Bhowmick Sourav, Qureshi Mohammad
Department of Chemistry, Indian Institute of Technology, Guwahati, Assam781039, India.
ACS Appl Mater Interfaces. 2023 Feb 1;15(4):5466-5477. doi: 10.1021/acsami.2c20090. Epub 2023 Jan 23.
A high-performing bipolar membrane (BPM) was fabricated using functionalized polysulfones as the ion-exchange layers (IELs) and two-dimensional (2D) VO-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 cm, 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/cm in the presence of a 1 M NaCl electrolytic solution. The functionalization of the polysulfone with -SO and RN groups successfully resulted in the increase of hydrophilicity of the polymer, thereby increasing the water uptake capacity of the membranes. The blending of 2D VO 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 VO-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/cm with a WD resistance of 0.027 Ω cm. The durability was tested by subjecting it to 45 h of run at lower (1.02 mA/cm) and higher (100 mA/cm) 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.
采用功能化聚砜作为离子交换层（IEL），并将二维（2D）VO纳米片与聚乙烯醇（PVA）混合作为界面层的水解离催化剂（WDC），制备了一种高性能双极膜（BPM）。复合双极膜显示出0.79Ω·cm的低电阻，证实了IEL和WDC之间良好的接触，这是离子传导性所急需的。在1M NaCl电解液存在下，它还表现出高水解离性能，水解离电压为1.11V，对应电流密度为1.02mA/cm²。用-SO₃和RN基团对聚砜进行功能化成功地提高了聚合物的亲水性，从而增加了膜的吸水能力。二维VO纳米片与PVA的混合被证明是一种有效的WDC，水解离（WD）反应的电导率和效率的提高证实了这一点。二维VO纳米片具有很强的表面吸水潜力，从而与水分子相互作用，削弱水的键合力，并将其分解为H⁺和OH⁻。在WD反应过程中，共离子跨膜传输以及界面层质子和氢氧根离子的产生与阴极电解液和阳极电解液pH值随电流密度的变化相关。复合双极膜（BPM_VO-ns）在100mA/cm²的较高电流密度下表现出高性能，WD电阻为0.027Ω·cm。通过在较低（1.02mA/cm²）和较高（100mA/cm²）电流密度下运行45小时来测试其耐久性，结果显示层间电压变化可忽略不计。因此，制备的复合双极膜为在中性电解条件下高效、持久的WD反应开辟了道路。
