Photoelectrochemical Properties of LaFeO₃ Nanoparticles

Abstract

The photoelectrochemical properties of LaFeO3 nanoparticles are discussed for the first time. Highly phase‐pure LaFeO3 particles prepared by a novel ionic‐liquid‐based method are characterized by a (60±14) nm mean size and a band gap of (2.56±0.07) eV. Thin films deposited by screen printing exhibit photocurrent responses associated with hydrogen generation at potential up to 1 V more positive than the formal hydrogen potential. Analysis of the photocurrent responses as a function of photon flux and potential bias suggest that the hole‐collection efficiency at the back contact is in competition with interfacial water oxidation.

Metal Doping to Enhance the Photoelectrochemical Behavior of LaFeO3 Photocathodes

“…Such a band‐gap value is in line with other reported values . A direct transition band‐gap value of 2.7 eV can also be calculated (Figure C), which is slightly higher than other reported values (2.47–2.56 eV) for the direct transition of LaFeO 3 nanoparticles, and closer to the 2.65 eV value obtained for 25–55 nm thick films . Notably, the indirect and direct band gaps change slightly with the doping level.…”

“…Many metal oxides, which include those with a complex stoichiometry (i.e., ternary and quaternary oxides), behave as semiconductors and present a good stability in aqueous environments, which makes them attractive candidates for water splitting devices. Among ternary oxides, p‐type behavior has been uncovered for some perovskites, spinels, delafossites, and scheelites . Perovskite‐type oxides may be a good alternative because most of them exhibit a p‐type semiconductor nature and high stability under illumination in aqueous solutions.…”

“…Perovskite‐type oxides may be a good alternative because most of them exhibit a p‐type semiconductor nature and high stability under illumination in aqueous solutions. For instance, LaFeO 3 is a promising candidate, and several studies in which this material is investigated in the context of photoelectrochemistry have been reported recently . Celorrio et al .…”

“…For instance, LaFeO 3 is a promising candidate, and several studies in which this material is investigated in the context of photoelectrochemistry have been reported recently . Celorrio et al . studied the properties of a nanostructured LaFeO 3 electrode as a photocathode, and subsequently, Yu and co‐workers prepared compact LaFeO 3 electrodes by using pulsed laser deposition (PLD) and a p‐LaFeO 3 /n‐Fe 2 O 3 water‐splitting photocell stable even after 120 h .…”

Study of Copper Ferrite as a Novel Photocathode for Water Reduction: Improving Its Photoactivity by Electrochemical Pretreatment

“…Non-oxide materials, such as Si, [6][7][8][9] SiC, [10][11][12] and InP, [13,14] are among the most extensively studied. [23][24][25][26] Spinel ferrites are compounds with the general formula MFe 2 O 4 ,i nw hich Mi sametal.T hey are good candidates as PEC materials owing to their relatively narrowb and gap, which enables them to absorbv isible light, and the fact that they can exhibit p-type behavior.I nf act, their photocatalytic ability for H 2 productionh as already been studied. [15][16][17][18][19][20][21] It has ad irect band gap of 2eV, with af avorable CB edge position for hydrogene volution.…”