The Controlled Fabrication Of MOFs-Derived Carbon-Based Materials And Their Catalytic Performance

MOFs-derived porous carbon-based materials that possess the advantages of large specific surface area,high porosity,good conductivity,high structural stability,high resistance to corrosion,tunable structure and functionality etc.,have recently become one of the most important research hotspots in the field of heterogeneous catalysis.Herein,we systematically study the controlled synthetic methods to various MOFs-derived porous carbon-based materials and their catalytic performance in different reactions.Through the rational design of control experiments,systematic structure characterization and theoretical computational simulation,we preliminarily disclose the nature of catalytically active sites and the structure-performance correlations within the series of as-prepared MOFs-derived porous carbon-based materials.(1)By the controlled pyrolysis of Zn-Co bimetallic PBAs,cobalt-embedded N-doped porous carbon submicrospheres can be successfully prepared.Towards the reduction of p-nitrophenol,the optimized catalyst shows more excellent activity than certain precious-metal-based catalysts.A series of control experiments and corresponding characterization results confirm the origin of active sites within the catalyst—one type was totally confined into perfect compact carbon layers and the other was partially embedded in carbon layers with small cracks and/or defects.This work might contribute to giving supplementary insight into the nature of catalytically active sites for various metal-loading carbon-based catalysts.(2)Based on the intrinsic traits of ZIF parent such as periodic distribution of metallic node and high porosity,N-doped porous carbon incorporating atomically dispersed Ru sites can be obtained by the controlled pyrolysis of Ru-doped ZIF precursors.The optimized catalyst exhibited high-performance HER activity and stability,which is superior to the commercial Pt/C benchmarking.Combined with the DFT calculations,the poisoning/recovery tests demonstrate the leading role of atomically Ru sites during the electrocatalysis.This work might provide a powerful guidance to develop novel MOFs-derived carbon-based catalysts incorporating single metal sites,and contribute to disclosing the nature of active sites and possible reaction mechanism.(3)By the hydrolysis of ZIF-8 in Co(?)solution and the following pyrolysis of the obtained intermediates,the ultrathin N-doped carbon nanosheets containing cobalt nanoparticles can be successfully prepared.Compared with those MOFs-derived bulk particulate-like counterparts,this cobalt-embedded ultrathin N-doped carbon nanosheets exhibited increased exposure of cobalt species and favorable mass transfer during the HER,which mainly be attributed to the ultrathin morphological feature and suitable porous texture.This work may provide a better experimental support for the rational design of MOFs-derived carbon-based catalysts and the deep insights into the correlation between structure and performance.