Zhang Kan, Jin Bingjun, Gao Yujie, Zhang Shengli, Shin Hyunjung, Zeng Haibo, Park Jong Hyeok
Key Laboratory of Advanced Display Materials and Devices, Ministry of Industry and Information Technology, Institute of Optoelectronics & Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China.
Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea.
Small. 2019 Feb;15(8):e1804903. doi: 10.1002/smll.201804903. Epub 2019 Jan 30.
1T-phase molybdenum disulfide (1T-MoS ) exhibits superior hydrogen evolution reaction (HER) over 2H-phase MoS (2H-MoS ). However, its thermodynamic instability is the main drawback impeding its practical application. In this work, a stable 1T-MoS monolayer formed at edge-aligned 2H-MoS and a reduced graphene oxide heterointerface (EA-2H/1T/RGO) using a precursor-in-solvent synthesis strategy are reported. Theoretical prediction indicates that the edge-aligned layer stacking can induce heterointerfacial charge transfer, which results in a phase transition of the interfacial monolayer from 2H to 1T that realizes thermodynamic stability based on the adhesion energy between MoS and graphene. As an electrocatalyst for HER, EA-2H/1T/RGO displays an onset potential of -103 mV versus RHE, a Tafel slope of 46 mV dec and 10 h stability in acidic electrolyte. The unexpected activity of EA-2H/1T/RGO beyond 1T-MoS is due to an inherent defect caused by the gliding of S atoms during the phase transition from 2H to 1T, leading the Gibbs free energy of hydrogen adsorption (ΔG ) to decrease from 0.13 to 0.07 eV, which is closest to the ideal value (0.06 eV) of 2H-MoS . The presented work provides fundamental insights into the impressive electrochemical properties of HER and opens new avenues for phase transitions at 2D/2D hybrid interfaces.
1T相二硫化钼（1T-MoS₂）在析氢反应（HER）方面比2H相二硫化钼（2H-MoS₂）表现更优。然而，其热力学不稳定性是阻碍其实际应用的主要缺点。在这项工作中，报道了一种使用溶剂前驱体合成策略在边缘对齐的2H-MoS₂和还原氧化石墨烯异质界面（EA-2H/1T/RGO）上形成的稳定1T-MoS₂单层。理论预测表明，边缘对齐的层堆叠可诱导异质界面电荷转移，这导致界面单层从2H相转变为1T相，基于MoS₂与石墨烯之间的粘附能实现热力学稳定性。作为HER的电催化剂，EA-2H/1T/RGO相对于可逆氢电极（RHE）的起始电位为 -103 mV，塔菲尔斜率为46 mV dec⁻¹，在酸性电解质中具有10小时的稳定性。EA-2H/1T/RGO超出1T-MoS₂的意外活性归因于从2H相转变为1T相过程中S原子滑动引起的固有缺陷，导致氢吸附吉布斯自由能（ΔG）从0.13 eV降至0.07 eV，这最接近2H-MoS₂的理想值（0.06 eV）。这项工作为HER令人印象深刻的电化学性质提供了基本见解，并为二维/二维混合界面的相变开辟了新途径。
