NiFe-layered double hydroxide decorated BiVO₄ photoanode based bi-functional solar-light driven dual-photoelectrode photocatalytic fuel cell

Photocatalytic fuel cell (PFC) synergizes photocatalytic degradation of organic pollutants and fuel cell electrochemical reaction to take advantage of the chemical energy stored in the compounds. Herein, we report a novel 3D structured NiFe-layered double hydroxide (LDH)/BiVO₄ photoanode and Cu₂O-based photocathode for enhancing the efficiency of PFC for the first time. The photoanode was synthesized via a facile hydrothermal and microwave-assisted hydrothermal approach. The experimental results show that the photocurrent density and light harvesting of the PFC increase significantly. The enhanced performance is attributed to the formation of heterojunction at the photoanode resulting in reduction in the interface charge carrier recombination at the NiFe-LDH/BiVO₄ junction and lower bandgap energy compared with bare BiVO_4. The photocurrent density of the NiFe-LDH/BiVO₄ is 90% higher than that of bare BiVO₄ using Na₂SO₃ as the hole scavenger for substrate and 1 M phosphate buffer solution as the supporting electrolyte. The enhanced BiVO₄ works as an efficient photoanode in PFC. The open-circuit voltage, short-circuit current and actual maximum power density of the NiFe-LDH/BiVO₄-Cu₂O/Cu PFC are 0.647 V, 0.196 mA cm⁻² and 74 µW cm⁻², respectively. The good performance demonstrates that the PFC is a promising technology for wastewater treatment in an eco-friendly, low-cost manner.