The cell for which the cell reaction is ${\mathrm{H}}_2+{\mathrm{Cu}}^{2+}⟶2{\mathrm{H}}^{+}+\mathrm{Cu}$ is represented as

Oxidation occurs at anode: 

${\mathrm{H}}_2\to 2{\mathrm{H}}^{+}+2{\mathrm{e}}^{-}$

Reduction occurs at cathode:

${\mathrm{Cu}}^{2+}+{\mathrm{e}}^{-}\to \mathrm{Cu}$

The Galvanic cell is represented as 

$\mathrm{Pt}, {\mathrm{H}}_2(1 \mathrm{atm})\overline{){\mathrm{H}}^{+}\overline{)\overline{){\mathrm{Cu}}_{\left(\mathrm{aq}\right)}^{2+}\overline{)\mathrm{Cu}}}}}$