Periodic mesoporous organosilicas (PMOs): From synthesis strategies to applications

Since the first reports of periodic mesoporous organosilicas (PMOs) in 1999, this class of materials has attracted more and more attention. In general, such ordered templated mesoporous organosilicas are synthesized via the hydrolysis and co-condensation of bifunctional organosiloxane precursors, also referred to as bridged silsesquioxanes, in the presence of a structure directing agent (SDA) in either an acidic or alkaline environment. The uniqueness of PMO materials that combine the advantages of numerous organic functionalities with the outstanding characteristics of porous inorganic frameworks makes them a powerful toolbox for unlimited applications in multiple fields. Here, we will give a comprehensive review in this field by emphasizing the recent advances that have been achieved concerning their synthesis, morphology, functionalities, and applications mainly after 2014. In the final section, we pay a special attention to research that deals with the design, synthesis and application of a new family of PMOs denoted as hollow spherical and hollow/yolk shell periodic mesoporous organosilicas which display additional benefits as compared with traditional PMOs.