Shi Le, Xu Ao, Chen Guanhua, Zhao Tianshou
Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong, China.
Department of Chemistry, The University of Hong Kong , Pokfluam Road, Hong Kong, China.
J Phys Chem Lett. 2017 Sep 21;8(18):4354-4361. doi: 10.1021/acs.jpclett.7b01999. Epub 2017 Aug 30.
Recent reports on proton conduction across pristine graphene and hexagonal boron nitride (h-BN) provide a new avenue for the design of proton exchange membranes. The uniform pores formed by the electron clouds of two-dimensional (2D) crystals can effectively block the undesired transportation of other species thus ultrahigh selectivity can be achieved. With the aid of first-principles calculations, we investigate the proton conduction process across six kinds of intact 2D crystals, namely graphene, h-BN, β boron sheet, χ boron sheet, phosphorene, and silicene. To clarify the proton conduction mechanism, three proton penetration modes are proposed: dissociation-penetration, adsorption-penetration, and direct penetration. Based on our calculation results, for graphene and h-BN without atomic defects, they are unlikely to provide sufficient proton conductivity at room temperature when no bias potential is applied. By contrast, the β boron sheet, χ boron sheets, and silicene exhibit relatively lower proton penetration energy barriers, making them prospective candidates for future proton exchange membrane applications.
最近关于质子在原始石墨烯和六方氮化硼（h-BN）中传导的报道为质子交换膜的设计提供了一条新途径。二维（2D）晶体的电子云形成的均匀孔隙可以有效阻止其他物种的不必要传输，从而实现超高的选择性。借助第一性原理计算，我们研究了质子在六种完整的二维晶体中的传导过程，即石墨烯、h-BN、β硼片、χ硼片、磷烯和硅烯。为了阐明质子传导机制，我们提出了三种质子穿透模式：解离穿透、吸附穿透和直接穿透。根据我们的计算结果，对于没有原子缺陷的石墨烯和h-BN，在不施加偏置电位的情况下，它们在室温下不太可能提供足够的质子传导率。相比之下，β硼片、χ硼片和硅烯表现出相对较低的质子穿透能垒，使其成为未来质子交换膜应用的潜在候选材料。
