Rational Design of Coordination Bond Connected Metal Organic Frameworks/MXene Hybrids for Efficient Solar Water Splitting

• Published in: Advanced functional materials Vol. 32; no. 30
• Main Authors: Shi, Litong, Wu, Chongchong, Wang, Yang, Dou, Yuhai, Yuan, Ding, Li, Hui, Huang, Hongwei, Zhang, Yu, Gates, Ian D., Sun, Xiaodong, Ma, Tianyi
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.07.2022
• Subjects: adsorption energy of water; Carboxyl group; Carrier recombination; Chelation; Chemical bonds; Coordination; coordination bond connected MOFs/MXene; efficient electrons transfer; Heterostructures; Hydrogen evolution; Materials science; Metal-organic frameworks; MXenes; PAW method; Photocatalysis; solar water splitting; Titanium; Water splitting; Zirconium
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202202571

Metal organic frameworks (MOFs) have attracted great interest in photocatalysis, but their activity is hampered by the issue of severe carrier recombination. Here, through a carboxyl group assisted coordination route, MXene decorated with carboxyl groups provides chelation sites enabling coordination with UiO‐66‐NH2(Zr/Ti) (UZT) to fabricate a tightly connected UiO‐66‐NH2(Zr/Ti)/carboxyl‐functionalized MXene (UZT/CFMX) heterostructure. This is the first instance of direct chemical bonding of MOFs‐involved heterostructure via a coordination bond. The critical role of decorated carboxyl groups can be determined so that 1) these can help to establish a strong coordination bond between two materials; 2) act as bridge to promote the electrons transfer from MOFs to MXene, thus relieving carrier recombination, and 3) most interestingly, the carbon atom on the carboxyl group forms a bond with the oxygen from water stimulating the water to dissociate into OH* and H*, thus adding additional reaction pathways for promoting photocatalytic water splitting. Accordingly, the resulting UZT/CFMX shows efficient solar‐driven photocatalytic performance for water splitting. The H2 evolution rate is as high as 2187 µmol g−1 h−1, 20 times higher than that of UZT and 4 times higher than that of UiO‐66‐NH2 (Zr/Ti)/MXene (UZT/MX), also surpassing the majority of reported MOF‐based photocatalysts. Through a unique carboxyl group assisted coordination route, UiO‐66‐NH2(Zr/Ti)/carboxyl‐functionalized MXene (UZT/CFMX) composite with intimate interactions is successfully constructed. Such intimately coupled heterojunctions display high activity for solar‐driven water splitting.