Preparation and characterization of char supported Ni[sbnd]Cu nanoalloy catalyst for biomass tar cracking together with syngas-rich gas production

Abstract

In order to realize the efficient biomass tar cracking into syngas-rich gases, several Aspen wood char (ASC) supported metal catalysts, including the Ni/ASC, Cu/ASC and bimetallic Ni-Cu/ASC catalysts, were synthesized with the method of one-step pyrolysis. The structure of the NiCu/ASC catalyst with NiCu nanoalloy encapsulated in carbon nanofibers (CNFs) was observed on the basis of the XRD, SEM and TEM analysis. The catalytic performances of the prepared catalysts on tar cracking were assessed in a two-stage fixed-bed pyrolysis-cracking/reforming device at the catalytic cracking temperatures of 600-800 °C. In a comparison to the single metal catalysts, the bimetallic Ni-Cu/ASC catalyst exerted a better performance on tar removal and possessed a higher selectivity to H2 and CO. The tar conversion efficiency and syngas (H2 + CO) yield, over the NiCu/ASC catalyst at 800 °C, reached up to 93.2% and 581.07 ml/g with the total volumetric content of 72.2% together with H2/CO of 1.1, respectively. The Ni-Cu/ASC catalyst resulted in the lowest contents of two-ring and three-ring aromatics accompanied with highest contents of one-ring aromatics in tar. The Ni-Cu/ASC catalyst was reasonably stable because of its good resistance to sintering and carbon deposition.