F-Al-OH structural support and Lewis acidic site modulation of aluminium fluoride for durable dehydrofluorination

The dehydrofluorination of 1,1-difluoroethane (R152a) is a Lewis acid–catalyzed reaction in which both catalytic activity and stability are governed by the coordination and acidity of aluminum sites. In this work, a mechanochemical fluorination strategy was developed to construct a partially fluorinated Al-based catalyst with tunable acid properties. By controlling the fluorine-aluminum ratio during ball milling, the in situ formation of AlF 2 (OH) was achieved, serving as a structural stabilizer and electronic modulator. The coexistence of F-Al-O units and unsaturated Al centers provides medium-strength Lewis acid sites, which favor selective C-F bond activation while suppressing side reactions. Comprehensive characterizations (XRD, XPS, 27 Al NMR, and NH 3 -TPD) confirmed that the defect-related F-Al-O structure maintains structural integrity and balanced acidity during reaction. Consequently, the optimized catalyst exhibits excellent activity, selectivity, and long-term stability in R152a dehydrofluorination.