Evaluating spinel ferrites MFe₂O₄ (M = Cu, Mg, Zn) as photoanodes for solar water oxidation: prospects and limitations

Abstract

The search for ideal semiconductors for photoelectrochemical solar fuel conversion has recently recognized the spinel ferrites as promising candidates due to their optoelectronic tunability together with superb chemical stability.

Spinel Structural Disorder Influences Solar‐Water‐Splitting Performance of ZnFe2O4 Nanorod Photoanodes

“…Nanorod-array ZFO photoanodes were prepared using a modified conversion route [12] via β-FeOOH on F-doped tin oxide (FTO) coated glass substrates (full experimental details described in the Supporting Information). The synthesis was performed at 500, 600, 700 or 800 °C (for 20 min, which was sufficient to form the spinel and avoided adversely affecting the electrical resistivity of the FTO substrate, see Table S1, Supporting Information) and a final annealing at 200 °C under H 2 was added to increase the n-type character.…”

“…It should be noted that the value of d assumes an isotropic domain shape, which is an approximation in the case of our nanorod-shaped features, however, the trend of increasing domain size with temperature is expected. [12] Typical results for photoanodes prepared at the different synthesis temperatures are shown in Figure 3a. [25][26][27][28] Since the spinel crystal structure is composed of a cubic closedpacked array of oxygen atoms with the tetrahedral and octahedral cavities occupied by divalent or trivalent cations, the structural formula of zinc ferrite can be written as www.advmat.de www.advancedsciencenews.com T sites occupied by Fe 3+ ).…”

“…[10] The spinel ferrites (MFe 2 O 4 , M = Zn, Mg, Cu, Ca, etc.) [11,12] Specifically, n-type ZFO has garnered considerable interest as a secondary overlayer component of various composite photoelectrode systems such as TiO 2 /ZFO, [13,14] Fe 2 O 3 /ZFO, [15,16] and ZnO/ZFO, [17] to enhance photogenerated charge extraction in the primary oxide. [11,12] Specifically, n-type ZFO has garnered considerable interest as a secondary overlayer component of various composite photoelectrode systems such as TiO 2 /ZFO, [13,14] Fe 2 O 3 /ZFO, [15,16] and ZnO/ZFO, [17] to enhance photogenerated charge extraction in the primary oxide.…”

“…However, given the vast number of possible ternary and multinary metal oxides, interest in developing an ideal material remains. [11,12] Specifically, n-type ZFO has garnered considerable interest as a secondary overlayer component of various composite photoelectrode systems such as TiO 2 /ZFO, [13,14] Fe 2 O 3 /ZFO, [15,16] and ZnO/ZFO, [17] to enhance photogenerated charge extraction in the primary oxide. represent an attractive class of ternary metal oxides as photoelectrodes for PEC solar water splitting [4,10] given their suitable light harvesting in the visible range (bandgap energy, E g = 1.4-2.1 eV), abundant constituent elements, and demonstrated long-term photostability.…”

Double‐Pulse Electrodeposition of CuGaS2 Photovoltaic Thin Film

“…Its bandgap is close to the optimum for the fabrication of intermediate band thin film solar cells, theoretically able to reach value of energy conversion efficiency of ∼63 %, significantly higher than the theoretical value for a single band‐gap solar cell (∼41 %) . CGS films has been deposited by several reported approaches: vacuum‐based techniques, spray pyrolysis, nanocrystalline ink‐based deposition, electrodeposition, etc. Among these mentioned deposition techniques, electrodeposition offers low‐cost equipment, efficient material utilization and scalability for large scale production .…”