Search

n/n/n triple heterojunction photoanodes made up of Zr:W-BiVO 4 , Fe 2 O 3 , and ZnFe 2 O 4 metal oxides are fabricated through a simplistic spray pyrolysis method. Use of Zr and W as dopants in BiVO 4 plays an important role as Zr increases the carrier density and W reduces the charge recombination. Further, Fe 2 O 3 and ZnFe 2 O 4 serve as a protective layer for Zr:W-BiVO 4 , which augmented the photoelectrochemical performance and achieved a 1.90% conversion efficiency in the triple heterojunction. XRD measurements display the crystalline nature and reduction in particle size due to strain in the sample, UV-vis absorbance shows an extended absorption towards the visible region and the FE-SEM imaging confirms the successful deposition of ZnFe 2 O 4 over BiVO 4 /Fe 2 O 3 . By analyzing the band edge position, it was observed that on formation, the triple heterojunction not only suppresses the charge carrier recombination but also utilizes the band edge offset for the water splitting reaction using solar energy., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The present study is a comparative account of Fe 2 O 3 based photoelectrodes prepared by two different techniques, namely spray pyrolysis and electrochemical deposition, followed by photoelectrochemical analysis at pH 13 (highly alkaline) and pH 8 (near neutral) in 0.1 M NaOH solution for solar hydrogen generation. The study also investigates the influence of morphology at the semiconductor electrode/electrolyte interface along with quantitative determination of the morphological parameters of the rough electrode surface affecting the photoelectrochemical response using power spectral density analysis. Studies revealed that the Fe 2 O 3 sample (E_100cy) prepared with 100 cycles of electrochemical deposition showed the highest photocurrent density of 2.37 mA cm -2 and 1.18 mA cm -2 at 1 V vs. SCE at pH 13 and 8 respectively. Power spectral density analysis exhibited that E_100cy possesses smallest surface features contributing to the PEC response with a lower cut off length scale of 17.23, upper cut off length scale of 150.45, maximum fractal dimension of 2.62 and maximum average rms roughness of 17.52 nm, offering the maximum surface area for charge transfer reactions at the electrode/electrolyte interface. The sample E_100cy exhibited the highest ABPE of 1.29% and IPCE of 37.5%., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)