Photoelectrochemical Water Oxidation with Plasmonic Au@MnOx Core–Shell Nanoparticles

Development of robust and efficient photocatalytic constructs to facilitate the water oxidation reaction (WOR) remains essential for various renewable energy technologies. Here we report on developing Au@MnOx core–shell nanoparticles that perform the electrochemical WOR at a low onset overpotential requirement of approximately 230 mV. Under visible light excitation, the WOR activity of the Au@MnOx catalytic construct showed further improvement with the decrease of the overpotential requirement and generation of a photocurrent of 128 μA/cm2 at 1 V applied potential. The incident photon to photocurrent conversion efficiency (IPCE) was found to be 0.1%. The Au@MnOx core–shell nanoparticles were also found to be stable under prolonged photoexcitation up to 2000 s.