In this work, a QM/MM-based EDA method, called GKS-EDA(QM/MM), is proposed. As an extension of GKS-EDA, this scheme divides the total interaction energy into electrostatic, exchange-repulsion, polarization, and correlation/dispersion terms. GKS-EDA(QM/MM) can be applied to describe the interactions of large-scale systems combined with various QM/MM platforms. By using the examples of a hydrated hydronium ion complex in water solution, the barnase-barstar complex, and MMP-13-pyrimidinetrione in a metalloprotein, the capability of GKS-EDA(QM/MM) for various interactions in large systems is validated.
In this work, a QM/MM-based EDA method, called GKS-EDA(QM/MM), is proposed. As an extension of GKS-EDA, this scheme divides the total interaction energy into electrostatic, exchange-repulsion, polarization, and correlation/dispersion terms. GKS-EDA(QM/MM) can be applied to describe the interactions of large-scale systems combined with various QM/MM platforms. By using the examples of a hydrated hydronium ion complex in water solution, the barnase-barstar complex, and MMP-13-pyrimidinetrione in a metalloprotein, the capability of GKS-EDA(QM/MM) for various interactions in large systems is validated.
In the work, a real-space energy decomposition analysis method, called DM-EDA(RS), is introduced based on our recently developed DM-EDA method [Zhang et al., J. Chem. Phys. 160, 174101 (2024)]. The EDA terms in DM-EDA(RS), including electrostatic, exchange, repulsion, polarization, and correlation, are expressed as the summations of grid-based energy density in real-space. This method is able to interpret intermolecular interactions in a unified qualitative and quantitative way. DM-EDA(RS) results provide not only comprehensive explanations for intermolecular interactions but also insights for sub-region interactions involving different functional groups.
Three bis-anthracene (BA) compounds, characterized by varying alkyl chain lengths between the two anthracene groups, were synthesized and investigated using He-3 NMR spectroscopy on He@C-60 derivatives. The Diels-Alder reaction of these BAs with fullerene was comprehensively explored. Findings disclosed that BAs with shorter linkers formed mono-adducts with He-3@C-60 at lower concentrations. Conversely, the BA compound with the longest linker (1 c) yielded both mono-adducts and bis-para-adducts with C-60, marked by a distinct He-3 NMR signal peak for bis-adducts at -12.84 ppm. Importantly, the versatility of the He-3@C-60 probe was exemplified in characterizing intricate fullerene reactions that conventionally pose challenges. Theoretical analyses validated reaction products, with computational models substantiating experimental results.
Catalytic transformation of CO2 into chemicals in large demand such as ethanol has attracted much research attention under the background of establishing carbon-neutral societies. Supported Rh catalysts are promising candidates for the hydrogenation of CO2 to ethanol but suffer from low ethanol productivity and poor catalyst stability. Here, we report that zeolite silicalite-1 embedded Na-promoted Rh nanoparticles (Na-Rh@S-1) demonstrate high productivity and stability for CO2 hydrogenation to ethanol. The ethanol selectivity of 24% was attained at a CO2 conversion of 10%, and the space-time yield of ethanol reached 72 mmol g(Rh)(-1) h(-1), which outperformed most of the Rh-based catalysts reported to date. While a reference catalyst prepared by impregnation underwent deactivation, the Na-Rh@S-1 catalyst was stable for at least for 100 h owing to the confinement effect. The Na+ modifier played crucial roles in enhancing the CO2 conversion and ethanol selectivity by suppressing methane formation. The characterizations suggest that the presence of Na+ enables the coexistence of Rh-0 and Rh+ and enhances CO2 adsorption, thus boosting ethanol formation. A comparative study between CO and CO2 hydrogenation reveals that the Na-Rh@S-1 catalyst is significantly more active and selective toward CO2 hydrogenation to ethanol.
Recent studies demonstrate that bifunctional catalysts composed of metal oxide and zeolite can effectively control the hydrocarbon distribution in syngas conversion. In this effort, a set of eight silicoaluminophosphate (SAPO) zeolites with different topology structures are synthesized and integrated with a binary ZnAlO oxide for syngas conversion. The effects of micropore window size and cage size of SAPO zeolites, and reaction conditions on the hydrocarbon distribution are preliminarily investigated. It was found that the hydrocarbon distribution is primarily determined by the window size of SAPO zeolites, and a volcano trend was observed between the chain length of hydrocarbon products and the window sizes. The cage size of zeolites and reaction conditions only modifies the hydrocarbon distribution in a narrow range of chain length. The effect of zeolite topology on the hydrocarbon distribution in syngas conversion is overall in line with that in methanol conversion. These findings provide an efficient strategy to increase the selectivity of an individual hydrocarbon product in syngas conversion, such as ethylene, propylene, butenes, iso-butane and C5-C11 iso-paraffins.
合成气(CO和H2混合气)选择性制备碳氢化合物燃料及化学品是目前最具挑战的催化反应之一.我国拥有丰富的煤炭资源,发展煤经合成气催化转化技术可以减少对石油的依赖,因此相关研究具有十分重要的意义.近年来纳米反应器在合成气选择性转化反应中得到了广泛应用,其优势主要体现在孔道结构可控、表面可功能化、稳定活性金属、反应过程强化等方面.本文基于合成气选择性转化,重点介绍了纳米反应器的构筑以及调控碳氢化合物选择性方面的微观机制的研究进展,为合成气的选择性转化提供研究思路.
Maximizing the use of palladium without compromises in catalytic activity and stability in the combustion of methane is extremely challenging due to the harsh operation conditions. To achieve this goal, a series of core-shell-structured catalysts with different amounts of palladium nanoparticles confined in hydrophobic silicalite-1 (Pd@S-1) was designed. Unexpectedly, a volcanic trend between catalytic activity and palladium loading was found as the loading increased from 0.3 wt% to 1.6 wt%, among which the 0.6 wt%Pd@S-1 exhibited the highest catalytic activity with a complete combustion temperature of 380 degrees C. Besides, the 0.6 wt%Pd@S-1 showed an ultrahigh stability in the high temperature applications due to the spatial confinement of palladium inside the rigid zeolite matrix. Moreover, owing to the hydrophobicity of the pure silica zeolite, the Pd@S-1 could selectively hinder the diffusion of water vapor into the palladium sites, leading to the outstanding water-resistance ability.