A periodic ordered porous nickel structure (unit size 0.5 mm, porosity 50%) was fabricated from pure nickel powder (5-20 µm, spherical) by selective laser melting (200 W, 500 mm/s, 0.01 mm layer thickness, 0.08 mm scanning interval) in argon, yielding a 20×20×10 mm³ porous nickel structure. The structure was annealed at 1370°C for 10 hrs in argon, sandblasted with ceramic beads, and ultrasonically cleaned to form a nickel template. The template was placed in a tube furnace, heated at 100°C/min to 1000°C in Ar (180 mL/min) + H₂ (200 mL/min), held for 30 min, then styrene (0.254 mL/h) was introduced for 1 hr CVD growth. H₂ was shut off and products cooled in argon (50 mL/min) to room temperature to yield 3D graphene on the nickel template. The template was then immersed in 3 mol/L HCl refluxed at 80°C until fully dissolved, washed, and dried to yield a three-dimensional porous graphene structure replicating the nickel template shape.

A periodic ordered porous nickel structure (unit size 1 mm, porosity 75%) was fabricated from pure nickel powder (30-50 µm, spherical) by direct metal laser sintering (250 W, 700 mm/s, 0.02 mm layer thickness, 0.08 mm scanning interval) in argon, yielding a 20×20×10 mm³ porous nickel structure. The structure was annealed at 1370°C for 12 hrs in argon, sandblasted with ceramic beads, and ultrasonically cleaned. The nickel template was heated at 100°C/min to 1000°C in Ar (180 mL/min) + H₂ (200 mL/min), held for 45 min, then styrene (0.508 mL/h) was introduced for 0.5 hr CVD growth. H₂ was shut off and products cooled in argon to yield 3D graphene on the nickel template. The template was then dissolved in corrosive solution to yield a three-dimensional porous graphene structure.

A periodic ordered porous nickel structure (unit size 0.5 mm, porosity 50%) was fabricated from pure nickel powder (5-20 µm, spherical) by selective laser melting (200 W, 500 mm/s, 0.01 mm layer thickness, 0.08 mm scanning interval) in argon, yielding a 20×20×10 mm³ porous nickel structure. The structure was annealed at 1370°C for 10 hrs in argon, sandblasted with ceramic beads, and ultrasonically cleaned to form a nickel template. The template was placed in a tube furnace, heated at 100°C/min to 1000°C in Ar (180 mL/min) + H₂ (200 mL/min), held for 30 min, then styrene (0.254 mL/h) was introduced for 1 hr CVD growth. H₂ was shut off and products cooled in argon (50 mL/min) to room temperature to yield 3D graphene on the nickel template. The template was then immersed in 3 mol/L HCl refluxed at 80°C until fully dissolved, washed, and dried to yield a three-dimensional porous graphene structure replicating the nickel template shape.

A periodic ordered porous nickel structure (unit size 1 mm, porosity 75%) was fabricated from pure nickel powder (30-50 µm, spherical) by direct metal laser sintering (250 W, 700 mm/s, 0.02 mm layer thickness, 0.08 mm scanning interval) in argon, yielding a 20×20×10 mm³ porous nickel structure. The structure was annealed at 1370°C for 12 hrs in argon, sandblasted with ceramic beads, and ultrasonically cleaned. The nickel template was heated at 100°C/min to 1000°C in Ar (180 mL/min) + H₂ (200 mL/min), held for 45 min, then styrene (0.508 mL/h) was introduced for 0.5 hr CVD growth. H₂ was shut off and products cooled in argon to yield 3D graphene on the nickel template. The template was then dissolved in corrosive solution to yield a three-dimensional porous graphene structure.

A periodic ordered porous nickel structure (unit size 0.5 mm, porosity 50%) was fabricated from pure nickel powder (5-20 µm, spherical) by selective laser melting (200 W, 500 mm/s, 0.01 mm layer thickness, 0.08 mm scanning interval) in argon, yielding a 20×20×10 mm³ porous nickel structure. The structure was annealed at 1370°C for 10 hrs in argon, sandblasted with ceramic beads, and ultrasonically cleaned to form a nickel template. The template was placed in a tube furnace, heated at 100°C/min to 1000°C in Ar (180 mL/min) + H₂ (200 mL/min), held for 30 min, then styrene (0.254 mL/h) was introduced for 1 hr CVD growth. H₂ was shut off and products cooled in argon (50 mL/min) to room temperature to yield 3D graphene on the nickel template. The template was then immersed in 3 mol/L HCl refluxed at 80°C until fully dissolved, washed, and dried to yield a three-dimensional porous graphene structure replicating the nickel template shape.

A periodic ordered porous nickel structure (unit size 1 mm, porosity 75%) was fabricated from pure nickel powder (30-50 µm, spherical) by direct metal laser sintering (250 W, 700 mm/s, 0.02 mm layer thickness, 0.08 mm scanning interval) in argon, yielding a 20×20×10 mm³ porous nickel structure. The structure was annealed at 1370°C for 12 hrs in argon, sandblasted with ceramic beads, and ultrasonically cleaned. The nickel template was heated at 100°C/min to 1000°C in Ar (180 mL/min) + H₂ (200 mL/min), held for 45 min, then styrene (0.508 mL/h) was introduced for 0.5 hr CVD growth. H₂ was shut off and products cooled in argon to yield 3D graphene on the nickel template. The template was then dissolved in corrosive solution to yield a three-dimensional porous graphene structure.

A periodic ordered porous nickel structure (unit size 0.5 mm, porosity 50%) was fabricated from pure nickel powder (5-20 µm, spherical) by selective laser melting (200 W, 500 mm/s, 0.01 mm layer thickness, 0.08 mm scanning interval) in argon, yielding a 20×20×10 mm³ porous nickel structure. The structure was annealed at 1370°C for 10 hrs in argon, sandblasted with ceramic beads, and ultrasonically cleaned to form a nickel template. The template was placed in a tube furnace, heated at 100°C/min to 1000°C in Ar (180 mL/min) + H₂ (200 mL/min), held for 30 min, then styrene (0.254 mL/h) was introduced for 1 hr CVD growth. H₂ was shut off and products cooled in argon (50 mL/min) to room temperature to yield 3D graphene on the nickel template. The template was then immersed in 3 mol/L HCl refluxed at 80°C until fully dissolved, washed, and dried to yield a three-dimensional porous graphene structure replicating the nickel template shape.

A periodic ordered porous nickel structure (unit size 1 mm, porosity 75%) was fabricated from pure nickel powder (30-50 µm, spherical) by direct metal laser sintering (250 W, 700 mm/s, 0.02 mm layer thickness, 0.08 mm scanning interval) in argon, yielding a 20×20×10 mm³ porous nickel structure. The structure was annealed at 1370°C for 12 hrs in argon, sandblasted with ceramic beads, and ultrasonically cleaned. The nickel template was heated at 100°C/min to 1000°C in Ar (180 mL/min) + H₂ (200 mL/min), held for 45 min, then styrene (0.508 mL/h) was introduced for 0.5 hr CVD growth. H₂ was shut off and products cooled in argon to yield 3D graphene on the nickel template. The template was then dissolved in corrosive solution to yield a three-dimensional porous graphene structure.