H2 production by steam reforming of Saccharina japonica-derived liquefied oils on NixCuy hydrotalcite-derived catalysts

H-2 is highlighted as a sustainable energy resource, and mainly produced by steam reforming of fossil fuels, which emit greenhouse gases. Marine biomass can be an alternative because of high productivity and carbon neutrality compared to terrestrial biomass. In this work, we studied bio-oil from Saccharina japonica (macroalgae) as a renewable H-2 resource by steam reforming on NiCu hydrotalcite-derived catalysts (NixCu1.5-xMg1.5Al1.0). After the hydrothermal liquefaction of S. japonica, minerals were removed by the desalting process. GC-MS showed bio-oil mainly consists of ketone and N-containing compounds. Increasing Cu content improved the reducibility of Ni, evidenced by H-2-TPR and XPS, suggesting the synergetic interaction between Ni and Cu. Chemisorption showed the catalyst had the smallest particle sizes (similar to 19 nm) at 1 to 1 Ni:Cu atomic ratio. As for steam reforming of bio-oil, NixCu1.5-xMg1.5Al1.0 catalysts, except Cu1.5-xMg1.5Al1.0, were stable with >89% of carbon conversion and H-2 selectivity of 76-78% during 5 h. Especially, at 1:1 Ni:Cu atomic ratio, the catalyst maximized H-2 production rates with the highest H-2/CO ratio of 28. It suggests that designing small NiCu particles is critical for H-2 production. In summary, NixCu1.5-xMg1.5Al1.0 catalysts are promising for H-2 production by the steam reforming of the bio-oil from macro algae. (C) 2022 The Authors. Published by Elsevier Ltd.

Automated summary

This study focuses on marine biomass as an alternative sustainable energy resource, specifically investigating the use of bio-oil from Saccharina japonica as a renewable H-2 source. The study demonstrates the importance of catalyst design in maximizing H-2 production rates.