Indium oxide nanoflakes/cerium oxide nanoclusters composites for improving sustained photocathodic protection under light and darkness
Xiaoying Zhang, Yuehua Chen, Zuquan Jin, Haosen Jiang, Xiaoqing Wang
Abstract
The hazards of metal corrosion and the shortcomings of photoelectric cathodic protection pose a major challenge to metal protection under dark conditions. Thus, In 2 O 3 nanoflakes/CeO 2 nanoclusters composites were prepared and their photocathodic protection (PCP) performance for 304 SS was studied in 3.5 wt% NaCl solution under light and darkness, respectively. Under illumination, the self-corrosion potential of 304 SS coupled with In 2 O 3 /CeO 2 decreased by 180 mV, and the corresponding current density was 2.13 and 170 times higher than that of In 2 O 3 and CeO 2 , respectively. In the darkness, In 2 O 3 /CeO 2 remained current density of 10 μA cm −2 and protect 304 SS for 4.7 h. The enhanced PCP performance can be contributed to the introduction of the In 2 O 3 /CeO 2 heterojunction , which extends the light absorption range, facilitates the transfer and separation of the photocarriers, resulting in more effective electron aggregation on 304 SS. Furthermore, the oxidation-reduction of Ce 4+ /Ce 3+ with charge storage is response for the dark state protection performance of In 2 O 3 /CeO 2 heterojunction . The photogenerated electrons are stored by a reduction reaction of Ce 4+ /Ce 3+ under illumination, while in the dark state these stored electrons will release through the oxidation reaction of Ce 3+ /Ce 4+ . This work would be a reference for the application in metal corrosion protection under dark conditions.