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Detailed XPS analysis confirmed the disappearance of unstable pyridinic N in cys-N-rGO and the reduction degree threshold of N-rGO for effective cysteamine modification to take place.
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XPS PEAK SHIFT REDUCED GRAPHENE OXIDE SERIES
A series of N-doped rGO (N-rGO) precursors with different levels of oxygen groups were synthesized by adjusting the amount of reducing agent (hydrazine), followed by subsequent covalent attachment of cysteamine via the thermal thiol-ene click reaction to yield different ratios of mixed functional groups including N (pyrrolic N, graphitic N, and aminic N), S (thioether S, thiophene S, and S oxides), and O (hydroxyl O, carbonyl O, and carboxyl O) on the reduced GO surface. Controllable modulation of chemical multifunctionality was achieved by simultaneous nitrogen doping and gradual chemical reduction of graphene oxide (GO) using ammonia and hydrazine, followed by covalent attachment of amino-terminated thiol molecules using the thiol-ene click reaction. We present a simple chemical approach to obtain bulk quantities of multifunctionalized reduced graphene oxide (rGO) that combines chemical doping and functionalization using the thiol-ene click reaction.
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The synthesis of graphene materials with multiple surface chemistries and functionalities is critical for further improving their properties and broadening their emerging applications.