Natural DNA-derived highly-graphitic N, P, S-tridoped carbon nanosheets for multiple electrocatalytic applications

In the electrocatalytic oxygen reduction and hydrogen evolution reactions (ORR/HER), metal-free carbon-based materials presented great potentials as alternatives to Pt because of their flexible adjustability of electronic and geometric properties. The pursuit of high-performance carbons demand for high-level doping, large surface area and high graphitization, but the improvement of the former two aspects would inevitably impair the third one, which seems a contradictive proposition. Herein, by a facile “mix-and-pyrolyze” method, natural DNA was first developed to synthesize N, P, S-tridoped carbons (NPSC) with porous sheet structures, high graphitization, large surface areas and abundant high-quality dopants simultaneously. Thus, the newly-prepared NPSC displays superior alkaline ORR performance comparable to Pt/C together with excellent acidic activity and better stability. Meanwhile, NPSC is one of most active acidic HER catalysts and the best alkaline HER catalyst among carbon counterparts. Density function theory computation reveled the origins of superior performance are attributed to positively charged C sites neighboring to S for ORR and P sites for HER because of DNA-derived advantaged structural features. The as-fabricated rechargeable zinc–air battery based on current tridoped carbon has closed peak power density and specific capacity but much better charge–discharge stability compared with Pt/C.