Temperature–Controlled hydrothermal hydrogenation of palmitic acid to alkanol or alkanes over Co@CN–x catalysts derived from ZIF–67

Abstract

Biomass is one of the most abundant and important renewable resource. The selective hydrothermal hydrogenation of microalgae-based bio–oil to produce fine chemicals and fuels such as alkanols or alkanes has been widely studied in the past decade. However, developing a low–cost catalyst with high hydrogenation activity and hydrothermal stability remains a huge challenge. Here, we have constructed a new type of catalyst (Co@CN–900) to achieve highly selective preparation of alkanol (1-hexadecanol, 97.4 %, 220 °C, 30 min) and alkanes (composed of n-pentadecane, n-hexadecane, and cracking alkanes, 96.8 %, 280 °C, 300 min) from temperature–controlled hydrothermal hydrogenation of palmitic acid (a model compound of microalgae-based bio–oil). A large number of N–doped carbon nanotubes confined Co nanoparticles (NPs) catalysts are obtained through the simple one–step pyrolysis of ZIF–67. Catalysts with the special structures exhibit extremely high activity in the hydrothermal hydrogenation of palmitic acid, surpassing the commercial Pt/C catalyst, especially in the conversion rate of palmitic acid, the generation rate of 1-hexadecanol and n-hexadecane. More importantly, no significant deactivation was observed after 5 cycles, demonstrating relatively strong hydrothermal stability.