Defect-engineered Cr-UiO-66 catalysts for enhanced hydroxyacetone production from 1,2-propanediol via promoted H2O2 activation

A series of Cr-UiO-66 catalysts with ligand-vacancy defects was prepared for the oxidative dehydrogenation of biomass-derived 1,2-propanediol to hydroxyacetone. • A volcano-shaped trend between defect level and hydroxyacetone yield was established. • Moderate ligand vacancies balance H 2 O 2 conversion and the selective formation of hydroxyacetone. • •OH radicals were identified as key species for H 2 O 2 -driven ODH of 1,2-propanediol. The oxidative dehydrogenation (ODH) of biomass-derived 1,2-propanediol (1,2-PDO) to the high-value chemical hydroxyacetone (HA) is a meaningful route for upgrading renewable feedstocks into value-added multifunctional chemicals. In this study, Cr-UiO-66 catalysts with tunable content of ligand vacancies were synthesized for the conversion of 1,2-PDO to HA. Notably, a volcano-shaped relationship was observed between defect density and HA yield. The optimized 0.4Cr-UiO-66 catalyst achieved an HA yield approximately 3 times that of pristine UiO-66, reaching 12.9% at 45 °C after 2 h. Moreover, the catalyst sustained its ODH performance over five reaction runs. Regulating the content of ligand vacancies was shown to modulate the acidic properties of Cr-UiO-66 and H 2 O 2 activation to generate •OH radicals. A moderate level of ligand vacancies enabled a balance between H 2 O 2 activation and selective HA formation, resulting in improved performance. This study highlights ligand-vacancy engineering as an effective strategy for regulating H 2 O 2 activation over UiO-66-based catalysts. It provides meaningful insights for tailoring structural defects in UiO-66 for the ODH valorization of biomass derivatives. Download: Download high-res image (159KB) Download: Download full-size image