Graphdiyne oxide-sandwiched MoS2 heterostructure with sufficient hetero-interphase and highly expanded interlayer for efficient hydrogen evolution

Molybdenum disulfide (MoS2) has emerged as an attractive and cost-effective alternative to platinum (Pt) catalysts in electrochemical hydrogen evolution reactions (HER). However, its limited conductivity and active sites pose a challenge to its electrocatalytic performance. To address this issue, a well-defined layer-by-layer MoS2/graphdiyne oxide (GDYO) heterostructure (MGDYO) is fabricated via electrostatic self-assembly. GDYO nanosheets are inserted between the layers of MoS2, expanding the interlayer spacing of adjacent MoS2 nanosheets and exposing more active sites. The experimental and theoretical results consistently demonstrate that incorporating GDYO leads to a reconstruction of the surface state, which increases electrical conductivity and lowers Gibbs free energy. The layer-by-layer heterostructure allows for the simultaneous modification of the structural and electrical properties of MoS2, resulting in a synergistic effect. The MGDYO electrocatalyst exhibited a reduced overpotential of 237 mV (10 mA cm−2), a lower Tafel slope of 53.04 mV dec−1 than individual building blocks, and favorable stability. Overall, the facile method and innovative design concept for the fabrication of MGDYO with exceptional HER performance presented in this study could pave the way for other MoS2-based energy material designs.