PrFeO₃ Photocathodes Prepared Through Spray Pyrolysis

Perovskite oxides are receiving wide interest for photocatalytic and photoelectrochemical devices, owing to their suitable band gaps for solar light absorption and stability in aqueous applications. Herein, we assess the activity of PrFeO₃ photocathodes prepared by using spray pyrolysis and calcination temperatures between 500 and 700 °C. Scanning electron microscopy shows corrugated films of high surface coverage on the conductive glass substrate. The electrochemically active surface area shows slight decreases with temperature increases from 500 to 600 and 700 °C. However, transient photocurrent responses and impedance spectroscopy data showed that films calcined at higher temperatures reduced the probabilities of recombination due to trap states, resulting in faster rates of charge extraction. In this trade-off, a calcination temperature of 600 °C provided a maximum photocurrent of -130±4 μA cm⁻² at +0.43 V_RHE under simulated sunlight, with an incident photon-to-current conversion efficiency of 6.6 % at +0.61 V_RHE and 350 nm and an onset potential of +1.4 V_RHE for cathodic photocurrent.