ATR-SEIRAS Investigation of the Fermi Level of Pt Cocatalyst on a GaN Photocatalyst for Hydrogen Evolution under Irradiation

The interaction of photogenerated carries in GaN photocatalyst with Pt cocatalyst for hydrogen evolution under irradiation was investigated from in situ ATR-SEIRAS measurement by following the CO vibrational frequency. After irradiation, the CO frequency shifted higher, indicating that the Fermi Level of Pt particles was positively shifted by the photogenerated holes. Thereafter, a Lower frequency peak appeared, indicating that the Fermi level of some Pt particles was negatively shifted to the hydrogen evolution potential by photogenerated electrons, which is the essential function of cocatalysis for hydrogen evolution.