A Cu-incorporated NASICON catalyst executing one-step conversion of methanol and acetic acid to acrylic acid and its esters

Direct synthesis of acrylic acid (AA) from methanol and acetic acid is promising for the high-value utilization of coal-based chemicals. However, this direct synthesis faces challenges due to limited catalyst functionality or insufficient synergistic effects among multiple active sites. Herein, we constructed a series of bifunctional catalysts (CuO-NSCs) by incorporating Cu into NASICON material for direct synthesis of AA. A total selectivity of 96.0% to AA, methyl acrylate (MA), and methyl acetate was achieved over a 2.5 wt% CuO-NSC catalyst, with the 56.3% selectivity of AA+MA, approximately 23% higher than the one ever reported (33%). Our research revealed that NASICON substrate promoted the formation of more Cu + species, which are crucial redox active sites for methanol dehydrogenation into formaldehyde; furthermore, the appropriate introduction of Cu somewhat regulated surficial acid-base properties, specifically increasing the density of medium-strength acidic and basic sites that are essential for the aldolization of acetic acid and formaldehyde. Apparently, the superior activity of the catalyst was attributed to good synergistic effects between the redox sites and acid-base sites.