Achieving both high onset potential and photocurrent in photoelectrodes is a key challenge while performing unassisted overall water splitting using tandem devices. We propose a simple interface modification strategy to maximize the performance of polycrystalline Sb2Se3 photocathodes for photoelectrochemical (PEC) water splitting. The para-aminobenzoic acid (PABA) modification at Sb2Se3/TiO2 interface enhanced both the onset potential and photocurrent of the Sb2Se3 photocathodes. The surface defects in the polycrystalline Sb2Se3 limited the photovoltage production, lowering the onset potential of the photocathode. Surface restoration using the conjugated PABA molecules efficiently passivated the surface defects on the Sb2Se3 and enabled the rapid photoelectron transport from the Sb2Se3 to the TiO2 layer. The PABA treated Sb2Se3 photocathode exhibited substantially improved PEC performance; the onset potential increased from 0.35 to 0.50 V compared to the reversible hydrogen electrode (VRHE), and the photocurrent density increased from 24 to 35 mA cm−2 at 0 VRHE.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation (NRF) of Korea grant (No. 2012R1A3A2026417 ) and the Creative Materials Discovery Program ( NRF-2018M3D1A1058793 ) funded by the Ministry of Science and ICT , and the UK's Engineering and Physical Sciences Research Council (EPSRC) grant EP/N010457/1 . This work was also supported by the Technology Innovation Program - Alchemist Project (No. 20012315 ) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea) .
All Science Journal Classification (ASJC) codes
- Environmental Science(all)
- Process Chemistry and Technology