Electron beam Ni-layer deposited LaTiO2N photoanodes for the enhanced photoelectrochemical performance of water oxidation

Improving the photoconversion efficiency of LaTiO
₂
N photoanodes is crucial in the strong oxidizing conditions and in high overpotential of four-electron water oxidation system. It is essential for electrode to improve simultaneously reduce the recombination, photo/chemical corrosion resistivity and optical losses. In our present study, the photoelectrode has been fabricated by homogeneous CoOx co-catalyst aided by impregnation annealing method and coated with an ultrathin Ni layer by electron beam evaporation method (EB). The fabricated electrode was transferred to a three-electrode photoelectrochemical (PEC) cell system and electrodeposited of cobalt-phosphate (Co-Pi) loading as an oxygen evolution (OER) co-catalyst. The CoPi deposition was fixed and variable the Ni-coating and CoOx co-catalysts for optimization the best results of electrode. The optimal 2 nm Ni coating with 3wt% CoOx-co-catalyst loading on electrode, resulted in significantly enhanced the photocurrent and PEC water oxidation performance. The Ni and CoOx-modified LaTiO
₂
N electrode serve as a highly active O
^2-
evolving photoanode achieving 3.7 mA cm
^-2
of the photocurrent density at 1.23V versus reversible hydrogen electrode (V
_rhe
) in 0.2 M K
₂
HPO
₄
solution (adjusted pH 13 by addition of NaOH) under solar simulator irradiation Airmass 1.5 Global (AM 1.5G). The current-voltage was optimized off all modified electrode and found the maximum solar to energy conversion efficiency is 0.61% with IPCE 35% at 480 nm wavelength at 1 V
_rhe
. The maximum amounts of evolved O
₂
and H
₂
were found 16 and 32 μmol for two hours at 1 V
_rhe
of optimal technique CoPi-Ni-modified CoOx-LaTiO
₂
N electrode (CoPi/Ni/Co Ox/LaTiO
₂
N/T a/Ti) respectively. The optical transparency of the ultrathin Ni coating establishing as a particularly advantageous treatment for efficient and stable water oxidation photoanodes.