Molecular additive control of MOF crystallization: effect of phthalocyanine on size and interfacial redox response of ZIF-8

Simple, in situ routes to tune ZIF-8 particle size, interfacial chemistry, and redox functionality—without post-processing—remain limited. In this work, we present a single-step, in situ phthalocyanine (Pc) additive strategy that modulates ZIF-8 crystallization. Without carbonization or extra processing, the approach reduces particle size, adjusts surface/near-surface chemistry, and—when metalated Pc is used—yields a persistent interfacial redox signature. Under identical activation, N₂ sorption retained the microporous ZIF-8 response while developing a hierarchical-like texture consistent with slit-like/interaggregate voids. Detailed surface analysis indicated that Pc was located at or near interfaces with preservation of the sodalite framework. Electrochemical measurements under identical conditions indicated an enhanced interfacial response relative to pristine ZIF-8. Overall, phthalocyanine-guided growth offers a practical, modular handle to tune particle size, interfacial chemistry, and interfacial redox in ZIF-8 using a simple drop-in molecular additive, relevant to adsorption and other transport-limited applications.