Fig. 1: The synthesis method and structural diagrams of HTiNbO5-X membranes.
a The esterification of benzyl alcohol with acetic anhydride catalyzed by HTiNbO5-X membranes in CH3CN at 23 °C. b Fabrication of the HTiNbO5-X nanosheets and HTiNbO5-X membrane. c TEM image of HTiNbO5-X nanosheets. d AFM image and corresponding height profile of HTiNbO5-X nanosheets. e Pyridine IR spectra and f NH3 TPD profiles of HTiNbO5-X nanosheets and KTiNbO5. g Cross-sectional SEM image of HTiNbO5-X membrane (Inset show the photograph of the as-prepared HTiNbO5-X membrane). h XRD patterns measured for the reaction-state of HTiNbO5-X membranes obtained by different annealing temperatures. i Scheme of the HTiNbO5-X membrane reactor showing the esterification of benzyl alcohol with acetic anhydride. Driven by the pressure difference, the alcohol and anhydride molecules react efficiently within 2D nanochannels. j Symmetry matching between the HOMO of the benzyl alcohol and the LUMO of protonated acetic anhydride in the nanochannels with different interlayer spacing. k Comparison of the conversion and reaction time for bulk and confined reactions. Confined reaction condition: HTiNbO5-X membrane, benzyl alcohol (0.2 M) and acetic anhydride (0.3 M) in CH3CN (10 mL) at 23 °C. Bulk reaction condition: HTiNbO5-X nanosheets (10 mg), benzyl alcohol (0.2 M) and acetic anhydride (0.3 M) in CH3CN (10 mL) at 23 °C for 24 h. Error bars represent standard deviation of three measurements.
