Cu-Deficient Plasmonic Cu2–xS Nanoplate Electrocatalysts for Oxygen Reduction

Cation deficient transition metal sulfides have attracted increased attention due to their unique properties that arise from degenerate p-doping, particularly their localized surface plasmon resonance (LSPR) and related optical properties. Here, we present the first study of their electrocatalytic activity. We developed a facile one-pot method to prepare p-doped copper sulfide nanoplates with tunable LSPR at moderate temperature (below 100 °C) without any hot injection or rapid mixing step. The doping level was controlled by varying the concentration of cation precursor (Cu2+) to finely tune the LSPR wavelength without changing the nanoplate size or morphology. Cu2–xS nanoplates with three different doping levels were tested for their electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline solution. Importantly, increasing the concentration of free holes in Cu2–xS significantly enhanced the ORR catalytic activity. Furthermore, to improve the electrical conductivity, the most heavily ...