One-step synthesis of biomass activated char supported copper nanoparticles for catalytic cracking of biomass primary tar

Abstract

Activated char supported copper nanocatalysts were synthesized directly by one-step pyrolysis of CuCl2 impregnated biomass together with ZnCl2 as activation agent and applied to the cracking of biomass primary tar in a dual-stage reactor. The characterization of the obtained catalysts using XRD, SEM-EDX, TEM and N2 adsorption-desorption indicated CuCl2 can be reduced to Cu0 nanoparticles as active sites, and the presence of ZnCl2 can significantly enlarge the surface area of biomass char to improve the dispersion of copper nanoparticles. A large number of micropores and mesopores were formed during the synthesis process, which also helps to adsorb tar molecules and prolong the reaction time. The prepared nanocatalysts exhibited excellent catalytic activity in the cracking of primary biomass tar as a result of the combining effect of CuCl2 and ZnCl2, and a high tar conversion efficiency of 94.5% was obtained using RHC-1.0Cu1·0Zn at 800 °C. The yields of H2, CH4, CO and the total gas product increased significantly as a result of the tar reforming reactions using the activated char supported catalysts. GC-MS analysis illustrated that the biomass primary tar was mainly decomposed into oxygenated aromatic compounds and light tar compounds over the biomass char supported copper nanocatalysts.