Fabrication of CQDs-loaded FeOOH/Cu2O Nanowires for Improvement in Solar Hydrogen Application
Po-Yang Peng1*, Yan-Gu Lin1, Hsin-Yi Lee1, Yu-Chang Lin1
1Materials Science Group, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
2Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan
* Presenter:Po-Yang Peng, email:peng.py@nsrrc.org.tw
We present a active photocathode for solar H2 production, consisting a stable P-type cuprous oxide (Cu2O) photoelectrode has been fabricated by direct galvanostatic electrodeposition of the Cu foil substrate. After coating a nanolayers of N-type Iron oxide-hydroxide (FeOOH), treatment to introduce the p-n junction is beneficial protecting Cu2O from self-photo corrosion and providing short diffusion paths for electron-hole pairs. Following to introduce the Carbon Quantum Dots(CQDs) on the surface, helps to separate the photoinduced charge pairs by attracting electrons, to facilitate the interfacial electron transfer. The crystalline, surface morphology, and structure of the CQDs/FeOOH/Cu2O were characterized by XRD, SEM, and XAS. Results showed that the CQDs/FeOOH/Cu2O were dominated by Cu2O phase. XAS finding confirmed XRD results that the copper element in CQDs/FeOOH/Cu2O was Cu (I) instead of Cu (II). After CQDs and FeOOH introducing, the Cu2O nanowires structure kept its integrity with no significant morphological change, which was beneficial for photoelectrochemical (PEC) performance applications. Results in the best performance case electrodes showed photocurrents of CQDs/FeOOH/Cu2O (-2.5 mA/cm2), exhibited a low external Bias at 0.2 V RHE but an almost identical photocurrent. Under 0.70 V RHE bias potential, generated a relatively small positive shift in onset potential. CQDs and FeOOH can be assisted generates more electron and hole. Successfully prove the in-situ of charge transfer between the interface by XAS under AM 1.5 G filter illumination. The improvement in PEC efficiency by introducing the CQDs and FeOOH material can be regarded as a suitable hetero partner, it provides useful insights into the development of photoelectrode with water splitting.

Keywords: Photoelectrochemical, Water splitting, Cuprous oxide, Iron oxide-hydroxide, Synchrotron radiation