Effect of gold underlayer on copper(I) oxide photocathode performance
- PDF / 517,666 Bytes
- 9 Pages / 584.957 x 782.986 pts Page_size
- 49 Downloads / 192 Views
Colton Mundt Department of Aerospace Engineering, Iowa State University, Ames, IA 50011, USA
Minh Tran Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
Sonal Padalkara) Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA; and Microelectronics Research Center, Iowa State University, Ames, IA 50011, USA (Received 28 December 2016; accepted 28 March 2017)
Copper(I) oxide (Cu2O) is a very favorable p-type semiconductor. It is an appealing candidate for photoelectrochemical water splitting. Here we report the fabrication and performance of gold (Au) underlayer–Cu2O composite photocathode for photoelectrochemical water splitting. The composite photocathode was fabricated by the electrodeposition technique. The different morphologies of the Au underlayer were achieved via variation in the process parameters including applied potential, electrolyte pH, and the presence of L-cysteine in the electrolyte. The Cu2O overlayer was also deposited using electrodeposition. Additionally, the influence of morphology variation, of the Au underlayer, on the performance of the composite photocathode was evaluated. It was observed that the performance of the composite photocathode increased by 81% when compared to a control sample of Cu2O. The composite photocathodes were characterized by scanning electron microscopy, X-ray diffraction, and electrochemical impedance spectroscopy.
I. INTRODUCTION
The energy demand in the past decades has significantly increased due to the industrial development in many countries throughout the world. This has led to the increase in consumption of conventional energy resources including fossil fuel and oil. Additionally, this consumption has posed many environmental and health related threats. To overcome these problems, researchers have seriously invested in creating a clean and sustainable energy system. The production of hydrogen via photoelectrochemical (PEC) water splitting is considered as a clean and environmentally friendly fuel, which is formed with the help of a renewable source like sunlight. Here the natural resource, which is water, is also widely available. Thus PEC water splitting for the production of hydrogen has a promising future.1–13 Copper(I) oxide (Cu2O) is a p-type semiconductor with a direct band gap of 2 eV. The energy band levels of Cu2O are favorably positioned to effectively split water under solar irradiation. The conduction band level of Cu2O lies Contributing Editor: Xiaobo Chen a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2017.130
0.7 V negative to the hydrogen evolution potential and the valence band position lies positive to the oxygen evolution potential. Due to the position of the energy band levels, a small overpotential is required to drive the half-cell reaction for water oxidation. Additionally, Cu2O has a theoretical solar-to-fuel conversion efficiency of 18%.14 Moreover, Cu2O is an inexpensive, abundantly available material and can be fabricated by simple,
Data Loading...
