Stable surface functionalization of carbonized mesoporous silicon†
Mesoporous silicon (PSi) is an emerging nanomaterial studied in e.g. biomedical, sensor and energy applications. In many applications, a major obstacle in its commercial use is the instability of its surfaces, especially when functionalized with organic molecules. In the present work, we introduce a surface functionalization method for PSi, in which carbonized surface of silicon is functionalized with terminal alkenes. A good surface coverage of 0.3 molecules per nm2 was achieved and the material showed excellent aqueous stability at low and neutral pH. It also withstood a highly basic solution for several days. The developed method was used to graft bisphosphonates on the surface and the material was used for metal adsorption. Because of its excellent stability, the adsorbent material lasted up to 50 adsorption/desorption cycles without a significant deterioration of its performance.