Warty Akash, Chen Amy, Tran Dat T, Kraus Harrison, Woehl Taylor J, Liu Dongxia
Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware DE 19716, United States.
Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States.
JACS Au. 2024 Dec 10;4(12):4769-4779. doi: 10.1021/jacsau.4c00691. eCollection 2024 Dec 23.
Zeolite coatings are studied as molecular sieves for membrane separation, membrane reactors, and chemical sensor applications. They are also studied as anticorrosive films for metals and alloys, antimicrobial and hydrophobic films for heating, ventilation, and air conditioning, and dielectrics for semiconductor applications. Zeolite coatings are synthesized by hydrothermal, ionothermal, and dry-gel conversion approaches, which require high process temperatures and lengthy times (ranging from hours to days). Here, we report the first zeolite coatings synthesized via electrochemical deposition on a cathodic electrode, with controlled crystal polymorphism achieved within subhourly duration. We demonstrate this approach by developing sodium zeolite (e.g., sodalite (SOD), NaA (LTA), and Linde Type N (LTN)) coatings on a titanium electrode and extending the synthesis method to porous stainless steel. The coating morphology and crystallinity depend on the temperature, time, and applied current. The coating thickness is independent of the applied current, showing the presence of a self-regulating mechanism to ensure a uniform coating thickness across the metal surface. The electrochemical zeolite growth mechanism was elucidated with high-resolution transmission electron microscopy, and applications of the resultant zeolite coatings for oil/water separation and ethanol/water pervaporation were exploited. Electrochemical synthesis represents a novel, simple, fast, and environmentally friendly approach to preparing zeolite coatings. It can potentially be generalized for developing zeolite materials with diverse framework structures, morphologies, and orientations for substrates with complicated geometries.
沸石涂层作为用于膜分离、膜反应器及化学传感器应用的分子筛受到研究。它们还作为金属和合金的防腐膜、用于供暖、通风和空调的抗菌及疏水膜以及半导体应用的电介质受到研究。沸石涂层通过水热法、离子热法和干凝胶转化法合成，这些方法需要较高的工艺温度和较长的时间（从数小时到数天不等）。在此，我们报告了首次通过电化学沉积在阴极电极上合成的沸石涂层，在不到一小时的时间内实现了可控的晶体多晶型。我们通过在钛电极上制备钠沸石（如方钠石（SOD）、NaA（LTA）和林德型N（LTN））涂层并将合成方法扩展到多孔不锈钢来证明这种方法。涂层的形态和结晶度取决于温度、时间和施加的电流。涂层厚度与施加的电流无关，表明存在一种自调节机制以确保整个金属表面的涂层厚度均匀。利用高分辨率透射电子显微镜阐明了电化学沸石生长机制，并开发了所得沸石涂层在油/水分离和乙醇/水渗透蒸发方面的应用。电化学合成代表了一种制备沸石涂层的新颖、简单、快速且环保的方法。它有可能被推广用于为具有复杂几何形状的基材开发具有不同骨架结构、形态和取向的沸石材料。
