Constructing the Pd/PdO/β‐Bi₂O₃ microspheres with enhanced photocatalytic activity for Bisphenol A degradation and NO removal

Abstract

BACKGROUND: Photocatalysis is one of the effective ways to solve the problem of water and gas pollution. An excellent photocatalyst should have the following advantages: efficient photocatalytic activity for gas and water pollutants, recyclable and stable characteristics, non-toxic and low-cost. Constructing heterojunctions and introducing oxygen vacancies (OVs) are two effective measures to achieve these targets. RESULTS: It is found that the 1.0% Pd/PdO/ -Bi 2 O 3 exhibits the best photocatalytic activity with an efficiency of 97.4% for Bisphenol A (BPA) degradation and 47.6% for nitric oxide (NO) removal within 30 min. The 1.0% Pd/PdO/ -Bi 2 O 3 composite shows 23.3% efficiency in the photodegradation of BPA under 595 nm monochromatic light irradiation, while -Bi 2 O 3 tends to be invalid. Moreover, the OVs promote the removal of NO without irradiation. CONCLUSION: In this work, a novel ternary Pd/PdO/ -Bi 2 O 3 material as high-performance photocatalyst for the BPA degradation and NO removal was synthesized. The presence of OVs promotes the activation of the oxygen molecule, thereby facilitating the photocatalytic process. The p-n junction of PdO/ -Bi 2 O 3 and the Schottky barrier of Pd/ -Bi2 O 3 significantly limit the recombination of photoinduced electron-hole pairs in the composite. Furthermore, an artifact in the electron spin resonance (ESR) spectrum obtained by spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as adducts confirms that both hydroxyl radical (•OH) and superoxide radical (•O 2 − ) species are involved in the photocatalytic process. The present work offers a new perspective for developing the composite photocatalysts with high efficiency through loading of metal nanoparticles and creating an heterojunction.

Photocatalytic degradation of organic dyes: Pd-γ-Al2O3 and PdO-γ-Al2O3 as potential photocatalysts

“…In addition, Pd NPs were fabricated via ultrasonication of Andean blackberry leaf extract and were used for photocatalytic degradation of methylene blue. 23 Rao et al 24 reported enhanced photocatalytic degradation of bisphenol A by Pd/PdO/β-Bi 2 O 3 microspheres and M. A. Khan's research team 25 used guar gum as stabilizer to synthesize Pd NPs and applied the Pd NPs as catalysts for the degradation of azo dyes. However, these methods are complicated and difficult for synthesizing Pd NPs and some require sophisticated equipment.…”

Detoxification of Endocrine Disruptors in Water Using Visible-Light-Active Nanostructures: A Review

“…The creation of O v defects and attachment of noble-metal nanoparticles can relax the above-mentioned problems. A ternary photocatalyst, Pd/PdO/β-Bi 2 O 3 , has been reported for BPA degradation by Zhu et al The microsphere photocatalysts were formed by assembling innumerable nanosheets. The improved light absorption of Pd nanoparticles, enhanced charge-carrier separation between PdO and a β-Bi 2 O 3 heterojunction, and Schottky contact between Pd and β-Bi 2 O 3 synergistically played important roles.…”

Metal Titanate (ATiO3, A: Ni, Co, Mg, Zn) Nanorods for Toluene Photooxidation under LED Illumination

“…Chen et al, synthesized Bi-BiPO 4 nanocomposites through in situ solvothermal reduction for NO removal [52]. Rao et al, constructed Pb/PbO/β-Bi 2 O 3 microspheres for bisphenol A degradation and NO removal [53] and Wang et al, obtained three types of supported Cobalt catalysts (CoO x /SiO 2 , CoO x /Al 2 O 3, CoO x /TiO 2 ) for CO oxidation [54]. There are limited reports for metal titanates in degrading gaseous pollutants.…”