Development and study of a bifunctional photocatalyst based on SAPO-34 molecular sieve

• Published in: New journal of chemistry Vol. 47; no. 14; pp. 6563 - 6576
• Main Authors: Wang, Run-quan, Chen, Wan-ping, Zhang, Yue-rong, Song, Kai, Tian, Yuan, Li, Jia-xian, Shi, Gao-feng, Wang, Guo-ying
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 03.04.2023
• Subjects: Acids; Aqueous solutions; Bismuth oxides; Crystals; Electrons; Energy levels; Formaldehyde; Isotopes; Mathematical analysis; Molecular orbitals; Molecular sieves; Photocatalysis; Photocatalysts; Photodegradation; Vanadates
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d3nj00087g

A new bifunctional photocatalyst was constructed from a modified SAPO-34 molecular sieve successfully connected with BiVO 4 crystals through O bridges. The new as-fabricated catalyst not only had enriched active sites of B-acid and L-acid on the surface of the molecular sieve but also enriched active sites of L-acid on the surface of the molecular sieve. The electron-transfer ability between the SAPO-34 molecular sieve and BiVO 4 crystals was improved, and the recombination of electrons and holes in BiVO 4 crystals was inhibited. With the synergistic action of the B-acid and L-acid, the molecular zeolite showed very high activity for the photocatalytic degradation of formaldehyde aqueous solution with a photoreaction rate constant of 0.291 min −1 and degradation rate of 84.34%. Compared with the BiVO 4 crystal, the performance improved 10 times. Based on the calculation of the band structure and state density of the BiVO 4 crystal and the HOMO and LUMO energy levels of the SAPO-34 molecular sieve, a mechanism for the photocatalytic degradation of formaldehyde is proposed and the energy levels of the intermediate products were calculated. This study provides a method for the preparation of composite molecular sieve photocatalysts and a new idea for the construction of bifunctional photocatalysts. A new bifunctional photocatalyst was constructed from a modified SAPO-34 molecular sieve successfully connected with BiVO 4 crystals through O bridges.