▎ 摘　　要

NOVELTY - Single-crystal nitrogen-functionalized graphene nano-flake comprises 2 atomic% to at least 35 atomic% of total functionalized nitrogen. USE - The single-crystal nitrogen-functionalized graphene nano-flake is useful: in a multilayer composite for a polymer electrolyte membrane fuel cell (claimed), which is useful as a source of electrical energy for portable devices, stationary power sources, and electric vehicles; and as non-noble metal catalyst. ADVANTAGE - The single-crystal nitrogen-functionalized graphene nano-flake can be easily prepared with high purity, crystallinity and stability in a cost-effective manner. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) producing the single-crystal nitrogen-functionalized graphene nano-flake, comprising providing a carbon source, providing a nitrogen source, injecting the carbon source into a thermal plasma system dissociating the carbon source into carbon atomic species, transporting the carbon atomic species through a controlled nucleation zone to produce a single-crystal graphene, injecting the nitrogen source into the thermal plasma system dissociating the nitrogen source into nitrogen active species, and transporting the nitrogen atomic species through the controlled flow/temperature zone to contact the single-crystal graphene to produce the single-crystal nitrogen-functionalized graphene nano-flake; and (2) a multilayer composite for a polymer electrolyte membrane fuel cell, comprising a substrate and a layer of single-crystal nitrogen-functionalized graphene nano-flakes on the substrate.