Effect of morphology on the photoelectrochemical performance of nanostructured Cu2O photocathodes

Lian C T Shoute; Kazi M Alam; Ehsan Vahidzadeh; Ajay P Manuel; Sheng Zeng; Pawan Kumar; Piyush Kar; Karthik Shankar

doi:10.1088/1361-6528/aba2a3

Effect of morphology on the photoelectrochemical performance of nanostructured Cu₂O photocathodes

Nanotechnology. 2021 Jun 21;32(37). doi: 10.1088/1361-6528/aba2a3.

Authors

Lian C T Shoute¹, Kazi M Alam¹, Ehsan Vahidzadeh¹, Ajay P Manuel¹, Sheng Zeng¹, Pawan Kumar¹, Piyush Kar¹, Karthik Shankar¹

Affiliation

¹ Department of Electrical and Computer Engineering, University of Alberta, 9211 - 116 St, Edmonton, Alberta T6G 1H9, Canada.

PMID: 32619996
DOI: 10.1088/1361-6528/aba2a3

Abstract

Cu₂O is a promising earth-abundant semiconductor photocathode for sunlight-driven water splitting. Characterization results are presented to show how the photocurrent density (J_ph), onset potential (E_onset), band edges, carrier density (N_A), and interfacial charge transfer resistance (R_ct) are affected by the morphology and method used to deposit Cu₂O on a copper foil. Mesoscopic and planar morphologies exhibit large differences in the values ofN_AandR_ct. However, these differences are not observed to translate to other photocatalytic properties of Cu₂O. Mesoscopic and planar morphologies exhibit similar bandgap (e.g.) and flat band potential (E_fb) values of 1.93 ± 0.04 eV and 0.48 ± 0.06 eV respectively.E_onsetof 0.48 ± 0.04 eV obtained for these systems is close to theE_fbindicating negligible water reduction overpotential. Electrochemically deposited planar Cu₂O provides the highest photocurrent density of 5.0 mA cm^-2at 0 V vs reversible hydrogen electrode (RHE) of all the morphologies studied. The photocurrent densities observed in this study are among the highest reported values for bare Cu₂O photocathodes.

Keywords: PEC devices; electrochemical impedance spectroscopy; electron-hole pairs; nanostructured copper oxide; p-type metal oxide; solar fuels; visible light harvesting.