From macroalgae to porous graphitized nitrogen-doped ... 2020-5-1 · Enteromorpha prolifera and Ulva lactuca were obtained from the Xiamen Sea, China. FeCl 3 ·6H 2 O (≥99%), ZnCl 2. 2.2. Synthesis of the PGNBCs. PGNBCs were synthesized through direct pyrolysis of the composites of macroalgae, ZnCl 2 and FeCl 3 which as the carbon precursor, pore-forming agent and graphene catalyst agent, respectively.