Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
Korean National Research Foundation Shinjin Scientist Program, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
Sci Adv. 2017 Mar 31;3(3):e1602215. doi: 10.1126/sciadv.1602215. eCollection 2017 Mar.
We describe the spontaneous formation of composite chalcogenide materials that consist of two-dimensional (2D) materials dispersed in bulk and their unusual charge transport properties for application in hydrogen evolution reactions (HERs). When MoS as a representative 2D material is deposited on transition metals (such as Cu) in a controlled manner, the sulfidation reactions also occur with the metal. This process results in remarkably unique structures, that is, bulk layered heterojunctions (BLHJs) of Cu-Mo-S that contain MoS flakes inside, which are uniformly dispersed in the CuS matrix. The resulting structures were expected to induce asymmetric charge transfer via layered frameworks and tested as electrocatalysts for HERs. Upon suitable thermal treatments, the BLHJ surfaces exhibited the efficient HER performance of approximately 10 mA/cm at a potential of -0.1 V versus a reversible hydrogen electrode. The Tafel slope was approximately 30 to 40 mV per decade. The present strategy was further generalized by demonstrating the formation of BLHJs on other transition metals, such as Ni. The resulting BLHJs of Ni-Mo-S also showed the remarkable HER performance and the stable operation over 10 days without using Pt counter electrodes by eliminating any possible issues on the Pt contamination.
我们描述了复合硫属化物材料的自发形成，这些材料由二维（2D）材料分散在体相内组成，具有不寻常的电荷输运性质，可应用于析氢反应（HER）。当 MoS 作为代表性 2D 材料以受控方式沉积在过渡金属（如 Cu）上时，硫化反应也会与金属一起发生。这一过程产生了非常独特的结构，即含有 MoS 薄片的 Cu-Mo-S 体层异质结（BLHJ），其均匀分散在 CuS 基体中。预期这些结构通过层状框架诱导不对称电荷转移，并作为析氢反应的电催化剂进行测试。经过适当的热处理，BLHJ 表面在相对于可逆氢电极的-0.1 V 电位下表现出约 10 mA/cm 的高效 HER 性能。塔菲尔斜率约为每 decade 30 至 40 mV。通过证明在其他过渡金属（如 Ni）上形成 BLHJ，进一步推广了这一策略。Ni-Mo-S 形成的 BLHJ 也表现出显著的 HER 性能，在不使用 Pt 对电极的情况下可稳定运行超过 10 天，消除了任何可能因 Pt 污染而产生的问题。
