LAUSR

Abstract Hydrogen, one of the green energy resources, has attracted much attention since it can be produced from biomass with zero net CO2 emissions. Supercritical water gasification (SCWG) is an emerging technology for hydrogen production from macroalgae. It enables the elimination of the costly feedstock-drying step. However, a comprehensive review of hydrogen production from macroalgae via SCWG is still limited. Therefore, this article highlights the potential application of SCWG for hydrogen production from macroalgae as an alternative energy source. Firstly, the SCWG of macroalgae, including the fundamental process of SCWG, non-catalytic and catalytic SCWG of macroalgae, are comprehensively reviewed. The critical strategies on SCWG for hydrogen production from macroalgae are also presented. Finally, this paper also highlights the main challenges and future prospective in implementing SCWG of macroalgae for hydrogen production. The overall findings provide new insights for the future guideline related to suitable and highly effective hydrogen production from macroalgae.