Nitrogen species from Spirulina platensis derived bio-oil enhance catalytic activity of cobalt catalysts for hydrogenation

High nitrogen content in Spirulina platensis -derived bio-oil is a highly undesirable feature in upgrading of bio-oil to biofuel via hydrodeoxygenation . However, the nitrogen species could be potentially used as dopant for tailoring the catalytic behaviors of metallic sites in heterogeneous catalysts . In this study, the nitrogen species in the bio-oil from hydrothermal carbonization (HTC) of Spirulina platensis was used to modify Co-based catalyst for enhancing their catalytic activity for hydrogenation of o -chloronitrobenzene ( o -CNB). The results showed that the introduction of N species not only promoted dispersion of Co particles via formation of Co–N sites, but also generated extra pores and significantly increased H 2 uptake. The abundant Co–N sites, high dispersion of Co and higher surface area of N-doped catalyst (CoFeAl–N) jointly contributed to the enhanced catalytic activity for hydrogenation of o -CNB, achieving the yield of 90.3% for o -chloroaniline ( o -CA) and lowering the activation energy from 63.0 kJ mol −1 (with N-free CoFeAl catalyst) to 55.1 kJ mol −1 . The effectiveness of introducing nitrogen for enhancing catalytic activity for hydrogenation of o -CNB was also confirmed in the experiments for doping Co/Al 2 O 3 (prepared via impregnation) and CoAl (prepared via co-precipitation) catalysts with the Spirulina platensis derived bio-oil.