Direct and scalable dual-laser writing of 3D graphene–MoS2 architectures for high-efficiency pH-universal hydrogen electrocatalysis

Abstract

The rational design of bifunctional electrocatalysts capable of operating efficiently under both acidic and alkaline conditions remains a critical challenge for hydrogen evolution reaction (HER) technologies. Herein, we report a novel, rapid, and scalable dual-laser approach for the in-situ synthesis of MoS2 nanostructures embedded within three-dimensional (3D) laser-induced graphene (LIG) frameworks for efficient HER electrocatalysis. Leveraging the complementary and synergistic capabilities of CO2 (10.6 μm) and blue near-UV (450 nm) lasers, this method enables maskless, binder-free, and chemical-free fabrication of LIG/MoS2 hybrid electrocatalysts under ambient conditions. The CO2 laser induces rapid graphitization of polyimide sheets into a highly 3D porous and conductive graphene-like structure. The UV laser facilitates localized and gentle energy-efficient crystallization of MoS2 catalyst from Mo/S precursors, yielding a uniform, well-integrated, and cross-linked 3D nanoarray architecture. Structural, morphological, and electrochemical characterizations confirmed the synergistic effect of the dual-laser process. The optimal hybrid catalysts LIGUV–MoS2UV and LIGCO2–MoS2UV, exhibited outstanding HER electrocatalytic activity, achieving low overpotentials of 242 and 233 mV in 1 M KOH and 0.5 M H2SO4, respectively, at 10 mA cm2, along with excellent durability and reaction kinetics. This study introduces a novel, sustainable and industry-compatible platform for designing advanced multifunctional HER catalysts, advancing clean energy applications.