LAUSR

Abstract Mesoporous Co@carbon nanoplates, derived from zeolitic imidazolate framework-67 (ZIF-67) crystals, were facilely prepared via a "silica-assisted" strategy. Through introducing and removing colloidal silica during synthetic process, the Co@carbon nanocomposites (CoOx@CS) exhibited mesopores characteristic and nanoplates. By comparison, the Co@carbon nanocomposites (CoOx@C), obtained by a direct pyrolysis of ZIF-67, exhibited micropores characteristic and assembled microsphere. In catalytic decomposition of ammonia, it was found that the CoOx@CS nanocomposites showed excellent catalytic activity. Nearly 60% NH3 conversion was achieved at 500 °C with a space velocity of 6000 h−1, whereas only ~ 30% NH3 conversion was achieved under the same reaction conditions for CoOx@C nanocomposites. The enhanced activity should be attributed to mesoporous characteristic, nanoplates-like microstructure and basicity of carbon support. This study provides new insights into the development of controlling the structural orders of MOFs-derived carbon-based materials.