Silica Nanochannel Membranes for Electrochemical Analysis and Molecular Sieving: A Comprehensive Review

Silica nanochannel membranes, particularly those consisting of highly ordered and vertically aligned channels (designated as SNM for simplicity in this review), have recently emerged as a class of attractive nanomaterials, because of their controllable and tunable pore structure, large surface area, high selectivity, and permeability, as well as diverse promising applications. This review describes recent developments in the field of SNM and their applications in electrochemical analysis and molecular separation. We summarize and highlight (i) the synthesis and functionalization strategies; (ii) the basic properties with emphasis on the selectivity and permeability, and factors affecting them; (iii) electrochemical analysis based on the electrode-supported SNM in terms of electrostatic, hydrophobic extraction, size-exclusion, and anti-fouling effects; (iv) molecular separation using the flow-through SNM according to molecular properties (size, charge, and lipophilicity) and gated, rectified molecular transport. Finally, we present an outlook and perspective on the further applications of SNM in the relevant fields.