The influence of preparation method of char supported metallic Ni catalysts on the catalytic performance for reforming of biomass tar

Abstract

Summary The char‐supported nickel catalysts prepared by wet impregnation and precipitation‐deposition methods under different nickel loadings and catalytic temperatures for catalytic reforming of rice husk tar were investigated. The influences of preparation methods on the physicochemical properties of catalysts and catalytic activity towards tar conversion and gas yield were studied. The results showed that char‐supported metallic Ni catalysts can be directly used without a reduction process because of carbon thermal reaction during calcination. The preparation method had a significant influence on the porosity and Ni dispersion of catalysts. The addition of Ni to char improved the specific surface area from 60 m2 g−1 to 346.8 m2 g−1 because of activation effect of nickel nitrate on char pore structure. The precipitation‐deposition method produced higher surface area, smaller Ni nanoparticulates with more corner and step sites, as well as more concentrated size distribution than those of wet impregnation method, leading to higher catalytic activity, in terms of high tar conversion efficiency (83%) and increasing syngas yield. The selectivity to phenols and naphthalene for precipitation‐deposited catalysts was strengthened, and the relative content of heavy tars was decreased remarkably. The increasing H2 yield and concentration were indicative of efficient conversion of macromolecular organic matters into small molecules gases. In addition, the precipitation‐deposited catalyst exhibited weaker Ni sintering after reaction. The catalytic cracking temperature of 800°C and Ni loading of 10 wt% exhibited the best catalytic effects on gas distribution and tar conversion.

Fibrous spherical Ni‐M/ZSM‐5 (M: Mg, Ca, Ta, Ga) catalysts for methane dry reforming: The interplay between surface acidity‐basicity and coking resistance

“…A detailed examination reveals diffractograms within peak range of 2θ = 7‐10° and 22‐25°, which is allotted to ZSM‐5 phase (JCPDS file number 37‐359) . In addition, formation of NiO cubic phase around 2θ = 37.28, 43.2 and 62.5, which corresponds to the (111), (200) and (220) reflections were observed for all supported Ni catalysts . All promoted catalysts portrayed different NiO crystallites sizes (see Table ).…”

Simultaneous Catalytic Conversion of Acid-Pretreated Biomass into High-Quality Syngas and Bio-oil at Mild Temperature

“…The catalytic pyrolysis was performed under ambient pressure in a two-stage downdraft fixed-bed reactor, as shown in our previous work. 29 In detail, prior to the experiment, a 2 g AC catalyst was loaded into a quartz tube reactor. Two gram samples were enclosed in a quartz boat and hung from the roof of the reactor.…”

Enhanced Low-temperature Catalytic Decomposition Performance of Naphthalene over Hydrothermal Carbon-based Nanomaterials with a Hierarchical Heterostructure

“…Moreover, the architecture can reduce the diffusion resistance and shorten the diffusion lengths, thus contributing to faster kinetics and high-rate reactions. According to Xu et al, 34 the biochar-supported nickel catalysts with hierarchical pores facilitated the adsorption for tar macromolecules to active sites and reforming reaction.…”