Highly Selective Detection of Large-Sized Chemical Warfare Agents via Interface-Controlled Diffusion Channels of Graphene Oxide Frameworks

Chemical warfare agents (CWAs), which contain organophosphonate groups, are highly toxic compounds designed to inflict harm and death. They have been utilized in both wartime conflicts and acts of terrorism. In response to the persistent threat of CWAs, various organic receptors and high-surface-area matrix materials have been extensively researched. This study investigates how the interlayer spacing of the graphene oxide framework (GOF) with receptors affects its ability to detect a large-sized simulant of CWAs, dimethyl methylphosphonate (DMMP). The interlayer spacing was controlled by the concentration and length of diamine spacers, varying from 7.8 to 10.5 Å. Quartz-crystal microbalance (QCM) and surface acoustic wave (SAW) were employed to conduct a cross-investigation into the sensitivity and selectivity of GOF. The enlarged diffusion channel width of the optimized GOF allows for easy accessibility of DMMP, resulting in over 99% selectivity compared to interfering volatile organic compounds (VOCs), and an 8.7-fold increase in adsorption sensitivity.