Single Crystal, Cuprous Oxide Nanowire Arrays for Highly Stable Photocathodic Water Splitting

Sunday, 5 October 2014: 13:20
Sunrise, 2nd Floor, Mars 1-4 (Moon Palace Resort)
S. Banerjee, F. Wu, Y. Myung (Washington University in St.Louis), and P. Banerjee (Washington University in St. Louis)
Cuprous oxide (Cu2O) is a favorable material for solar water splitting because of its suitable band gap for solar energy absorption (2.2eV) and conduction and valence band edges which straddle the hydrogen and oxygen reduction potentials, respectively. Further, Cu2O is earth abundant and can be synthesized by a variety of techniques. However, Cu2O has its reduction potential within its band edges, leading to considerable photocorrosion and degradation. Thus, there is a pressing need for the fabrication of stable and efficient Cu2O photocathodes. 

Here, we investigate the photoelectrochemical (PEC) properties and stability of dense (108 cm-1) single crystalline Cu2O nanowire (NW) arrays grown by a combination of thermal and carbo-thermal reduction method from pristine copper foils (Fig 1a-d). Our data shows that single crystalline Cu2O NW arrays, show good photoresponse (Fig 1e) and higher stability as compared to thin film Cu2O (Fig 1f,g).

We will present structural investigation of the Cu2O NWs using SEM, HRTEM and Raman spectroscopy (Fig. 1a-d). Photoelectrochemical activity of Cu2O NW arrays for water splitting will be reported and stability towards photocorrosion will be tested with extended and accelerated reliability tests.