Photo Energy-Enhanced Oxygen Reduction and Evolution Kinetics in Zn-Air Batteries
Hange Feng, Chaomin Zhang, Menghao Luo, Yuechuan Hu, Zibo Dong, Shaolin Xue, Paul K. Chu
Abstract
Harvesting solar energy directly to boost the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on an air cathode is a promising approach. Herein, we synthesize a step-scheme (S-scheme) titanium dioxide-indium selenide (TiO 2 -In 2 Se 3 ) heterojunction catalyst. The onset potential in ORR under light illumination reaches 1.28 V and the onset potential decreases to 0.48 V in OER. When an S-scheme TiO 2 -In 2 Se 3 heterojunction is exposed to light, photogenerated electrons at the conduction band (CB) of TiO 2 migrate to the valence band (VB) of In 2 Se 3 due to the built-in electric field. The photogenerated electrons with strong reduction capability on the CB of In 2 Se 3 and the holes with strong oxidation capability on the VB of TiO 2 boost the cathode reaction kinetics (ORR/OER). The excellent outcome reveals tremendous commercial potential of photo-enhanced Zn-air batteries.