The development of sustainable heterogeneous catalysts is essential for advancing green chemistry. Herein, we report the fabrication of 3D‐printed geopolymer‐based catalysts (GeoPol) derived from natural kaolin and their evaluation in the Knoevenagel condensation, a benchmark carbon–carbon bond‐forming reaction. The catalysts were obtained by alkali activation of metakaolin, optimized with polyethylene glycol to enable additive manufacturing, and printed into architectures designed to enhance mass transfer. Structural analyses (X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and Brunauer–Emmett‐Teller surface area measurements) confirmed the formation of amorphous sodium aluminosilicate hydrate gels with stable microstructures and accessible surface tarea. Under optimized conditions (100 mg catalyst/mmol substrate, ethanol, room temperature), GeoPol promoted Knoevenagel condensations between ethyl cyanoacetate and carbonyl compounds with yields up to 98% and broad substrate tolerance, including electron‐rich, electron‐deficient, and heteroaromatic aldehydes. The system was further validated in one‐pot and microwave‐assisted synthesis, achieving high efficiency under intensified conditions. A gram‐scale reaction confirmed scalability with 97% isolated yield. Reusability studies demonstrated ≥82% activity retention after five cycles, with carbonaceous deposits identified as the main cause of deactivation, while mass recovery remained above 95%. The method was extended to Meldrum's acid, being applied to synthesize an important intermediate for active pharmaceutical ingredients. These findings highlight 3D‐printed geopolymers as robust, low‐cost, and recyclable catalysts that align with the principles of green chemistry, offering a practical platform for sustainable organic synthesis.
Albino et al. (Sun,) studied this question.