A highly ordered honeycomb-like nickel(III/II) oxide-enhanced photocatalytic fuel cell for effective degradation of bisphenol A

Highlights: • Highly interpenetrated honeycomb-like H-NiO_x is prepared by AO-ED methods. • Redox-active H-NiO_x exhibits smaller charge transfer resistance than C-NiO_x. • The H-NiO_x cathode promotes BPA degradation in photocatalytic fuel cells. • The presence of NaClO catholyte can sustain the integrity and stability of H-NiO_x. • Degradation of BPA in photocatalytic fuel cell obeys first-order reaction kinetics. - Abstract: The honeycomb-like nickel(III/II) oxide interpenetrated framework arrays labelled as H-NiO_x are used as cathode catalysts for the degradation of bisphenol A (BPA) in visible light-excited fuel cells. The nanoparticle close-packed NiO_x aggregates (C-NiO_x) and H-NiO_x are prepared by conventional electrodeposition (ED) and advanced oxidation-associated electrodeposition (AO-ED) strategies, carried out by multiple voltammetry controlled in the potential ranges of 0 to –1.3 V and 1.3 to –1.3 V (vs. SCE), respectively. Compared with C-NiO_x, the H-NiO_x frameworks with smaller charge transfer resistance and higher surface-confined redox-active centers exhibit larger cathode electrocatalytic activity for the photocatalytic degradation of BPA. The NaClO can act as a sacrificial agent to sustain the integrity and stability of H-NiO_x cathode. The H-NiO_x-assisted BPA degradation conditions are optimized by changing process variables. The BPA is degraded by 48.5% within 120 min in photocatalytic BPA (1.0 mmol L⁻¹, pH 13) fuel cell employing H-NiO_x cathode, CdS/TiO₂ photoanode and 0.2 mol L⁻¹ NaClO catholyte, and its degradation rate conforms to the first-order reaction kinetic model. The H-NiO_x can remarkably enhance the performances of the photocatalytic fuel cell, achieving a 4.1-fold or 15.2-fold increase in the short circuit current and maximum power density compared with that using bare cathode.