K2CO3-promoted methane pyrolysis on nickel/coal-char hybrids

Catalytic methane pyrolysis (CMP) is an environmentally benign and promising strategy for hydrogen production. However, one of the important challenges is to creatively design and prepare catalysts with high and stable catalytic activity. To integrate both advantages of traditional metal and carbon catalysts, four effective strategies were proposed to study K2CO3-promoted CMP on nickel/coal-char hybrids in this work, including: (1) Impregnation-Thermal treatment-Mechanical mixing method, (2) Precipitation-Thermal treatment method, (3) Precipitation-In situ thermal treatment (PIT) method, and (4) Precipitation-In situ thermal treatment-Hydrogen reduction method. The results suggest that the addition of K2CO3 is the key factor to promote the catalytic activity and stability of the nickel/coal-char hybrids regardless of the preparation methods, leading to high and stable methane conversion (higher than 65% at 850 degrees C) in the whole 300-min CMP process. Compared to the other three preparation methods, the PIT method is considered to be one simpler and more time-saving process for synthesis of robust catalysts for CMP.