Jump to main content
Jump to site search

Issue 17, 2013
Previous Article Next Article

Solar water oxidation using nickel-borate coupled BiVO4 photoelectrodes

Author affiliations

Abstract

A naturally abundant nickel-borate (Ni–Bi) complex is demonstrated to successfully catalyze the photoelectrochemical (PEC) water oxidation of BiVO4 electrodes at 1.23 VRHE with nearly 100% faradaic efficiency for oxygen evolution. Ni–Bi is electrodeposited (ED) and photodeposited (PD) for varying times on BiVO4 electrodes in the 0.1 M borate electrolyte with 1 mM Ni2+ at pH 9.2. Surprisingly, optimally deposited Ni–Bi films (ED-10 s and PD-30 min) display the same layer thickness of ca. 40 nm. Both Ni–Bi films enhance the photocurrent generation of BiVO4 at 1.23 VRHE by a factor of 3–4 under AM 1.5-light irradiation (100 mW cm−2) along with ca. 250% increase in the incident and absorbed photon-to-current efficiencies. Impedance analysis further reveals that the charge transfer resistance at BiVO4 is markedly decreased by Ni–Bi deposits. The primary role of Ni–Bi has been suggested to be a hole-conductor making photogenerated electrons more mobile and catalyzing a four-hole transfer to water through cyclic changes between the lower and higher Ni oxidation states. However, thick Ni–Bi films (>∼40 nm) significantly reduce the PEC performance of BiVO4 due to the kinetic bottleneck and charge recombination. Under identical PEC conditions (0.1 M, pH 9.2), the borate electrolyte (good proton acceptor) is found to be better than nitrate (poor proton acceptor), indicative of a proton-coupled electron transfer pathway in PEC water oxidation.

Graphical abstract: Solar water oxidation using nickel-borate coupled BiVO4 photoelectrodes

Back to tab navigation

Supplementary files

Publication details

The article was received on 08 Jan 2013, accepted on 25 Feb 2013 and first published on 25 Feb 2013


Article type: Paper
DOI: 10.1039/C3CP00073G
Phys. Chem. Chem. Phys., 2013,15, 6499-6507

  •   Request permissions

    Solar water oxidation using nickel-borate coupled BiVO4 photoelectrodes

    S. K. Choi, W. Choi and H. Park, Phys. Chem. Chem. Phys., 2013, 15, 6499
    DOI: 10.1039/C3CP00073G

Search articles by author

Spotlight

Advertisements