Nano-ferrites for water splitting: unprecedented high photocatalytic hydrogen production under visible light

Abstract

In the present investigation, hydrogen production via water splitting by nano-ferrites was studied using ethanol as the sacrificial donor and Pt as co-catalyst. Nano-ferrite is emerging as a promising photocatalyst with a hydrogen evolution rate of 8.275 μmol h⁻¹ and a hydrogen yield of 8275 μmol h⁻¹ g⁻¹ under visible light compared to 0.0046 μmol h⁻¹ for commercial iron oxide (tested under similar experimental conditions). Nano-ferrites were tested in three different photoreactor configurations. The rate of hydrogen evolution by nano-ferrite was significantly influenced by the photoreactor configuration. Altering the reactor configuration led to sevenfold (59.55 μmol h⁻¹) increase in the hydrogen evolution rate. Nano-ferrites have shown remarkable stability in hydrogen production up to 30 h and the cumulative hydrogen evolution rate was observed to be 98.79 μmol h⁻¹. The hydrogen yield was seen to be influenced by several factors like photocatalyst dose, illumination intensity, irradiation time, sacrificial donor and presence of co-catalyst. These were then investigated in detail. It was evident from the experimental data that nano-ferrites under optimized reaction conditions and photoreactor configuration could lead to remarkable hydrogen evolution activity under visible light. Temperature had a significant role in enhancing the hydrogen yield.