Nanostructuring the surface of silicon substrates for photoelectrochemical reduction of protons (i.e., water splitting) affords many benefits compared to planar silicon. Recently, nanoporous silicon (also called “<i>black</i> silicon”) has been shown to both (1) mitigate reflective losses of incoming light and (2) promote rapid bubble evolution, eliminating the need for surfactants in the electrolyte. In addition, the increased surface area yields better kinetics for hydrogen production, decreasing the over-potential required to reduce protons. Incorporating hydrogen production catalysts onto black silicon surfaces further reduces the kinetic barrier for hydrogen production. For example, burying platinum nanoparticles in the nanopores of black silicon reduces the onset potential required to reduce protons while simultaneously protecting the catalytically active surface sites from oxidation. In this presentation, we will detail the chemistry at the platinum nanoparticle catalyst/black silicon interface that affords the reduced onset potential for proton reduction and high stability of this system toward oxidative degradation. We will also discuss the unique ability of black silicon to serve as a potential universal photoelectrode for both inorganic and bio-inspired HER catalysts.

Exploring the potential of nanostructured black silicon toward catalyst-assisted photoelectrochemical reduction of water

249th National Meeting (2015)

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