Outstanding hydrogen evolution performance of supported Pt nanoparticles: Incorporation of preformed colloids into mesoporous carbon films

Abstract

Platinum is the best catalyst known so far for the hydrogen evolution reaction (HER) in acidic environments, but it is also a scarce and expensive resource. Maximizing its performance per metal atom is essential in order to reduce costs. The deposition of small Pt nanoparticles (2–3 nm) onto electrically conductive, highly accessible and stable carbon supports leads to active catalysts. However, blocking of pores and active sites by Nafion, which acts as a binding species, reduces the catalytic activity. Moreover, inaccessible Pt located in micropores diminishes an efficient exploitation of the noble metal.We report a new synthesis approach to ordered mesoporous carbon (OMC) coatings with preformed Pt nanoparticles. The particles are exclusively located inside the mesopores. Furthermore, no Nafion binder is needed. As a consequence, the PtNP/OMC catalyst film outperforms Pt/C catalysts reported in literature particularly at high current densities. PtNP/OMC catalyst films with a geometric Pt loading of 1.6 µgPt/cm2 achieve a current density of −100 mA/cm2 at an overpotential of ca. −70 mV.