Sreejivungsa Kaniknun, Kosolwattana Suppanat, Sakulsombat Morakot, Thongbai Prasit
Department of Physics, Faculty of Science, Giant Dielectric and Computational Design Research Group (GD-CDR), Khon Kaen University, Khon Kaen, 40002, Thailand.
Department of Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand.
Sci Rep. 2025 May 23;15(1):18030. doi: 10.1038/s41598-025-03201-6.
Cockle shells served as a sustainable and non-toxic calcium source for CO capture through carbonation-calcination cycles. In this study, CaCO derived from cockle shells was used to synthesize CaCuTiO (CCTO) ceramics via the solid-state reaction method and sintered at 1010-1090 °C. The resulting ceramics exhibited colossal dielectric permittivity (∼ 10 at 1 kHz, 25 °C) and a low dielectric loss (tanδ ≈ 0.04), confirming their suitability for capacitor applications. The high dielectric permittivity was primarily attributed to the internal barrier layer capacitor mechanism, in which insulating grain boundaries separated semiconducting grains, enhancing interfacial polarization. Impedance spectroscopy supported this explanation, while DC bias-dependent dielectric measurements revealed a noticeable decrease in permittivity under applied voltage, indicating that surface barrier layer capacitor effects at the ceramic-electrode interface also contributed to the dielectric behavior. Furthermore, X-ray photoelectron spectroscopy confirmed the presence of oxygen vacancies and hydroxyl groups at the ceramic surface, which facilitated water molecule adsorption and modulated interfacial charge transport. As a result, the CCTO ceramics demonstrated excellent humidity sensing performance, with a fast response time of 0.25 min, a recovery time of 0.45 min, and a low hysteresis error of 2.3%. These findings demonstrate the dual role of cockle shell-derived CaCO as both a sustainable CO sorbent and a valuable precursor for high-performance dielectric and humidity-sensing ceramics.
蚶壳作为一种可持续且无毒的钙源，可通过碳化 - 煅烧循环用于捕获二氧化碳。在本研究中，以蚶壳衍生的碳酸钙为原料，采用固态反应法合成了CaCuTiO（CCTO）陶瓷，并在1010 - 1090°C下烧结。所得陶瓷表现出巨大的介电常数（在1kHz、25°C时约为10）和低介电损耗（tanδ≈0.04），证实了它们适用于电容器应用。高介电常数主要归因于内部势垒层电容器机制，其中绝缘的晶界分隔了半导体晶粒，增强了界面极化。阻抗谱支持了这一解释，而与直流偏压相关的介电测量表明，在施加电压下介电常数显著降低，这表明陶瓷 - 电极界面处的表面势垒层电容器效应也对介电行为有贡献。此外，X射线光电子能谱证实了陶瓷表面存在氧空位和羟基，这促进了水分子吸附并调节了界面电荷传输。结果，CCTO陶瓷表现出优异的湿度传感性能，响应时间为0.25分钟，恢复时间为0.45分钟，滞后误差低至2.3%。这些发现证明了蚶壳衍生的碳酸钙作为可持续的二氧化碳吸附剂以及高性能介电和湿度传感陶瓷的有价值前驱体的双重作用。
