Study of NiFe2O4/Cu2O p-n heterojunctions for hydrogen production by photocatalytic water splitting with visible light

To date, synthesis of visible light-active materials for photocatalytic water splitting is a promising challenge for future applications, e.g., photocatalytic reactors for hydrogen production with solar energy. Type p-n heterojunctions are an alternative to improve electronic properties of pure phase semiconductors and achieve a higher hydrogen production with photocatalytic water splitting. In this work, heterojunctions of NiFe2O4/Cu2O at mass percentages of 75/25, 50/50 and 25/75, are generated by impregnation method and thermal annealing starting from pristine materials NiFe2O4 and Cu2O synthesized by Pechini's method and Benedict's reaction respectively. A photocatalytic evaluation for hydrogen production was performed by means of gas chromatography for pristine and heterojunctions in order to correlate their textural, structural, chemical and electronic properties with their photocatalytic activity, finding a direct correlation between charge carrier concentration and hydrogen production. Finally, the material that exhibited higher hydrogen production was the 50/50 ratio with a production 120 times greater at 24 h in comparison with pristine photocatalysts.