Deciphering structural evolution of adsorbed ˙OH species on Zr-oxo nodes of UiO-66 to modulate methane hydroxylation

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 12; no. 6; pp. 3565 - 3574
• Main Authors: Tian, Ling-Chan, Fang, Geqian, Zhou, Yun, Yu, Wenjun, Li, Lin, Hu, Jin-Nian, Wang, Haiyan, Liang, Jin-Xia, Zhu, Chun, Wang, Xiaodong, Lin, Jian
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 06.02.2024
• Subjects: Atomic properties; Catalytic activity; Configurations; Evolution; Hydroxylation; Methane; Nodes; Oxidation; Species; Zirconium
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D3TA05851D

Direct selective oxidation of methane (DSOM) to oxygenates under mild conditions is garnering increasing interest. UiO-66-H MOFs are effective for this reaction, while the active configuration of Zr-oxo nodes with adsorbed ˙OH species need further clarification from the atomic/molecular viewpoint. Here, we detect the evolution of the geometric and electronic structures of adsorbed oxygenic species on Zr-oxo nodes of UiO-66-H via the controlled ˙OH species. DFT calculations reveal a volcano-like curve relationship between the quantity of ˙OH species and the DSOM performance, which is further corroborated by experimental tests. Zr oxo -˙OH is the main active configuration on Zr-oxo nodes of UiO-66-H at low ˙OH concentration, while it evolves to other oxygenic species (˙OOH, O 2 , and H 2 O) due to the self-reaction with the increase of ˙OH concentration, which leads to performance decrease. Furthermore, a critical descriptor of the p-band centers of O atoms in these oxygenic species on the Zr-oxo nodes is established, which can well represent the catalytic activity for the DSOM reaction.