NaCl Crystallites as Dual-Functional and Water-Removable Templates To Synthesize a Three-Dimensional Graphene-like Macroporous Fe-N‑C Catalyst

• Published in: ACS catalysis Vol. 7; no. 9; pp. 6144 - 6149
• Main Authors: Wang, Wang, Chen, Wenhui, Miao, Peiyu, Luo, Jin, Wei, Zidong, Chen, Shengli
• Format: Journal Article
• Language: English
• Published: American Chemical Society 01.09.2017
• Subjects: dual functionality; macroporous carbon; water-removable templates; oxygen reduction reaction; mass transfer
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/acscatal.7b01695

Three-dimensional macroporous carbon materials with hierarchical pore structures (3D MPC) have wide applications, but the scale-up synthesis is limited by the cumbersome procedures of template formation and removal. Herein, we show that NaCl crystallites, which form in situ in a lyophilizing process of a NaCl solution containing a carbon precursor and are removable simply through water washing, can act as templates to grow 3D MPC materials with graphene-like ultrathin and mesoporous walls through pyrolitic carbonization. Further, by use of a nitrogen (N)-rich polymer (polyvinylpyrrolidone, PVP) as the carbon precursor and introduction of Fe salt in the precursor, an MPC catalyst with high Fe/N doping content is achieved due to the NaCl crystallites serving as confining agents to simultaneously prevent the large weight loss and N evaporation, a severe problem in usual pyrolytic syntheses of Fe-N-C catalysts. Benefiting from the mass transport convenience of the macropores as indicated by the impedance spectroscopy results, the Fe/N-doped 3D MPC exhibits high catalytic performance toward the oxygen reduction reaction. The dual functionality, facile formation and removal, and reusability of NaCl make the present method a promising way to gain cost-effective porous Fe-N-C catalysts.