The electrosynthesis from 5‐hydroxymethylfurfural (HMF) is considered a green strategy to achieve biomass‐derived high‐value chemicals. As the molecular structure of HMF is relatively complicated, understanding the HMF adsorption/catalysis behavior on electrocatalysts is vital for biomass‐based electrosynthesis. The electrocatalysis behavior can be modulated by tuning the adsorption energy of the reactive molecules. In this work, the HMF adsorption behavior on spinel oxide, Co3O4 is discovered. Correspondingly, the adsorption energy of HMF on Co3O4 is successfully tuned by decorating with single‐atom Ir. It is observed that compared with bare Co3O4, single‐atom‐Ir‐loaded Co3O4 (Ir‐Co3O4) can enhance adsorption with the CC groups of HMF. The synergetic adsorption can enhance the overall conversion of HMF on electrocatalysts. With the modulated HMF adsorption, the as‐designed Ir‐Co3O4 exhibits a record performance (with an onset potential of 1.15 VRHE) for the electrosynthesis from HMF.
Co-based spinel oxides,which are of mixing valences with the presence of both Co 2+ and Co 3+ at different atom locations,are considered as promising catalysts for the electrochemical oxidation of 5-hydroxymethylfurfural (HMF). Identifying the role of each atom site in the electroxidation of HMF is critical to design the advanced electrocatalysts.Inthis work, we found that Co 2+ Td in Co 3 O 4 is capable of chemical adsorption for acidic organic molecules,a nd Co 3+ Oh play ad ecisive role in HMF oxidation. Thereafter,t he Cu 2+ was introduced in spinel oxides to enhance the exposure degree of Co 3+ and to boost acidic adsorption and thus to enhance the electrocatalytic activity for HMF electrooxidation significantly.
Nickel hydroxide (Ni(OH) 2 )isapromising electrocatalyst for the 5-hydroxymethylfurfural oxidation reaction (HMFOR) and the dehydronated intermediates Ni(OH)O species are proved to be active sites for HMFOR. In this study, Ni(OH) 2 is modified by platinum to adjust the electronic structure and the current density of HMFOR improves 8.2 times at the Pt/Ni(OH) 2 electrode compared with that on Ni(OH) 2 electrode.O perando methods reveal that the introduction of Pt optimizedt he redoxp roperty of Ni(OH) 2 and accelerate the formation of Ni(OH)O during the catalytic process.T heoretical studies demonstrate that the enhanced Ni(OH)O formation kinetics originates from the reduced dehydrogenation energy of Ni(OH) 2 .The product analysis and transition state simulation prove that the Pt also reduces adsorption energy of HMF with optimizeda dsorption behavior as Pt can act as the adsorption site of HMF.O verall, this work here provides as trategy to design an efficient and universal nickel-based catalyst for HMF electro-oxidation, which can also be extended to other Ni-based catalysts such as Ni(HCO 3 ) 2 and NiO.
The electrooxidation of 5‐hydroxymethylfurfural (HMF) offers a promising green route to attain high‐value chemicals from biomass. The HMF electrooxidation reaction (HMFOR) is a complicated process involving the combined adsorption and coupling of organic molecules and OH− on the electrode surface. An in‐depth understanding of these adsorption sites and reaction processes on electrocatalysts is fundamentally important. Herein, the adsorption behavior of HMF and OH−, and the role of oxygen vacancy on Co3O4 are initially unraveled. Correspondingly, instead of the competitive adsorption of OH− and HMF on the metal sites, it is observed that the OH− can fill into oxygen vacancy (Vo) prior to couple with organic molecules through lattice oxygen oxidation reaction process, which could accelerate the rate‐determining step of the dehydrogenation of 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA) intermediates. With the modulated adsorption sites, the as‐designed Vo‐Co3O4 shows excellent activity for HMFOR with the earlier potential of 90 and 120 mV at 10 mA cm−2 in 1 m KOH and 1 m PBS solution. This work sheds insight on the catalytic mechanism of oxygen vacancy, which benefits designing a novel electrocatalysts to modulate the multi‐molecules combined adsorption behaviors.
Electrocatalytic oxidation of 5‐hydroxymethylfurfural (HMF) provides an efficient way to obtain high‐value‐added biomass‐derived chemicals. Compared with other transition metal oxides, CuO exhibits poor oxygen evolution reaction performance, leading to high Faraday efficiency for HMF oxidation. However, the weak adsorption and activation ability of CuO to OH− species restricts its further development. Herein, the CuO–PdO heterogeneous interface is successfully constructed, resulting in an advanced onset‐potential of the HMF oxidation reaction (HMFOR), a higher current density than CuO. The results of open‐circuit potential, in situ infrared spectroscopy, and theoretical calculations indicate that the introduction of PdO enhances the adsorption capacity of the organic molecule. Meanwhile, the CuO–PdO heterogeneous interface promotes the adsorption and activation of OH− species, as demonstrated by zeta potential and electrochemical measurements. This work elucidates the adsorption enhancement mechanism of heterogeneous interfaces and provides constructive guidance for designing efficient multicomponent electrocatalysts in organic electrocatalytic reactions.
BackgroundMice deficient in the LDL receptor (Ldlr −/− mice) have been widely used as a model to mimic human atherosclerosis. However, the time-course of atherosclerotic lesion development and distribution of lesions at specific time-points are yet to be established. The current study sought to determine the progression and distribution of lesions in Ldlr −/− mice.Methodology/Principal FindingsLdlr-deficient mice fed regular chow or a high-fat (HF) diet for 0.5 to 12 months were analyzed for atherosclerotic lesions with en face and cross-sectional imaging. Mice displayed significant individual differences in lesion development when fed a chow diet, whereas those on a HF diet developed lesions in a time-dependent and site-selective manner. Specifically, mice subjected to the HF diet showed slight atherosclerotic lesions distributed exclusively in the aortic roots or innominate artery before 3 months. Lesions extended to the thoracic aorta at 6 months and abdominal aorta at 9 months. Cross-sectional analysis revealed the presence of advanced lesions in the aortic sinus after 3 months in the group on the HF diet and in the innominate artery at 6 to 9 months. The HF diet additionally resulted in increased total cholesterol, LDL, glucose, and HBA1c levels, along with the complication of obesity.Conclusions/SignificanceLdlr-deficient mice on the HF diet tend to develop site-selective and size-specific atherosclerotic lesions over time. The current study should provide information on diet induction or drug intervention times and facilitate estimation of the appropriate locations of atherosclerotic lesions in Ldlr −/− mice.
With abundant crystal defects, cerium oxide (CeO2), widely used in heterogeneous catalysis, has attracted extensive attention. In recent years, researchers have investigated that the defect chemistry of CeO2 plays a vital role in its catalytic activity and have developed various defect introduction methods to synthesize stable and efficient defective CeO2‐based catalysts. Herein, the understanding, introduction, and applications of defect chemistry in CeO2‐based heterogeneous catalysis are reviewed, and the structure–activity relationship between defect engineering and catalytic performance is recommended with great emphasis. Interests are put into the investigation of how defects influence the activity and stability of defective CeO2 catalysts and effective strategies for fabricating efficient, stable, and defective CeO2 catalysts. Finally, the existing problems and perspectives of CeO2 defect chemistry for heterogeneous catalysis are displayed. This review provides a reference for in‐depth understanding and the design of more efficient CeO2‐based catalysts for heterogeneous catalysis.
5-Hydroxymethylfurfural oxidation reaction (HMFOR) is regarded as a promising approach to attain biomassderived high-value chemical products. As the HMFOR process is complicated, and the two-step oxidation of the aldehyde group and hydroxyl group in 5-hydroxymethylfurfural (HMF) is typically involved, it is fundamentally significant to understand the different catalytic processes for HMFOR. In this work, we identify direct and synergistic oxidation types for HMFOR on cobalt oxide catalysts. For the direct HMFOR process, Co 3 O 4 was found to have a higher activity for the aldehyde group than for the hydroxyl group due to the higher reaction barrier of hydration in the hydroxyl oxidation. By studying the hydroxyl oxidation behaviors in transition metal oxides, NiO exhibited optimal hydroxyl activity owing to the appropriate OH adsorption energy for alcohol dehydrogenation. Therefore, the optimal HMFOR performance was achieved by accurately introducing Ni into the tetrahedral catalytic sites of cobalt spinel oxides to improve the hydroxyl activity. The integrated catalytic sites enhanced the overall activity of HMFOR with 92.42% FDCA yield and 90.35% faradaic efficiency. This work provides a promising perspective for designing efficient electrocatalysts for HMFOR.
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