Importantly, the local structure of aDUT-67 differs from both the pristine MOF and the ZrO 2 formed after 6 hours of RHT. In the first shell, Zr-O bonds shorten from 2.2 Å in the pristine MOF to 2.15 Å in aDUT-67, suggesting reduced Zr valency and the presence of Zr cus sites.