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

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/beta-Bi2O3 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/beta-Bi2O3 composite shows 23.3% efficiency in the photodegradation of BPA under 595 nm monochromatic light irradiation, while beta-Bi2O3 tends to be invalid. Moreover, the OVs promote the removal of NO without irradiation. CONCLUSION In this work, a novel ternary Pd/PdO/beta-Bi2O3 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/beta-Bi2O3 and the Schottky barrier of Pd/beta-Bi2O3 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 (center dot OH) and superoxide radical (center dot 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. (c) 2019 Society of Chemical Industry