Synergistic enhancement of photocatalytic efficiency and durability in CoNi-decorated Cu2O/Cu films for superior synthetic dye degradation

The Cu₂O/Cu emerges as a promising candidate for photocatalytic application owing to its efficient photon absorption in the visible light spectrum. However, the susceptibility of Cu₂O-based photocatalysts to self-decomposition diminishes their effectiveness. This study introduces CoNi as co-catalyst to enhance the durability of Cu₂O/Cu photocatalyst. Electrodeposition was employed to decorate the Cu₂O/Cu crystal surface with Co, Ni and CoNi. The deposition potential of CoNi was optimized to produce a high-performance photocatalyst. The utilization of CoNi co-catalyst resulted in significant enhancements in photoelectrochemical properties under light irradiation when compared to using a single Co or Ni co-catalyst, suggesting a synergistic effect between Co and Ni within the system. The enhancement is evidenced by a noteworthy increase in the photocurrent of the photocatalyst, rising from 10.24 mA/cm² to 20.81 mA/cm². In addition, the decoration of CoNi resulted in a reduction of the charge transfer resistance from 4.2 kΩ to 0.7 kΩ, while simultaneously increasing the electrochemically active surface area of the photocatalyst from 15.49 cm² to 157.69 cm². The observed modifications lead to a substantial improvement in the photocatalytic efficiency, resulting in an impressive 88 % degradation of methylene blue, which is 3.4 times higher than achieved in the absence of the co-catalyst. Moreover, there was a significant improvement in the photostability of the photocatalyst, with an increase from 16.81 % to 50.55 %. These findings demonstrate the significance of CoNi co-catalyst decoration in producing a highly active and durable photocatalyst, making it a promising candidate for efficient synthetic dyes degradation.