▎ 摘　　要

This study highlights the challenges and opportunities of Hydrothermal Liquefaction (HTL) of Cladophora glomerata. It suggests functionalized graphene oxide/polyurethane (F-GO-PU) composite as the promising metal -free catalysts for sustainable algae upgrading. The catalysts contained three types of functional groups, including methyl (-CH3), vinyl (-CH=CH2), and amine (-NH2), and were completely analyzed by FTIR, XRD, and SEM-EDS in terms of functional groups, crystalline structure, morphology, and surface elemental distribution, respectively. The results showed that F-GO-PU catalysts efficiently suppressed side reactions that would generate non-desired chemicals. Functionalization with vinyl increased the yield of bio-crude oil by about 54% and showed high selectivity for hydrocarbons with a yield of 15.66 wt%. This catalytic activity was due to the existence of stable and accessible Bronsted acid sites plus the hybrid structure of the composite, which enhanced the accommo-dation of reaction intermediates on the surface of the catalyst. Thus, as-prepared F-GO-PU composites may hold great promise as metal-free active phase catalysts to develop algae transformation reactions.