One-pot synthesis of lignin biochar supported Ni for catalytic pyrolysis of Chlorella vulgaris and its model compounds: The formation mechanism of aromatic hydrocarbons

A novel catalyst of lignin biochar supported Ni was prepared through one-pot pyrolysis for the catalytic pyrolysis of Chlorella vulgaris. The catalysts with various Ni loading ratios were rich in functional groups with surface areas of 290.87–458.97 m²/g and average micropore sizes of 0.47–0.56 nm. The in-situ reduction during catalyst preparation yielded 33.13 % of Ni⁰ with average particle size of 37.57 nm. The selectivity of benzene, toluene, and xylene (BTX) from the catalytic pyrolysis of the microalgae reached up to 75.62 % with the quantitative yield of benzene of 58.01 mg/g. The catalytic pyrolysis of the microalgae model compounds (rapeseed oil, glucose, soybean protein, and several amino acids) revealed high catalytic activity for the production of aromatic hydrocarbons based on glucose and soybean protein with 95.72 % and 90.75 % in selectivity, respectively. The study on model compounds conversion elucidated the formation mechanism of aromatic hydrocarbons by removal of heteroatoms (N and O).