Plasmon coupling inside 2D-like TiB2 flakes for water splitting half reactions enhancement in acidic and alkaline conditions

Hybridization of catalytic and plasmon active materials provides an elegant way for efficiently improving of photo-electrochemical (PEC) water splitting. In this work, we propose the utilization of the plasmon coupling between surface plasmon polariton (SPP) and localized surface plasmon (LSP) for gigantic light concentration and triggering of the catalytic activity of titanium diboride (TiB2) flakes. The enhancement of TiB2 flakes' catalytic activity as a result of coupled plasmon triggering was investigated in PEC, including hydrogen and oxygen evolution half-reactions (HER and OER) performed in alkaline and acidic conditions. Additional studies performed at various light wavelengths and the time-dependent response of the structure show that the catalytic activity is triggered through the excitation of electron-hole pairs in TiB2 and their subsequent separation/acceleration in strong coupled plasmons field. In general, our work provides one of the first attempts how to realize a symmetric and less pH-sensitive catalyst for PEC water splitting.