A Successive Incipient Impregnation Approach for Supporting Prussian Blue Analogues on Porous Carriers for Ammonia Adsorption

This work presents, for the first time, the synthesis of a copper-cobalt-supported Prussian Blue Analogue (PBA) on alumina porous substrates via successive incipient impregnation. This well-established method, commonly used in the preparation of metal-supported catalysts for heterogeneous catalysis, enables cost-effective, large-scale fabrication of PBAs while improving their handling. Two drying protocols, conventional and microwave drying, were investigated to assess their impact on the synthesis efficiency and material properties. Notably, microwave-based drying reduced the total synthesis time to just 5 h, making it ten times faster than the conventional one, while also enhancing crystal dispersion. The latter led to better mass transfer and diffusion during ammonia (NH₃) adsorption, as evidenced by higher kinetic velocity under harsh conditions (6250 ppmv). These findings demonstrate the advantage of combining successive incipient impregnation with microwave drying for the development of tailored porous PBA sorbents.