Effect of synthesis temperature on catalytic activity and coke resistance of Ni/bio-char during CO2 reforming of tar

• Published in: International journal of hydrogen energy 2021-08, Vol.46 (54), p.27543-27554
• Main Authors: Chen, Xinfei, Ma, Xiaoqian, Peng, Xiaowei, Chen, Liyao, Lu, Xiaoluan, Tian, Yunlong
• Format: Article
• Language: English
• Subjects: CO2 reforming; Ni/bio-char; One-pot HTC synthesis method; Synthesis temperature; Tar
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.06.011

Understanding how the synthesis parameters affect nickel particle distribution is critical to the synthesis of Ni/bio-char with excellent catalytic performance. In this work, the influence of synthesis temperature on catalytic activity and coke resistance of Ni/bio-char during CO2 reforming of tar was explored. With the increase of synthesis temperature from 200 °C to 250 °C, the dispersion of nickel precursor into bio-char was promoted, resulting in an increase in crystallite size of metallic nickel particle from 51.98 nm to 62.45 nm. Besides, parts of the metallic nickel particles were oxidized to nickel oxides, providing more lattice oxygen to oxidize the coke deposited on the catalyst. However, further increasing the synthesis temperature to 300 °C would aggravate the oxidation of active nickel particles. The increase in crystallite size of nickel oxide particle from 23.25 nm to 43.38 nm could block the pore structure and hinder the access of reactants, resulting in a drop in the tar conversion rate from 40-51% to 13–27%. [Display omitted] •High synthesis temperature promoted dispersion of nickel precursor into bio-char.•The excessive increase of synthesis temperature aggravated the oxidation of nickel.•Optimizing synthesis temperature can improve catalyst activity and coke resistance.