Singh Soni, Taketsugu Tetsuya, Singh Raman K
University Department of Chemistry, Jai Prakash University, Chapra 841301, Bihar, India.
Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
ACS Omega. 2021 Nov 19;6(48):32739-32748. doi: 10.1021/acsomega.1c04484. eCollection 2021 Dec 7.
We used long-range-corrected density functional theory to investigate the hydration, p values, and harmonic vibrational spectroscopy of sulfonated polybenzophenone (SPK) block-copolymer hydrocarbon membranes to ascertain the reasons why this gives comparable or higher proton conductivities against Nafion over a wide range of humidity. It was found that a minimum of three water molecules are required for proton dissociation in both membranes. From natural population analysis, it was noticed that the proton dissociation of SPK membranes is nearly comparable to Nafion at relatively low water content. Next, we explored the applicability of the appropriate treatment for p and proton's energy with a benchmark set (AKB) scheme to compute the p values for these membranes. These results indicate that the proton dissociative abilities of sulfonic acid groups of the SPK membrane are higher than those of Nafion. This could be one of the reasons for the SPK membrane to show higher proton conductivities at high relative humidity. Furthermore, the effect of hydration on the proton conductivity of membranes illustrates that asymmetric stretching of the SO mode was in agreement with Nafion ones but opposite trends were found in the case of symmetric stretching of the SO mode upon hydration.
我们使用长程校正密度泛函理论来研究磺化聚二苯甲酮（SPK）嵌段共聚物碳氢化合物膜的水合作用、p值和谐波振动光谱，以确定在广泛的湿度范围内，该膜相对于Nafion具有相当或更高质子传导率的原因。研究发现，两种膜中质子解离都至少需要三个水分子。通过自然布居分析发现，在相对较低的含水量下，SPK膜的质子解离与Nafion几乎相当。接下来，我们用基准集（AKB）方案探索了对p值和质子能量进行适当处理的适用性，以计算这些膜的p值。这些结果表明，SPK膜磺酸基团的质子解离能力高于Nafion。这可能是SPK膜在高相对湿度下显示出更高质子传导率的原因之一。此外，水合作用对膜质子传导率的影响表明，SO模式的不对称拉伸与Nafion的情况一致，但在水合作用下SO模式的对称拉伸情况则呈现相反趋势。
