Novel tape-cast SiOC-based porous ceramic electrode materials for potential application in bioelectrochemical systems

One alternative to improve electrochemical performance and long-term applicability in microbial bioelectrochemical systems (BESs) is the use of porous
ceramic electrodes. In this work, electrodes of polymer-derived ceramics based on poly(silsesquioxanes) are synthesized, tailoring the properties by varying pyrolysis temperatures and incorporating conductive phases. Carbon (graphite, carbon black) and metal-based (stainless steel/Cu grids, Co/Ni particles) materials are incorporated into the silicon oxycarbide (SiOC) matrix. The influence of pyrolysis temperature and incorporation of conductive materials on functional properties and electrical conductivity is discussed. Furthermore, this study provides the first investigation of biofilm development on SiOC-based ceramic surfaces with Escherichia coli and Bacillus cereus. SiOC-based ceramics with DC conductivity values at room temperature in the semiconductor range (0.044–0.385 S cm-1) were obtained, with the highest values achieved by Co and Ni particles incorporation and in situ formation of CNTs. Adjustment in hydrophilicity and specific surface areas (6.21–263.45 m2 g-1) is realized by the pyrolysis. The biofilm studies reveal adhesion in the first 2 h for most of the surfaces, with higher bacterial adhesion and biofilm formation with the E. coli. The biocompatibility in terms of bacterial attachment and conductivity values comparable to a commercial carbon felt support the applicability of the developed SiOC-based materials as promising new class of electrodes for BES.