The electrochemical synthesis of hydrogen peroxide via the two-electron oxygen reduction reaction (2e^–ORR) offers a green and environment-friendly production method. Here, Pt single-atom catalyst confined in NH₂-UIO-66 was successfully prepared by glow discharge plasma at room temperature, and it was used for the 2e^–ORR. The plasma treated sample exhibited a high H₂O₂ selectivity of 99.86%, surpassing that of the samples prepared by calcination and chemical reduction methods. NH₂-UIO-66 inhibits the growth of Pt particles and improves Pt dispersion. Plasma prevents Pt aggregation due to the low temperature and enhances the interaction between Pt and NH₂-UIO-66 which leads to an outstanding electrocatalytic ORR. This work provides strategies towards single-atom catalysts through the confinement of metal–organic frameworks for electrocatalysis.