Facet effect of metal-organic frameworks on supporting co-catalysts for photocatalytic hydrogen peroxide production

• Published in: Chinese chemical letters 2024-09, p.110472, Article 110472
• Main Authors: Du, Peiyang, Yuan, Ling, Bao, Tong, Xi, Yamin, Li, Jiaxin, Bi, Yin, Yin, Luli, Wang, Jing, Liu, Chao
• Format: Article
• Language: English
• Subjects: Co-catalyst; Facet effect; H2O2 production; MOF; Photocatalyst
• ISSN: 1001-8417
• DOI: 10.1016/j.cclet.2024.110472

The facet effect of metal-organic frameworks (MOF) on regulating the property of loaded co-catalysts is an important but unexplored issue in the field of photocatalysis. In this work, a series of MIL-125-NH2 polyhedrons (MIL = Materials Institute Lavoisier) with facet exposure of {001}, {001}/{111} and {111} are synthesized and used to load Pd-based co-catalysts for photocatalytic oxygen reduction reaction (ORR) toward H2O2 production. The different facets with distinct chemical environments (Ti-O clusters on {111} facets and carboxyl ligands on {001} facets) result in the selective loading of Pd0 and PdO dominated cocatalysts on {001} and {111} facets, respectively. The {001}/{111} co-exposed MIL-125-NH2 thus enables the spatially separated loading of Pd0 and PdO dual cocatalysts respectively. Pd0 efficiently traps the photoexcited electrons and PdO trends to capture the holes, collaboratively promoting the directional separation of photogenerated electron-hole pairs. As a result, the photocatalytic ORR activity is significantly enhanced with a H2O2 production rate of 128.6 mmol L-1 g-1 h-1, superior than pristine and single cocatalyst modified MIL-125-NH2 samples. Our findings provide new insight into the design of high-performance photocatalysts. A MOF-based photocatalyst with facet-dependent spatial separation of dual cocatalysts is constructed for photocatalytic 2e-ORR to H2O2 with superior performance. [Display omitted]