High‐Capacitance Nanoporous Noble Metal Thin Films via Reduction of Sputtered Metal Oxides

Increasing the electrochemical surface area of noble metal electrodes is vital for many applications, including catalysis and bioelectronics. Herein, a method is presented for obtaining porous noble metal thin films via reactive magnetron sputtering of noble metal oxides, MOx, followed by their reduction using chemical reducers or electrochemical current. Variation of reduction conditions yields a range of different electrochemical and morphological properties. This method for obtaining porous noble metals is rapid, facile, and compatible with microfabrication processes. The resulting metallic films are porous and have competitively high capacitance and low impedance.