Enhanced photoelectrochemical oxidation of alkali water over cobalt phosphate (Co-Pi) catalyst-modified ZnLaTaON2 photoanodes


Zinc lanthanum tantalum oxynitride [ZnLaTaON2] powders were synthesized by conventional solid state reaction. ZnLaTaON2 photoelectrodes were prepared by electrophoretic deposition of ZnLaTaON2 suspension in acetone onto ITO substrate. The photoelectrodes of ZnLaTaON2 were established to reveal photoelectrochemical properties for water oxidation reaction. Moreover, a cobalt phosphate (Co-Pi) was loaded on ZnLaTaON2 photoelectrodes via photodeposition method to enhance the photoelectrochemical water oxidation performances. Photocurrent voltage characteristics of the Co-Pi/ZnLaTaON2 photoelectrodes were enhanced with its effect which is more evidenced at lower water oxidation potentials. A relatively stable photocurrent density of 5 mA/cm2 at 1.5 V vs RHE was attained with the support of electron donor in alkaline phosphate solution. Comparatively, in Co-Pi/ZnLaTaON2 photoelectrodes, approximately threefold enhancement was noticed at 1.8 VRHE in assessment with parent photoelectrode. On the other hand, Co-Pi/ZnLaTaON2 photoelectrodes have been shown as an alternative pathway to improve the photoelectrochemical current gain through the PEC water oxidation reaction.

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The authors would like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for funding this research group No. RG-1438-087.

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Correspondence to Prabhakarn Arunachalam.

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Shaddad, M.N., Arunachalam, P., Al-Mayouf, A.M. et al. Enhanced photoelectrochemical oxidation of alkali water over cobalt phosphate (Co-Pi) catalyst-modified ZnLaTaON2 photoanodes. Ionics 25, 737–745 (2019). https://doi.org/10.1007/s11581-018-2688-y

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  • Photoelectrochemistry
  • Cobalt phosphate
  • Water oxidation
  • Electrophoresis