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Aligned Heterointerface‐Induced 1T‐MoS 2 Monolayer with Near‐Ideal Gibbs Free for Stable Hydrogen Evolution Reaction
Author(s) -
Zhang Kan,
Jin Bingjun,
Gao Yujie,
Zhang Shengli,
Shin Hyunjung,
Zeng Haibo,
Park Jong Hyeok
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201804903
Subject(s) - monolayer , molybdenum disulfide , tafel equation , gibbs free energy , materials science , graphene , stacking , phase (matter) , electrolyte , chemical physics , electrochemistry , nanotechnology , chemistry , thermodynamics , electrode , organic chemistry , physics , metallurgy
1T‐phase molybdenum disulfide (1T‐MoS 2 ) exhibits superior hydrogen evolution reaction (HER) over 2H‐phase MoS 2 (2H‐MoS 2 ). However, its thermodynamic instability is the main drawback impeding its practical application. In this work, a stable 1T‐MoS 2 monolayer formed at edge‐aligned 2H‐MoS 2 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 2 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 −1 and 10 h stability in acidic electrolyte. The unexpected activity of EA‐2H/1T/RGO beyond 1T‐MoS 2 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 H* ) to decrease from 0.13 to 0.07 eV, which is closest to the ideal value (0.06 eV) of 2H‐MoS 2 . 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.