/ZWO composite has a significant increase in photocatalytic activity which is attributed to the enhanced visible light absorption and the improved separation of charge carriers. Trapping experiments and electron spin resonance results indicate that the hole (h + ), super oxygen radical (·O 2 − ) and hydroxyl radical (·OH) play minor roles, while the electron (e − ) has a major contribution to the NO removal process. Therefore, the BiOI/ZnWO 4 p-n heterojunction is a promising material for NO removal.

Efficient charge separation of a Z-scheme Bi5O7−δI/CeO2−δ heterojunction with enhanced visible light photocatalytic activity for NO removal

“…45 Finally, some absorption peaks at 1249, 1299, 1339, 1510, 1573, and 1401 cm −1 can be attributed to the oxidation of the adsorbed NO to nitrates, owing to the oxidation of NO to NO 2 − followed by further conversion to NO 3 − . 46,47 After the light excitation, some absorption peaks at 1299, 1510, 1573, and 1741 cm −1 disappeared (Fig. 5b), indicating that the reactants were removed from the photocatalyst surface with time, which is beneficial to the subsequent reaction.…”

Two‐Dimensional Transition Metal Oxides and Chalcogenides for Advanced Photocatalysis: Progress, Challenges, and Opportunities

“…1D/2D: The features of 1D materials include a large aspect ratio, direct charge‐transport pathways, and low reflectance in light scattering and trapping. [ 296 ] In 1D/2D heterostructures, e.g., 1D CdS /2D SnS 2 , [ 297 ] 1D Cd 0.5 Zn 0.5 S/2D Co 0.85 Se NSs, [ 298 ] 1D C/2D MoSe 2 , [ 299 ] 1D Sb 2 S 3 /2D MoS 2 , [ 300 ] 1D WO 2.72 /2D ZnIn 2 S 4 , [ 301 ] 1D BiOI/2D ZnWO 4 , and [ 302 ] 1D BiPO 4 /2D BiOI, [ 303 ] the respective advantages of 1D and 2D materials can be integrated to tackle the drawbacks of a single material. [ 304 ] Wang et al introduced 2D CoS 2 NSs on the surface of 1D CdS to form a Z‐scheme heterostructure ( Figure a).…”

Coral-Shaped TiO2−δ Decorated with Carbon Quantum Dots and Carbon Nanotubes for NO Removal

“…3−5 Photocatalysis is considered to be one of the most economical, environmentally benign, effective, and low-cost processes to remove NO x from the contaminated air. 6 However, a more toxic byproduct, NO 2 , is also generated during the photocatalytic oxidation process of NO x . Therefore, it is necessary to find appropriate photocatalysts for the photooxidative removal of NO x and for the inhibition of NO 2 formation during the photocatalytic process.…”

“…As a typical one-dimensional (1D) carbon material, carbon nanotubes (CNTs) have been widely used in electrochemical biosensing and electrocatalysis because of their unique electron structure of multiple electron orbitals with the hybridization of sp, sp 2 , and sp 3 . 6 CNTs have also been used as cocatalysts for metal oxide semiconductor (MOS) photocatalysts and are considered to be a coadsorbent or support for the adsorption and photocatalytic degradation of organic pollutants because of their excellent electrical conductivity, large electron storage capacity, and tunable surface chemistry. 7 Particularly, the modification of functional groups on the surface of the CNTs can further improve the adsorption capacity of the CNTs for various pollutants.…”

“…The emission of nitrogen oxide (NO x ) has been significantly increased with a rapid industrial development. , NO x has a negative impact on the environment and human health because of its highly toxic nature. Over the past few decades, various physical and chemical methods have been developed to reduce the emission and concentration of NO x in the air. − Photocatalysis is considered to be one of the most economical, environmentally benign, effective, and low-cost processes to remove NO x from the contaminated air . However, a more toxic byproduct, NO 2 , is also generated during the photocatalytic oxidation process of NO x .…”