One-step preparation of optically transparent Ni-Fe oxide film electrocatalyst for oxygen evolution reaction

• Published in: Electrochimica acta 2015-07, Vol.169, p.402-408
• Main Authors: Zhang, Doudou, Meng, Lijian, Shi, Jingying, Wang, Nan, Liu, Shengzhong, Li, Can
• Format: Article
• Language: English
• Subjects: Ni-Fe oxide; Optically transparent; Oxygen evolution reaction; Thin film electrocatalyst
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2015.04.101

The optically transparent Ni-Fe oxide films are deposited on FTO substrates by one-step reactive magnetron co-sputtering. The optimal electrocatalytic activity for oxygen evolution reaction is achieved at an atomic ratio of Fe/Ni=3:7, which is a very promising cocatalyst for photoelectrochemical water splitting owing to its optical transparency and high electrochemical activity. [Display omitted] Optically transparent cocatalyst film materials is very desirable for improved photoelectrochemical (PEC) oxygen evolution reaction (OER) over light harvesting photoelectrodes which require the exciting light to irradiate through the cocatalyst side, i.e., front-side illumination. In view of the reaction overpotential at electrode/electrolyte interface, the OER electrocatalysts have been extensively used as cocatalysts for PEC water oxidation on photoanode. In this work, the feasibility of a one-step fabrication of the transparent thin film catalyst for efficient electrochemical OER is investigated. The Ni-Fe bimetal oxide films, ∼ 200nm in thickness, are used for study. Using a reactive magnetron co-sputtering technique, transparent (> 50% in wavelength range 500-2000nm) Ni-Fe oxide films with high electrocatalytic activities were successfully prepared at room temperature. Upon optimization, the as-prepared bimetal oxide film with atomic ratio of Fe/Ni=3:7 demonstrates the lowest overpotential for the OER in aqueous KOH solution, as low as 329mV at current density of 2mAcm−2, which is 135 and 108mV lower than that of as-sputtered FeOx and NiOx thin films, respectively. It appears that this fabrication strategy is very promising to deposit optically transparent cocatalyst films on photoabsorbers for efficient PEC water splitting.