Hydrothermally synthesized Iron Phosphate Hydroxide thin film electrocatalyst for electrochemical water splitting

Hydrogen production is an immediate need to replace the fossil fuels to keep environmental balance, and water splitting is an effective solution in presence of catalyst through oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, for the first time, we have synthesized Iron Phosphate Hydroxide (Fe 2.95 (PO 4 ) 2 (OH) 2 ) thin film electrode as a superior electrocatalyst by facile hydrothermal method using binder free approach. The crystallographic properties are studied from X-ray diffraction pattern, and Reitveld refinement analysis shows best fit with the tetragonal Lipscombite structure of Iron Phosphate Hydroxide (Fe 2.95 (PO 4 ) 2 (OH) 2 ). Flower like structure consist of agglomerated nanorods on micro and sub-micrometric spheres of Fe 2.95 (PO 4 ) 2 (OH) 2 exhibits lower overpotential of 281 mV at 10 mA/cm 2 current density towards OER in alkaline (1 M KOH) medium and maintains its activity after 12 h catalytic stability test. Moreover, prepared electrode shows HER with overpotential 165.7 mV at current density 10 mA/cm 2 in acidic (1 M H 3 PO 4 ) medium and demonstrates enhanced performance (126.4 mV overpotential) after 12 h catalytic stability. The Fe 2.95 (PO 4 ) 2 (OH) 2 thin film electrodes show superior performance in OER and HER, compared with its oxide counterpart (Fe 2 O 3 ).