Accelerated Crystallization of Zeolites under Ambient Conditions via Microplasma Electrochemistry

Zeolites are typically synthesized with hydrothermal methods at high temperatures with long reaction time, making the process energy-intensive. Here a convenient strategy is introduced for rapid (<60 min) synthesis of high crystallinity NaA zeolites under ambient conditions with microplasma electrochemistry (MIPEC). The resultant NaA zeolites enhance surface area and more structural defects compared to those produced by hydrothermal methods. The electron paramagnetic resonance study demonstrates that the microplasma anode can generate a hundred times more hydroxyl free radicals (·OH) than the microplasma cathode, thereby expediting the zeolite crystallization process. The density function theory calculations also suggest that the abundant ·OH radicals will lower the free energy barrier with the cooperative effect to accelerate the synthesis. The NaA zeolites demonstrate superior performance as adsorbents for heavy metal ions, boasting higher adsorption capacities and exceptional stability when compared with those prepared hydrothermally. Additionally, they serve as excellent supports of cobalt catalysts for Fischer-Tropsch synthesis, achieving low CH₄ conversion rates and a high olefin/paraffin ratio in C_2-4 products. With its operational simplicity, accessible equipment, rapid synthesis capabilities, and enhanced material properties, MIPEC stands out as a highly promising technique for the efficient production of zeolites, underscoring its extensive potential for widespread applications.