Figure 4. Photoelectrochemical behaviours of various photoelectrodes.

(a) Overlaid current–potential curves of the individual photocathodes and photoanodes measured in a three-electrode experiment. C/Ti/p-Si and C/TiO₂/Ti/n⁺p-Si in a 0.05 M AQDS+1.0 M H₂SO₄ solution; while Pt/n-Si and Pt/p⁺n-Si/ in a 0.2 M HBr+1.0 M H₂SO₄ solution. Chronoamperometry of the C/TiO₂/Ti/n⁺p-Si photocathode in a 0.05 M AQDS+1.0 M H₂SO₄ solution (b) and the Pt/p⁺n-Si photoanode in a 0.2 M HBr+1.0 M H₂SO₄ solution (c). The applied stirring speeds were 1,000 r.p.m. in the AQDS solution and 700 r.p.m. in the HBr solution, respectively. Light source: AM 1.5-G 100 mW cm⁻².