Background
Hydrogen and other fuels can be produced by living bio-nano systems which combine microorganisms and nanomaterials. Typically, these systems use light absorbed by nanomaterials to provide high-energy electrons (via an electron transfer process) for microbial metabolic processes yielding a biosynthetic solar fuel such as hydrogen. However, this strategy is limited to the microorganism’s natural metabolic products or requires additional genetic engineering, which can place strain on the organism. Thus, the amount of hydrogen produced from this approach is relatively low.
Technology Overview
This technology flips the standard process and uses the electrons from electrogenic bacteria to directly fuel photocatalytic hydrogen production by nanoparticles. The electrogenic bacteria naturally provide electrons to the nanoparticles through respiration, enabling hydrogen production driven by visible light. This approach has the potential to capitalize on the excellent photocatalytic properties of nanomaterials, which we have shown to be state-of-the-art in terms of efficiency, longevity, and activity. Unlike fuels produced from microbial electrolysis cells, this system requires no external potential. Illuminating the system at 530 nm yields continuous H2 generation for >164 hours, which can be lengthened further by replenishing bacterial nutrients.
Benefits
This system leverages the self-repair and growth of microorganisms in order to fully take advantage of the outstanding photocatalytic properties of nanomaterials. Given the high tunability of nanocrystalline photocatalysts, this method promises a sustainable and flexible route to a variety of solar fuels in the future since the catalytic reaction is governed by the nanomaterial rather than the microbial metabolism.
Applications
Light-driven hydrogen production