查看更多>>摘要：Inspired by the concept of frustrated Lewis pairs (FLPs) from homogeneous catalysis, an organic supramolecular bridged metal-organic frameworks (MOFs) heterojunction, i.e., a perylene-3,4,9,10-tetracarboxylic diimide@MIL-125(Ti)-NH2 (denoted PDI@MTi) composite is successfully fabricated via a two-step synthesis method. Experimental characterisations and theoretical calculations reveal that in the obtained 'TiO_(5-x)-ligand-PDI" FLPs, the unsaturated Ti-Oclusters function as a Lewis acid to accept photogenerated electrons, and the PDI sites act as a Lewis base to capture photogenerated holes. With the unique structure characteristics, the PDI@MTi shows excellent photocatalytic activity toward the disinfection of Staphylococcus aureus and Cr(VI) reduction, with 1.0- and 10.3-fold enhancements, respectively, compared with unadorned MTi. The synergic effects of the micro polarisation field, multiple active sites, and a C-N bonded interface contributed to photoactivity enhancement. This work demonstrates the potential of using MTi as a platform for constructing FLPs-containing heterogeneous photocatalysts and provides new strategies to control carrier separation.
查看更多>>摘要：Interface engineering is an effective strategy to regulate surface properties and improve the catalytic activities of materials. Here we develop an interface engineered core-shell structure FeP@CoP catalyst, which only requires 50 mV to realize current density of 10 mA/cm~2 with a lowTafel slope of 51.1 mV/dec in 1 M KOH. Density functional theory (DFT) simulations indicate the FeP@CoP interface exhibits optimal H* adsorption energy (0.06 eV) compared with pure-phased CoP (0.26 eV) and pure-phased FeP (-0.18 eV), which is attributed to the significantly electronic structure modulation of Fe and Co atoms at the interface domain. Furthermore, the assembled NiFe LDH@Co3O4/NF||FeP@CoP/NF electrolyzer only demands the voltages of 1.50 and 1.70 V to achieve 10 and 100 mA/cm~2 under 1 M KOH. The electrolyzer also exhibits considerable catalytic performance in alkaline seawater electrolyte. What's more, it also can be driven by a commercial Si solar panel under AM 1.5 G100 mW/cm~2 illumination. The regulation of interface-effect paves a novel avenue for constructing high-performance catalysts for hydrogen production.
查看更多>>摘要：CO2 methanation is gaining renewed attention due to the emerging application needs such as the power-to-gas concept and long-term space exploration missions. Maximizing the amounts of interfacial sites generally regarded as the efficient active sites is considered to be one of the most direct means to enhance catalytic activity but few breakthroughs have been made. Here, Eu~(3+) is introduced to Ni/CeO2 to promote the Ni-CeO2 interaction, resulting in a remarkable low-temperature CO2 methanation activity. Structural characterization indicates that the Ni/CeEu(9:l) catalyst achieves higher Ni dispersion compared to Ni/CeO2, which consequently generates more interfacial sites. More interfacial sites enhance the proportions of bidentate carbonates closer to interfacial sites as a faster hydrogenated species during the catalytic process, leading to enhanced low-temperature CO2 methanation activity over the Ni/CeEu(9:1) catalyst. This work provides a chemical strategy to enhance the amounts of active sites and bring insights into the origin of enhanced catalytic performance.
查看更多>>摘要：Novel alumina-supported Ni-Mo hydro desulfurization (HDS) catalysts were prepared via assembly of Mo and Al precursors induced by tetradecylamine (TDA). Compared with conventional impregnation, this assembly method improves Mo dispersion, weakens metal-support interactions, enhances Ni modification at MoS2 edge sites, and produces more NiMoS phases on Al2O3. The optimal NiMoS microstructure was obtained by modulating the TDA/Mo ratio in the assembly. A microstructure-activitv correlation indicated that the S vacancies at the NiMoS corner sites favored σ-adsorption and direct desulfurization of 4,6-dimethylbenzothiophene (4,6-DMDBT), and those at the NiMoS edge sites promoted C-S breaking in hydrogenated derivatives of 4,6-DMDBT. Among these catalysts, NiTMo-2.0/Al2O3, which had the most corner and edge S vacancies, exhibited the highest reaction rate constant of 5.89 × 10~(-7) mol·g~(-1)·s~(-1) and the highest desulfurization ratio of 99.5% in HDS of 4,6-DMDBT.
查看更多>>摘要：A kinetic model for formic acid (FA) decomposition over a commercial 10 wt% Pd/AC catalyst has been developed to describe the hydrogen production and to understand the deactivation mechanism. The kinetic data were obtained in a batch slurry reactor in absence of mass transfer limitation at: C_(FA,0) = 0.25-2 M, C_(CAT) = 1 g L~(-1), T = 25-85 °C and P = 1 atm. The catalyst stability was studied in successive cycles at different temperatures. Fresh, used and regenerated Pd/AC catalysts were deeply characterized to gain insight into the activity, selectivity and stability. H2 and CO2 were the only reaction products detected. The reaction follows a first order kinetic for FA while the activity shows exponential decay with the initial FA concentration and reaction temperature. This paper represents a step forward in the on-site hydrogen production technology by using FA as liquid organic hydrogen carrier.
Daniel Olivo-AlanfsAlcione Garcia-GonzalezMiguel Angel Mueses
12页
查看更多>>摘要：A novel generalized kinetic model was developed to predict the photocatalytic degradation of methylene blue and synthetic blue wastewater. The kinetic model was validated using nitrogen-crosslinking, ZnO-incorporated, and chlorophyll-sensitized phenolic resins as photocatalysts. The model considers the generation of reactive oxygen species (ROS), rate of electron-hole pair generation (Rg), and the attack of ROS on the pollutant. The six-flux model was used to elucidate the absorption and scattering of photons in a visible-LED tubular reactor, while the extended effective quantum yield model helped to calculate the harnessed energy by the photocatalyst;; both parameters were employed for the calculation of Rg. The model showed robustness and high accuracy (R~2 >0.85) under several operational conditions for dye-containing water. When the physical-chemical characteristics of the semiconductor and the reactive media are added to the kinetic model, it represents a major step in the process engineering of heterogeneous photocatalysis systems.
查看更多>>摘要：Dry reforming of methane (DRM) on Ni-based catalysts provides an economically and environmentally pivotal route to generate synthesis gas. However, coke formation on Ni surface bv the growth of carbon atoms is the main reason for catalyst deactivation and reactor blockage. Here, we propose a reaction-induced method to incorporate and store active carbon atoms into nickel octahedral sites in core-shell Ni3ZnC_(0.7)/Al2O3. This strategy can fundamentally avoid C-C bond formation and feasible oxidation of Ni3ZnC_(0.7) in low-temperature DRM under CO2-rich condition. About 2 nm of thin-layer Al2O3 encapsulated Ni3ZnC_(0.7) is explored as the carbon reservoir to accommodate sufficient interstitial carbon atoms, and less than 5% Ni3Zn was observed under CH4/CO2 < 1/1 for 100 h. The dynamic balance of carbon atom storage and conversion in robust Ni3ZnC_(0.7) contributes to the enhanced activity, stability, coke and oxidation resistance, and distinct reaction pathway in low-temperature DRM.
查看更多>>摘要：Efficient and stable electrocatalysts are essential for electrochemical denitrification of nitrate contamination in water. Herein, a cost-effective Cu2O/Cu NRs/CF cathode bearing abundant Cu active sites and electron-rich Cu2O sites with good atomic H* provision performance is reported to exhibit rapid nitrate reduction kinetics (0.04815 min~(-1)) and no nitrite accumulation. Benefiting from the enhanced mass transfer and sufficient H* provision, the rapid adsorption of *NO3, fast reduction of *NO2 to *NO, and highly selective *NO to *NOH transformation played critical roles in the electrochemical nitrate reduction process. Although ammonia was the main final nitrate reduction product, the electrocatalytic system we designed could effectively oxidize ammonia into N2 with the assistance of simultaneous electrochlorination, finally achieving 96.81% of N2 selectivity. Significantly, the long-term stability and low energy consumption to treat actual nitrate-contaminated wastewater make the Cu2O/Cu NRs/CF electrode promising for practical applications.
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