A subtle functional design of hollow CoP@MoS2 hetero-nanoframes with excellent hydrogen evolution performance

Abstract

As the star material among nonprecious electrocatalysts, molybdenum disulfide (MoS2) has received much attention. However, the catalytic inertness of the basal plane, low conductivity of its steady state (2H phase), and the agglomeration of lamellar structures have seriously hindered its catalytic performance. It is very essential to design and modulate the morphology and phase of MoS2 to improve the above issues by synergistic regulation of electrical structure and defect engineering. Herein, MoS2 was delicately composited on CoP nanoframe derived from a typical metal–organic frame nanostructure (ZIF-67), forming the hollow CoP@MoS2 hetero-nanoframe. This exquisite externally layered and internally hollow CoP@MoS2 electrocatalyst demonstrated excellent catalytic performance for the hydrogen evolution reaction, with a low overpotential of 119 mV at 10 mA cm−2, a small Tafel slope of 49 mV dec−1, a large electric double-layer capacitance of 10.28 mF cm−2, and prominent long-term stability. The remarkable catalytic performance of hollow CoP@MoS2 hetero-nanoframe can be attributed to the unique architecture of the hetero-nanostructures, appropriate component ratios, strong interaction between CoP and MoS2, and large-scale defects and disorder. First-principles density-functional theory calculations can prove the above arguments adequately, the hydrogen adsorption free energy of CoP@MoS2 is close to zero.