Integrated Networks of Mesoporous Silica Nanowires and Their Bifunctional Catalysis-Sorption Application for Oxidative Desulfurization

Integration of nanostructured mesoporous silica and related functional materials into larger assemblages will benefit their applications across various technological fields including heterogeneous catalysis, separation, sensing, drug delivery, and other applications because such assembled nanosilica can be handled in a way similar to conventional materials after use. In this work, we develop a synthetic route to synthesize and integrate thin mesoporous silica nanowires into three-dimensional (3D) networks. Hierarchical pore structures can be attained, respectively, from texture and framework mesopores within the networks. To explore their applicability, the networked nanowires have been used to support molybdenum oxide and tested for oxidative desulfurization (ODS) of model diesels. Because of the highly accessible porosity in this silica architecture, excellent activity for conversion of dibenzothiophene (C12H8S) to dibenzothiophene sulfone (C12H8O2S) has been achieved. Quite surprisingly, the nanowire-based molybdenum catalysts can also serve as effective adsorbents for removal of product compound C12H8O2S. In this regard, the materials system can function integrally both as a catalyst and as an adsorbent for the ODS process. Investigation on the formation of 3D silica nanowires has been conducted by varying synthetic parameters, and robust recyclability of the catalyst adsorbent system has also been demonstrated.