Insights into electrolyte effects on photoactivities of dye-sensitized photoelectrochemical cells for water splitting

Dye-sensitized photoelectrochemical cell (DS-PEC) is an especially attractive method to generate hydrogen via visible light driven water splitting. Electrolyte, an essential component of DS-PEC, plays a great role in determining the photoactivities of devices for water splitting. When using phosphate buffer (pH   =   6.4) as electrolyte, the DS-PEC displayed much higher photoactivity than using 0.1   M Na 2 SO 4 (pH   =   6.4) as electrolyte. The insight is phosphate anion gathers together to form a negative electrostatic field on TiO 2 surface, which increases the resistance in the TiO 2 /catalyst and electrolyte interface and validly reduces the charge recombination from TiO 2 to the oxidized catalyst.