<p>Biomass-based aerogel materials are attracting considerable attention in the catalytic industry because of their properties of high porosity, Light weight, and large surface area formed by the interconnected 3D networks. However, the functionalities of most aerogel catalysts are unsatisfactory because of their complicated fabrication process, low catalytic activities, especially low selectivity. Herein, the functionalized alginate-based aerogels were prepared by introducing tetrasodium iminodisuccinate on sodium alginate to increase the number of carboxyl groups on polymer mainchains, aiming to provide more positions for crosslinking Cu²⁺. Furthermore, MOF-5 grew <i>in situ</i> at the Cu-crosslinked positions to synthesize SI-MOF aerogels. Compared with the Cu-SA aerogel, the crosslinking amount of Cu²⁺ in SI-MOF was increased by 8.21% and the compressive strength was improved by 233%. In the phenol hydroxylation catalyzed by SI-MOF, the conversion of phenol reached 70.29% and the selectivity of catechol was notably improved by 91.77% with a ratio of catechol to hydroquinone being 11:1. The fabricated aerogel catalyst provides a new strategy for the catalytic industry.</p> Graphical abstract <p></p>