Cobalt and Magnetite Functionalized Virus Nanofibers for Hydrogen Generation

The use of virus based materials for nanotechnology applications has increased in recent years owing to their straightforward production, their ability to undergo surface modifications, and their inherently predictable structures. We show that the negatively charged surface of the native fd phage (virus) could facilitate ionic cross-linking via multivalent cobalt ions having opposite charge. Subsequent adsorption of magnetite to the cobalt/phage fibers allowed a high surface area network of cobalt and magnetite which was easily retrievable from solution using a simple magnet. With native fd phage as the template, we demonstrated the room temperature assembly of a cobalt/magnetite/phage nanofiber network. Formation of a catalytically active Co-B coating on the surface of the network structure was achieved by reduction with sodium borohydride. Examining the chemically reduced network, we found it may serve as a catalyst for controlled production of hydrogen gas from sodium borohydride. The embedded magnetite nanoparticles allowed for removal of the catalytic network, which can be of benefit for reactions requiring controlled timing of product formation such as for "on demand" hydrogen generation.