Influence of FeVO4 crystallinity on oxygen evolution reaction activity.

Enhanced oxygen evolution reaction (OER) kinetics plays an important role in the large-scale production of hydrogen via water electrolysis. In this regard, the crystallinity of FeVO 4 is tuned from amorphous to semicrystalline and fully crystalline via precipitation followed by controlled thermal treatment. The prepared FeVO 4 samples show a uniform distribution of spherical nanoparticles (40–60 nm). The tailored amorphous, semicrystalline, and fully crystalline FeVO 4 samples are immobilized on nickel foam and their OER performance was studied. The OER performance of amorphous, semicrystalline, and fully crystalline FeVO 4 shows in the order of amorphous FeVO 4 > semicrystalline FeVO 4 > fully crystalline FeVO 4. The amorphous FeVO 4 demonstrates magnificent enhanced OER kinetics with a small overpotential and high current density compared to the semicrystalline and fully crystalline FeVO 4. The amorphous FeVO 4 exhibits an overpotential of 310 mV at a high current density of 1000 mA cm−2 and also exhibits exemplary stability over 95 h, while semicrystalline FeVO 4 and fully crystalline FeVO 4 respectively require 360 mV and 390 mV to drive a relatively lower current density of 500 mA cm−2. [ABSTRACT FROM AUTHOR]