Role of O-containing functional groups in biochar during the catalytic steam reforming of tar using the biochar as a catalyst

Abstract

Tar formation is practically unavoidable during gasification. Catalytic tar forming is one of the most promising techniques for producing high-quality syngas at a commercial scale. Biochar has great potential to be used as a catalyst for the removal of tar from the syngas produced from the pyrolysis/gasification of biomass. The structure of biochar is a critical factor affecting its catalytic performance. This study investigates the role of O-containing functional groups in biochar during steam reforming of tar using biochar as a catalyst. Mallee wood biochar (106–250 μm) was activated in H2O for different times (0–50 min) and then used as a catalyst for the steam reforming of tar at 800 °C. The chemical structural features of biochars were characterized with Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that H2O activation increased the concentration of O-containing functional groups, mainly the aromatic CO structures in biochar, which enhanced the catalytic destruction of tar. During the catalytic reforming of tar, the content of aromatic CO groups decreased while the catalyst activity decreased. It is believed that the aromatic CO functional groups in biochar play a vital role in the steam reforming of tar.