Metal-organic framework derived nitrogen-doped porous carbon@graphene sandwich-like structured composites as bifunctional electrocatalysts for oxygen reduction and evolution reactions

By Shengwen Liu, Haimin Zhang, Qian Zhao, Xian Zhang, Rongrong Liu, Xiao Ge, Guozhong Wang, Huijun Zhao, Weiping Cai. 2016

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Abstract In this work, we have successfully prepared sandwich-like structured N-doped porous carbon@graphene composites (N-PC@G) derived from sandwich-like structured zeolitic imidazolate framework@graphene oxide (ZIF-8@GO). ZIF-8@GO was obtained by in situ controllable growth of ZIF-8 nanocrystals on both surfaces of graphene oxide (GO) sheets with different contents. Experimental results demonstrate that N-PC@G-0.02 (representing GO amount of 0.02 g in reaction precursors) obtained at 900 °C possesses high surface area (1094.3 m 2  g −1 ), bimodal-pore structure (micropores and mesopores) and high graphitization degree, exhibiting great potential as a bifunctional electrocatalyst for both ORR and OER. Compared to commercial Pt/C catalyst, the N-PC@G-0.02 shows superior electrocatalytic activity with onset and half-wave potentials of 1.01 V and 0.80 V ( vs. RHE), respectively, better durability and high resistance to methanol crossover effect toward ORR in alkaline media. Also, the metal-free N-PC@G-0.02 also exhibits high electrocatalytic activity of OER, comparable to commercial RuO 2 catalyst. The superior ORR and OER performance could be due to a synergistic effect between ZIF-8 derived porous carbon and graphene with regard to structure and composition of N-PC@G-0.02 with high surface area, porous structure, and suitable N doping level and type, boosting the catalytic active sites, mass transport and electron transfer.

Subfields: Electrical and Electronic Engineering, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/25637923419c1701c4cd34a0f8a8285cba6b1a91