Xiaopeng Shi,Pan Li,Xianhua Wang,Jiande Song,Shuqi Fang,Chun Chang,Shusheng Pang
The main purpose of this work was to explore the effect of metal modified biochar and multi-catalysts on improving the quality of products by microwave pyrolysis (MVP) of biomass. Single-component catalysts and multi-catalysts were prepared by Zn/Zr impregnation methods. The prepared catalysts were evaluated by XRD , BET, FT-IR and SEM. The properties, composition and product distribution of bio-oil and bio-syngas were analyzed. The results showed that ZSM-5 obtained more bio-oil (42.16 wt%) at the expense of gas product yield, and BC obtained the highest gas yield (43.10 wt%). Zn promoted the selectivity of aromatic hydrocarbons in bio-oil, Zr could effectively improve the yield of syngas and upgrading bio-oil, respectively. Zr-modified multi-catalyst was prepared, and the highest syngas yield (91.54 vol%) and aromatic hydrocarbon products were obtained. Among them, the selectivity of monocyclic aromatic hydrocarbons (MAHs) reached 21.82%. The mechanism of MVP of biomass under the effect of Zn/Zr modified different catalysts was proposed. The study has successfully demonstrated an approach for producing high-value bio-oil and bio-syngas from microwave multi-catalyst pyrolytic system.
Xiubo Xie,Ming Chen,Peng Liu,Jiaxiang Shang,Tong Liu
Nickel sulfides decorated reduced graphene oxide (rGO) has been produced by co-reducing Ni 2+ and graphene oxide (GO), and is subsequently ball milled with Mg nanoparticles (NPs) produced by hydrogen plasma metal reaction (HPMR). The nickel sulfides of about 800 nm completely in situ change to MgS, Mg 2 Ni and Ni multiple catalysts after first hydrogenation/dehydrogenation process at 673 K. The Mg-5wt%NiS/rGO nanocomposite shows the highest hydrogen desorption kinetics and capacity properties, and the catalytic effect order of the additives is NiS/rGO, NiS and rGO. At 573 K, the Mg-NiS/rGO nanocomposite can quickly desorb 3.7 wt% H 2 in 10 min and 4.5 wt% H 2 in 60 min. The apparent hydrogen absorption and desorption activation energies of the Mg-5wt%NiS/rGO nanocomposite are decreased to 44.47 and 63.02 kJ mol −1 , smaller than those of the Mg-5wt%rGO and Mg-5wt%NiS samples. The best hydrogen desorption properties of the Mg-5wt%NiS/rGO nanocomposite can be explained by the synergistic catalytic effects of the highly dispersed MgS, Mg 2 Ni and Ni catalysts on the rGO sheets, and the more nucleation sites between the catalysts, rGO sheets and Mg matrix.