Effect of annealing of β-Bi2O3 over enhanced photoelectrochemical performance

In-depth investigation was carried out to determine the relationship between morphological, structural conversion, and photoelectmchemical (PEC) performance of beta-Bi2O3 nanostructured thin film annealed at temperatures ranging from 500 degrees C to 650 degrees C. Apart from the phase transformation it has also been observed that the basic nanostructure were converted from nanoflakes to nanoworms via nanomds. Transformation that occurs in the basic beta-Bi2O3 leads to the emergence of new non-stoichiometric Bi2O2.33 due to the fast annealing at 600 degrees C which enhance the oxygen vacancies in the beta-Bi2O3/Bi2O2.33 heterojunction as analyzed by the XRD and XPS. The annealing within the range (500 degrees C-650 degrees C) results in the red shifting in the optical band gap. Consequence of the annealing up to 600 degrees C enhanced the photocurrent density up to ( 1.53 mAcm(-2) at 1.2 V vs RHE) which shows 1.7 times higher than basic beta-Bi2O3 f 0.90 mAcm(-2) at 1.2 V vs RHE) in the Na2SO3 electrolyte. However in the neutral Na2SO4 electrolyte the photocurrent density of beta-Bi2O3 at 600 degrees C was found ( 0.21 mAcm(-2), 1.23 V vs RHE) which shows 2.6 times higher than basic beta-Bi2O3 f 0.08 mAcm(-2), 1.23 V vs RHE). Beyond this shifting in the onset potential for all the samples were found on altering electrolyte from Na2SO4 (pH = 7) to Na2SO3 (pH = 9). The Mott-Schottky and EIS were demonstrated for scrutinizing the charge kinetics for all the photoelectrodes. These results contribute a favorable impact of annealing over the structure and the morphology of the material which can produce high PEC ability.

Automated summary

An in-depth investigation was conducted to explore the relationship between the structure and morphology of beta-Bi2O3 nanostructured thin film annealed at different temperatures and its photoelectrochemical (PEC) performance. It was found that annealing caused significant changes in the nanostructure and the formation of a new non-stoichiometric phase (Bi2O2.33). Annealing at specific temperatures resulted in improved photocurrent density and enhanced PEC efficiency. These findings contribute to a better understanding and improvement of the PEC performance of beta-Bi2O3.