Methane cannot be produced by Wurtz reaction, Kolbes electrolytic method and reduction with $H_{2}$ because, it has one carbon atom.
Pure methane can be produced by the decarboxylation of sodium acetate. $CH _{3} COONa +\underset{\text { soda lime }}{N a O H} \stackrel{ CaO }{\longrightarrow } \underset{\text { metahane }}{ CH _{4}}+ Na _{2} CO _{3}$