One-step ultrafast laser induced synthesis of strongly coupled 1T-2H MoS2/N-rGO quantum-dot heterostructures for enhanced hydrogen evolution

This work offers a novel, one-step, and controllable strategy using spatially shaped laser for preparation strongly coupled 1T-2H MoS 2 /N-rGO quantum-dot heterostructures with unique structural feature and exceptional catalytic performance. The introduction of both phase transition and GQDs into MoS 2 QDs simultaneously improve the number of accessible active sites and conductivity, thus obtaining excellent catalytic performance. • This method innovates the traditional processing methods of quantum-dot heterostructures. • The construction of vertical heterostructures of MoS 2 /rGO and in-plane heterojunction of 1T-2H MoS 2 . • The sulfur vacancy promotes the phase transformation from 2H- to 1 T-MoS 2 . • The 0D/0D heterostructures exhibits improved electrocatalytic HER activity. • The enhanced catalysis activity is attributed to the interfacial electronic structure modulation. Strongly coupled transition-metal dichalcogenides/carbon hybrids are cost-effective and robust electrocatalysts for hydrogen evolution reaction, and further designing quantum-dot structures of hybrid catalysts often maximizes the accessible active sites and facilitates charge transfer and consequently their catalytic performance. However, the rational design and facile synthesis of such quantum-dot hybrid still remains a central challenge. Herein, an effective and controllable strategy is presented for one-step synthesis of strongly coupled 1T-2H MoS 2 /N-rGO quantum-dot heterostructures using spatially shaped laser ablation in liquid (LAL). The yield of QDs reaches 75.16 wt%, indicating that the mass production of such QDs is feasible using LAL method. Moreover, both characterizations and density functional theory calculations reveal that the much enhanced electrochemical HER performance arises from the optimized chemical composition, improved conductivity, and strongly coupled structural/electronic features. Correspondingly, the as-formed quantum-dot heterostructures exhibit remarkably low overpotential of 97 mV at 10 mA c 2 , a small Tafel slope of 39 mV dec -1 and high durability, outperformed most previously reported QDs-based electrocatalysts. This versatile strategy overcomes the current limitations of strong-coupled quantum-dot heterostructures materials preparing and offers a synergistic modulation approach for designing highly active HER catalysts viable for practical application.