The catalytic transformation of renewable fatty acids into value-added fatty alcohols without the use of gaseous hydrogen is a versatile technique for the utilization of microalgae and waste cooking oil, where Cu-based catalysts are considered to be the most suitable candidate. However, the interpretation of the structure–reactivity relationship caused by different crystal types of carriers and the metal–support interface is not well understood. Herein we synthesized ZrO2-supported Cu nanoparticle catalysts via different preparation methods and reduction temperatures under similarly exposed surface facets and Cu valency but different polymorphic phases of ZrO2 (monoclinic ZrO2: m-ZrO2; tetragonal ZrO2: t-ZrO2) and the metal–support interface. Interestingly, the as-synthesized Cu/t-ZrO2 catalysts showed remarkably better catalytic performance than Cu/m-ZrO2 for the in situ hydrogenation of lauric acid in the methanol–water system. Combined experimental and density functional theory (DFT) calculation results ascribed the lower efficiency of m-ZrO2 as a carrier to weakly adsorbed reactant and intermediate molecules as well as the absence of an oxygen vacancy in the crystal phase. The interface-rich Cu/t-ZrO2 catalysts displayed higher activity normalized to the surface-exposed Cu sites toward lauryl alcohol production than the interface-deficient counterparts. DFT calculation results further revealed that this metal–support interface plays an important role in promoting the C–O bond or H–H bond cleavage in two possible reaction routes, thus reducing the activation barrier of the overall reaction.

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As-synthesized Ni-based Lewis acidic catalysts, with tunable concentrations of β-Ni(OH) 2 and γ-NiOOH, were tested on the conversion of sugars to methyl lactate (MLA) in near-critical methanol solutions. The concentration of γ-NiOOH increased with an increase in the Ni(NO 3 ) 2 •6H 2 O/2-methylimidazole (Ni/2-Hmim) molar ratio. Compared to β-Ni(OH) 2 , the γ-NiOOH showed more mesopores in the catalyst, which facilitated the diffusion of reactant and products. Ni/2-Hmim-4 [Ni(NO 3 ) 2 • 6H 2 O/2-methylimidazole molar ratio = 4] exhibited the best catalytic activity. Under optimal conditions (180 °C for 12 h), the highest MLA yield was 41.9% on the conversion of glucose. Ni/2-Hmim-4 was employed to convert disaccharides to MLA. Notably, for sucrose, the reaction afforded a 38.7% MLA yield at 200 °C for 12 h. The catalyst was reusable for at least three cycles.

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