Vanadium Oxide Nanosheet-Infused Functionalized Polysulfone Bipolar Membrane for an Efficient Water Dissociation Reaction

Abstract

A high-performing bipolar membrane (BPM) was fabricated using functionalized polysulfones as the ion-exchange layers (IELs) and two-dimensional (2D) V2O5-nanosheets blended with polyvinyl alcohol (PVA) as the water dissociation catalyst (WDC) at the interfacial layer. The composite BPM showed a low resistance of 0.79 Ω cm2, confirming the good contact between the IEL and WDC, much needed for the ionic conductivity. It also demonstrated high water dissociation performance with a water dissociation voltage of 1.11 V corresponding to a current density of 1.02 mA/cm2 in the presence of a 1 M NaCl electrolytic solution. The functionalization of the polysulfone with −SO3 – and R4N+ groups successfully resulted in the increase of hydrophilicity of the polymer, thereby increasing the water uptake capacity of the membranes. The blending of 2D V2O5 nanosheets with PVA proved to be an effective WDC, as confirmed by the increased conductivity and efficiency of the water dissociation (WD) reaction. The 2D V2O5-ns have great potential toward water adsorption onto its surface, thereby interacting with the water molecules, weakening the bonding force of water, and dissociating it into H+ and OH–. The transportation of coions across the membranes and generation of protons and hydroxyl ions at the interfacial layer are correlated with the change in the pH of the catholyte and anolyte as a function of current density during the WD reaction. The high performance of the composite BPM (BPM_VO-ns) was demonstrated at a higher current density of 100 mA/cm2 with a WD resistance of 0.027 Ω cm2. The durability was tested by subjecting it to 45 h of run at lower (1.02 mA/cm2) and higher (100 mA/cm2) current densities which display a negligible change in the interlayer voltage. Thus, the fabricated composite BPMs pave the way to be utilized for efficient and durable WD reactions under neutral electrolytic conditions.

Bipolar Membrane Seawater Splitting for Hydrogen Production: A Review

“…Such exceptional stability can be attributed to PAEK’s inherent properties, specifically the rigid aromatic ring present in its chemical structure, which contributes to its high resistance to chemical degradation. Numerous works have exerted substantial endeavors to amplify the rate of water dissociation in BPM electrolyzers. − Nevertheless, the utilization of the BPM electrolyzer in seawater electrolysis is relatively limited. The efficacy of BPM electrolyzers in seawater electrolysis is discussed further in the next section.…”

“…Numerous works have exerted substantial endeavors to amplify the rate of water dissociation in BPM electrolyzers. 168 − 171 Nevertheless, the utilization of the BPM electrolyzer in seawater electrolysis is relatively limited. The efficacy of BPM electrolyzers in seawater electrolysis is discussed further in the next section.…”

Recent Development and Challenges of Bipolar Membranes for High Performance Water Electrolysis

“…After conducting an optimization of the structure of the bipolar membrane water electrolysis cell, it was discovered that utilizing TiO 2 with a particle size of 30 nm as the WD catalyst can deliver the best performance with the cell voltage lower than 2 V at a high current density of 500 mA cm –2 . Referring to this thought, Bhowwick and Qureshi recently used 2D V 2 O 5 nanosheets blended with PVA as IL catalysts, resulting in a WD voltage of 1.11 V in 1 M NaCl electrolyte solution, with a low WD resistance of only 0.027 Ω cm 2 at a high current density of 100 mA cm –2 . Despite significant advancements in research, it is crucial to emphasize the fact that the stability of BPM-based water electrolyzers remains a concern.…”

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

“…Central to this interaction is the presence of surface-exposed –OH groups, which can readily engage in hydrogen bonding with water molecules . Theoretical studies have revealed that while the dissociation of an isolated water molecule encounters kinetic hindrances, the dissociation of a water molecule forming an interaction with the lattice hydrogen or oxygen of another crystal lattice, particularly from hydroxide or oxide, occurs more readily. − This enhanced dissociation process promotes the WD mechanism. In comparison to bulk materials and alternative nanostructured counterparts, the superiority of two-dimensional (2D) β–Ni­(OH) 2 nanosheets as a WDC is evident due to their elevated specific surface area and the availability of exposed active sites, which are conducive to enhancing the water adsorption.…”