Water-soluble triphenylphosphine-derived microgel as the template towards in-situ nitrogen, phosphorus co-doped mesoporous graphene framework for supercapacitor and electrocatalytic oxygen reduction

•Water-soluble PIL microgel was used as a soft template and phosphorus dopant.•Nitrogen, phosphorus co-doped mesoporous graphene framework was obtained.•Its specific area and pore structure could be adjusted with microgel content.•High capacitance and excellent ORR catalytic activity were achieved.

In this work, we endowed the hydrophobic triphenylphosphine (TPP) with vinyl group as a new copolymerization monomer to synthesize water-soluble microgels, in which the hydrophilic and positively charged TPP-derived chain segments are mainly located at the surface. These synthesized microgel is simultaneously used as a soft template and phosphorus dopant to fabricate nitrogen, phosphorus co-doped mesoporous graphene framework (NP-PG) via a facile hydrothermal process containing graphene oxide and ammonia. Self-assembly of graphene oxide sheets and microgels induced by their electrostatic interaction enable a tight contact between them, which would confine the phosphorus doping mostly in the pore walls. The obtained NP-PG, as a metal-free electrocatalyst for oxygen reduction, shows a comparable electrocatalytic activity to commercial Pt/C catalyst with a peak potential of −0.18 V (vs. Ag/AgCl) and long-term durability. Additionally, it can also be used as a supercapacitor electrode to achieve a high specific capacitance of 245 F g−1 at 0.5 A g−1 and 95% of capacitance retention even after 3000 cycles at 5 A g−1.

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