Immobilization of Photocatalysts on Spider Silk-Based Membranes for Continuous Hydrogen Production

The demand for green and sustainable energy sources is rapidly increasing. Hydrogen is an emission-less energy source, but current production methods are energy-consuming, making hydrogen in part unattractive compared to conventional energy sources. However, photocatalytic hydrogen production, which harnesses solar energy to produce hydrogen as an energy storage medium, is a promising approach in this context. Typically, inorganic materials provided as nanoparticles are used as catalysts in this process but pose challenges concerning recycling and reuse. Further, the immobilization of the nanoparticles is necessary to allow the large-scale application for hydrogen production. Due to its extraordinary mechanical properties, biodegradability, and ability for genetic modification, recombinant spider silk is a promising material for the immobilization of nanoparticles. Here, hybrid membranes have been developed based on electrospun meshes made of modified spider silk proteins and immobilized gold-modified TiO₂-nanoparticles (Au@TiO₂-NPs). These membranes showed photocatalytic activity and were capable of producing hydrogen. Additionally, the particle-loaded membranes were tested in a flow-through system, offering the possibility for on-demand hydrogen production.