Hollow Cuboidal Metal Oxide-Based Asymmetric Electrode Configuration for High-Performance Anion Exchange through Quaternized Pyridine-Poly(vinyl alcohol) @ Metal Hydroxide Nanosheets for Water Dissociation

Abstract

Functionalization plays a pivotal role in enabling the deliberate design of membranes to be tailored as an anion exchange or a cation exchange, thereby yielding improved ion exchange capacity. In this study, we have engineered a bipolar membrane (BPM) by integrating quaternized pyridine-functionalized poly(vinyl alcohol) (PVA) as an anion exchange membrane (AEM), combined with an activated Nafion as the cation exchange membrane (CEM). The ion exchange capacity (IEC) measurements revealed that the synthesized AEM possesses an IEC value of 2.3 mmol/g, a measure equivalent to the values characteristic of the most effective commercially available AEMs. The hybrid BPM fabricated through the incorporation of β-Ni(OH) 2 nanosheets between the AEM and CEM was found to be remarkably enhancing the water dissociation (WD) reaction and exhibiting a substantial 55.7% increase in water uptake capacity. Incorporating a unique asymmetric electrode setup having hollow cuboidal CuO significantly boosted the efficiency, enhancing overall water-splitting and dissociation facilitated by the BPM. Systematic experimentation revealed our system's proficiency, achieving a remarkable 0.90 V at ΔpH ≈ 0 with a current density of 5.52 mA/cm 2 , and 0.91 V at ΔpH ≈ 12 providing 7.40 mA/cm 2 , showcasing reduced voltage requirements for the water dissociation process.