Cathodic shift in onset potential of hematite photoanodes by ZrO2 underlayer for efficient water splitting = Cathodic shift in onset potential of hematite photoanodes by ZrO2 underlayer for efficient water splitting

다국어 초록 (Multilingual Abstract)

Herein we report that influence of Zr underlayer to hematite photoanodes for cathodic shift in onset potential as well as photocurrent. Akaganite (β-FeOOH) nanorods were grown on Zr underlayer treated FTO substrates. Sintering at 800°C transforms the akaganite to hematite phase and induces the Sn atoms from the FTO substrates will penetrate in to the hematite lattices along with Zr atoms. Zr underlayer treated sample shows the better performance of water splitting compared to the pristine photoanode. Cathodic shift in onset potential as well as photocurrent was done by penetration of Zr atoms from the underlayer to hematite lattices. 0.96 mA/cm2 at 1.23 VRHE was achieved for Zr based hematite photoanode with low turn on voltage 0.7 V vs. RHE. The crystalline structure and morphology for the Zr modified hematite photoanode almost identical to the pristine photoanode. Presence of Zirconium and Sn diffusion from the FTO were confirmed by XPS analysis. Electrochemical Impedance Spectroscopy reveals that the presence of Zr underlayer increases the charge transfer resistance along the various interfaces. The presence of ZrO2 underlayer decreases the FTO deformation and the sheet resistance of FTO is decreased. Mott Schottky analysis reveals that the donor density and flat band potential of the pristine and Zr underlayer treated photoanodes shows similar values. This is the first report on Zr underlayer based hematite photoanodes for the increment in photocurrent and cathodic shift in onset potential.