CaBi6O10: a novel promising photoanode for photoelectrochemical water oxidation

Abstract

Novel CaBi₆O₁₀ films were prepared via a simple dip-coating method and applied as a photoanode in photoelectrochemical (PEC) water splitting for the first time. Herein, the detailed growth mechanism of CaBi₆O₁₀ has been discussed. The optical absorption of CaBi₆O₁₀ was also investigated, and the results indicated that its ideal band-gap energy (∼2.3 eV) causes it to respond to visible light. Additionally, the morphology and thickness of the films were characterized in detail. PEC measurements showed that this CaBi₆O₁₀ photoanode exhibits high photoelectrochemical activity based on the optimal pH value of the precursor solution and thickness of the film; its photocurrent density is as high as 0.39 mA cm⁻² at 1.23 V vs. RHE under simulated sunlight. Moreover, the CaBi₆O₁₀ photoelectrode displays a very stable photoelectric property under illumination. The excellent PEC performance is attributed to the excellent light absorbance, broad photoresponse range, and efficient photogenerated electron–hole pair separation of CaBi₆O₁₀. These results demonstrate that CaBi₆O₁₀ is a promising photoanode for solar water splitting.