Amorphous FeOOH Oxygen Evolution Reaction Catalyst for Photoelectrochemical Water Splitting

Abstract

Reaching the goal of economical photoelectrochemical (PEC) water splitting will likely require the combination of efficient solar absorbers with high activity electrocatalysts for the hydrogen and oxygen evolution reactions (HER and OER). Toward this goal, we synthesized an amorphous FeOOH (a-FeOOH) phase that has not previously been studied as an OER catalyst. The a-FeOOH films show activity comparable to that of another OER cocatalyst, Co-borate (Co-Bi), in 1 M Na2CO3, reaching 10 mA/cm(2) at an overpotential of ∼550 mV for 10 nm thick films. Additionally, the a-FeOOH thin films absorb less than 3% of the solar photons (AM1.5G) with energy greater than 1.9 eV, are homogeneous over large areas, and act as a protective layer separating the solution from the solar absorber. The utility of a-FeOOH in a realistic system is tested by depositing on amorphous Si triple junction solar cells with a photovoltaic efficiency of 6.8%. The resulting a-FeOOH/a-Si devices achieve a total water splitting efficiency of 4.3% at 0 V vs RHE in a three-electrode configuration and show no decrease in efficiency over the course of 4 h.

Urchin-like FeOOH hollow microspheres decorated with MnO2 for enhanced supercapacitor performance

“…The Fe 2p spectrum exhibits two main peaks at 711.1 and 724.8 eV in addition to their shake-up satellite peaks at 719.1 and 732.4 eV (Fig. 3b) [36][37][38]. The O 1s spectrum can be fitted into two peaks, where the lower binding energy peak at 529.9 eV is associated with an Fe-O-Fe bond, whereas the higher peak at 531.4 eV is due to an Fe-O-H bond (Fig.…”

An Operando Investigation of (Ni–Fe–Co–Ce)Ox System as Highly Efficient Electrocatalyst for Oxygen Evolution Reaction

“…[1][2][3] Ascertaining structure-property relationships remains a central challenge in the field of heterogeneous catalysis and comprises an important strategy for the development of superior electrocatalysts. [4][5][6] Enhanced catalytic activity has been 2 ascribed to amorphous materials as heterogeneous catalysts and OER electrocatalysts, [7][8][9][10][11][12][13][14][15][16][17][18] while high activity and stability has also been reported for nanostructured, multi-phase heterogeneous catalysts and electrocatalysts, with the behavior attributed to cooperative effects like spill-over or unique interfacial crystallographic structures. [19][20][21] Among the most active and investigated OER electrocatalysts in basic electrolytes are transition metal oxy hydroxides.…”

Highly Enhanced Electrochemical Water Oxidation Reaction over Hyperfine β-FeOOH(Cl):Ni Nanorod Electrode by Modification with Amorphous Ni(OH)2

“…As examples, Choi et al demon-strated the photo-oxidation of water using BiVO 4 coated with γ-FeOOH, 23,24 while Mullins et al reported the photooxidation of water over SiGe-jn in conjunction with amorphous FeOOH. 25 Mullins also determined that the reaction overpotential could be reduced by doping with Ni (520%). 26 In contrast, there have been few reports regarding the use of crystalline β-FeOOH(Cl) (akaganeite) systems.…”