Graphene Based Framework Materials as Self-Sterilizing Multi-Pollutant Air Filtration Media

The Covid-19 pandemic brought new attention to the extensive harm that airborne micro-organisms can cause to our health and society. However, conventional air filtration media are designed for the removal of particles and are not suitable for the indefinite inactivation of micro-organisms and, under the humid conditions, can even act as a host for their proliferation.^[1] Air disinfection systems like UV-C devices on the other hand require a constant power supply and an additional filter for particles. Thus, they are more expensive to integrate and operate. Therefore, a demand for new air filter materials, that can reliably solve these issues, arises.<br/>A promising approach is air filtration by 3D-assemblies of conductive 2D-nanomaterials.^[2] Recently presented hierarchical graphene framework materials with tailorable structural properties^[3] as well a high conductivity and low heat capacity can be joule-heated to high temperatures (~400 °C) extremely fast at low power consumption.^[4]These materials offer great potential as air filtration media that could sterilize themselves via joule-heating, while being also highly adaptive to individual use cases because of their easily modifiable porosity and geometry.<br/>In this work the utilisation of large-scale graphene framework materials as self-sterilizing air filtration elements for the removal of various pollutants from air is presented. Using an integrated setup generating an aerosol of both, micro-particles and micro-organisms simultaneously, the ability of the framework structures to capture these pollutants can be shown. The filter elements can be homogenously heated via joule-heating to &gt;300 °C for minutes without degradation, even after hundreds of cycles. This heating procedure reliably sterilizes all micro-organisms captured inside the material. Furthermore, it will be shown, that the unique electronic and thermal properties of the 2D-materials incorporated in the framework structures can be used for additional smart features in a final air filtration device. Finally, the utilization of other conductive 2D nanomaterials such as MXenes and their chemical functionalization can allow for an even broader range of applicable pollutants like for example VOCs.<br/><br/>[1] International Journal of Hygiene and Environmental Health, 203, Issues 5–6, <b>2001</b>, 401-409<br/>[2] ACS Nano <b>2019, </b><i>13</i> (10), 11912-11920<br/>[3] ACS Appl. Mater. Interfaces <b>2019</b>, 11, 47, 44652–44663<br/>[4] Materials Today <b>2021</b>, 48, 7-17