1：Experimental Design and Method Selection:

First-principles calculations based on density functional theory (DFT) were used to optimize geometries and calculate electronic and magnetic properties. The projector-augmented-wave (PAW) method with GGA-PBE exchange-correlation functional was employed in VASP for geometry optimizations, and the Atomistix ToolKit (ATK) based on non-equilibrium Green's function method combined with DFT was used for electronic and magnetic property calculations. Spin-polarized calculations were performed.

2：Sample Selection and Data Sources:

Twelve patterns of zigzag MoSe2 nanoribbon edge structures were considered, including symmetric and asymmetric configurations with different terminations (Mo, Se, or mixed) and hydrogenation states. The nanoribbons were modeled with specific widths (N=12 or 13).

3：3). List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Computational software packages: Vienna ab initio simulation package (VASP) and Atomistix ToolKit (ATK). No physical equipment or materials were used as it is a theoretical study.

4：Experimental Procedures and Operational Workflow:

Geometry optimizations were performed with a cutoff energy of 400 eV, k-point mesh of 5x1x1, convergence tolerance for energy of 10^-5 eV/atom, and force less than 0.01 eV/?. Electronic and magnetic calculations used a cutoff energy of 600 Ry, k-point meshes of 10x1x1 for properties, 25x1x1 for density of states, and 50x1x1 for band structures. A vacuum layer of >20 ? was used to avoid interactions. Results were confirmed by doubling the primitive unit cell.

5：01 eV/?. Electronic and magnetic calculations used a cutoff energy of 600 Ry, k-point meshes of 10x1x1 for properties, 25x1x1 for density of states, and 50x1x1 for band structures. A vacuum layer of >20 ? was used to avoid interactions. Results were confirmed by doubling the primitive unit cell. Data Analysis Methods:

5. Data Analysis Methods: Binding energies were calculated to assess stability. Electronic properties were analyzed through band structures and density of states. Magnetic properties were evaluated via magnetic moments and spin density distributions.