High oxygen content of microalgae-derived bio-oil limits their direct use in modern motors. In this study, instead of noble metal-catalyzed two-step hydrodeoxygenation, MgAl layered double hydroxides/oxides (MgAl-LDH/LDO) with tunable acidic and basic properties are developed for catalyzing the hydrothermal liquefaction (HTL) of microalgae to obtain bio-oil with a low oxygen content. The results show that both MgAl-LDH₃ and MgAl-LDO₃ enhance low O/C bio-oil production through catalyzing both the hydrolysis of cellular compounds and decarboxylation and decarbonylation of biocrude during HTL of microalgae. MgAl-LDH₃ with more acidic sites is more effective at catalyzing the hydrolysis of cellular compounds than MgAl-LDO₃ according to the relative increases of 12.98% and 9.72% of biocrude yields, respectively. However, MgAl-LDO₃ with more basic sites is more efficient in catalyzing the decarboxylation and decarbonylation and amidation of fatty acids to form hydrocarbons, esters, alcohols, and amides, which contributes to a 22.6% decrease of O/C and 28.4% increase of N/C in the bio-oil product, respectively. This work reveals that MgAl-LDH_x and MgAl-LDO_x are efficient at catalyzing not only the hydrolysis of cellular compounds but also the deoxidation of the reaction intermediates to produce low O-containing bio-oil, which might pave the way for its direct use in modern motors.

中文翻译：

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用于低氧生物燃料生产的微藻的 MgAl-LDH/LDO 催化水热脱氧

微藻衍生生物油的高含氧量限制了它们在现代电机中的直接使用。在这项研究中，代替贵金属催化的两步加氢脱氧，开发了具有可调酸碱性的 MgAl 层状双氢氧化物/氧化物 (MgAl-LDH/LDO) 用于催化微藻的水热液化 (HTL) 以获得生物-含氧量低的油。结果表明，MgAl-LDH ₃和MgAl-LDO ₃均通过催化微藻HTL过程中细胞化合物的水解和生物原油的脱羧和脱羰来提高低O/C生物油产量。具有更多酸性位点的MgAl-LDH ₃在催化细胞化合物水解方面比 MgAl-LDO ₃更有效根据生物原油产量的相对增加分别为 12.98% 和 9.72%。然而，具有更多碱性位点的MgAl-LDO ₃更有效地催化脂肪酸的脱羧、脱羰和酰胺化形成烃、酯、醇和酰胺，这有助于O/C降低22.6%，增加28.4%分别在生物油产品中的 N/C。这项工作表明，MgAl-LDH _x和 MgAl-LDO _x不仅能有效催化细胞化合物的水解，还能有效催化反应中间体的脱氧以产生低含氧量的生物油，这可能为其直接作用铺平道路。用于现代电机。