Current Issue

2024, Volume 9,  Issue 10

Display Method:
Short communication
Abstract:
Machine learning combined with density functional theory (DFT) enables rapid exploration of catalyst descriptors space such as adsorption energy, facilitating rapid and effective catalyst screening. However, there is still a lack of models for predicting adsorption energies on oxides, due to the complexity of elemental species and the ambiguous coordination environment. This work proposes an active learning workflow (LeNN) founded on local electronic transfer features (e) and the principle of coordinate rotation invariance. By accurately characterizing the electron transfer to adsorption site atoms and their surrounding geometric structures, LeNN mitigates abrupt feature changes due to different element types and clarifies coordination environments. As a result, it enables the prediction of *H adsorption energy on binary oxide surfaces with a mean absolute error (MAE) below 0.18 eV. Moreover, we incorporate local coverage (θl) and leverage neutral network ensemble to establish an active learning workflow, attaining a prediction MAE below 0.2 eV for 5419 multi-*H adsorption structures. These findings validate the universality and capability of the proposed features in predicting *H adsorption energy on binary oxide surfaces.
Review articles
Abstract:
Electricity-driven water splitting to produce hydrogen is one of the most efficient ways to alleviate energy crisis and environmental pollution problems, in which the anodic oxygen evolution reaction (OER) is the key half-reaction of performance-limiting in water splitting. Given the complicated reaction process and surface reconstruction of the involved catalysts under actual working conditions, unraveling the real active sites, probing multiple reaction intermediates and clarifying catalytic pathways through in-situ characterization techniques and theoretical calculations are essential. In this review, we summarize the recent advancements in understanding the catalytic process, unlocking the water oxidation active phase and elucidating catalytic mechanism of water oxidation by various in-situ characterization techniques. Firstly, we introduce conventionally proposed traditional catalytic mechanisms and novel evolutionary mechanisms of OER, and highlight the significance of optimal catalytic pathways and intrinsic stability. Next, we provide a comprehensive overview of the fundamental working principles, different detection modes, applicable scenarios, and limitations associated with the in-situ characterization techniques. Further, we exemplified the in-situ studies and discussed phase transition detection, visualization of speciation evolution, electronic structure tracking, observation of reaction active intermediates, and monitoring of catalytic products, as well as establishing catalytic structure-activity relationships and catalytic mechanism. Finally, the key challenges and future perspectives for demystifying the water oxidation process are briefly proposed.
Abstract:
In recent years, porous organic catalysts have been developed and become research hotspots in photo/electrocatalysis due to their inherent pores, high specific surface area, chemical and thermal stability, and diverse functional building blocks. Phenazine-linked organic catalysts, exhibited excellent conjugation, electrical conductivity, chemical, and thermal stability, could bring in N atoms with specific numbers and positions to regulate electron levels, anchor metals, and absorb near-infrared light, which expands solar energy utilization. These advantages of the phenazine-linked catalysts attracted our group and numerous researchers to conduct experimental and computational work on photo/electrocatalytic applications and mechanisms. This review summarizes the recent significant research progress, synthesis methods, photo/electrocatalytic performance, and applications of relative phenazine-linked catalysts. Furthermore, the photo/electrocatalytic mechanism was systematized and summarized by combining experiments and density functional theory calculations simultaneously.
Abstract:
The climate crisis necessitates the development of non-fossil energy sources. Harnessing solar energy for fuel production shows promise and offers the potential to utilize existing energy infrastructure. However, solar fuel production is in its early stages of development, constrained by low conversion efficiency and challenges in scaling up production. Concentrated solar energy (CSE) technology has matured alongside the rapid growth of solar thermal power plants. This review provides an overview of current CSE methods and solar fuel production, analyzes their integration compatibility, and delves into the theoretical mechanisms by which CSE impacts solar energy conversion efficiency and product selectivity in the context of photo-electrochemistry, thermochemistry, and photo-thermal co-catalysis for solar fuel production. The review also summarizes approaches to studying the photoelectric and photothermal effects of CSE. Lastly, it explores emerging novel CSE technology methods in the field of solar fuel production.
Research papers
Abstract:
The development of passive NOx adsorbers with cost-benefit and high NOx storage capacity remains an on-going challenge to after-treatment technologies at lower temperatures associated with cold-start NOx emissions. Herein, Cs1Mg3Al catalyst prepared by sol-gel method was cyclic tested in NOx storage under 5 vol% water. At 100 ℃, the NOx storage capacity (1219 μmol g-1) was much higher than that of Pt/BaO/Al2O3 (610 μmol g-1). This provided new insights for non-noble metal catalysts in low-temperature passive NOx adsorption. The addition of Cs improved the mobility of oxygen species and thus improved the NOx storage capacity. The XRD, XPS, IR spectra and in situ DRIFTs with NH3 probe showed an interaction between CsOx and AlOx sites via oxygen species formed on Cs1Mg3Al catalyst. The improved mobility of oxygen species inferred from O2-TPD was consistent with high NOx storage capacity related to enhanced formation of nitrate and additional nitrite species by NOx oxidation. Moreover, the addition of Mg might improve the stability of Cs1Mg3Al by stabilizing surface active oxygen species in cyclic experiments.
Abstract:
Lithium hexafluorophosphate (LiPF6), the most commonly used lithium battery electrolyte salt, is vulnerable to heat and humidity. Quantitative and qualitative determination the variation of LiPF6 have always relied on advanced equipment. Herein, we develop a fast, convenient, high-selective fluorescence detection method based on metal-organic cages (MOC), whose emission is enhanced by nearly 20 times in the presence of LiPF6 with good stability and photobleaching resistance. The fluorescent probe can also detect moisture in battery electrolyte. We propose and verify that the luminescence enhancement is due to the presence of hydrogen bond-induced enhanced emission effect in cages. Fluorescent excitation-emission matrix spectra and variable-temperature nuclear magnetic resonance spectroscopy are employed to clarify the role of hydrogen bonds in guest-loaded cages. Density functional theory (DFT) calculation is applied to simulate the structure of host-guest complexes and estimate the adsorption energy involved in the system. The precisely matched lock-and-key model paves a new way for designing and fabricating novel host structures, enabling specific recognition of other target compounds.
Abstract:
Li metal batteries (LMBs) with LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes could release a specific energy of >500 Wh kg-1 by increasing the charge voltage. However, high-nickel cathodes working at high voltages accelerate degradations in bulk and at interfaces, thus significantly degrading the cycling lifespan and decreasing the specific capacity. Here, we rationally design an all-fluorinated electrolyte with addictive tri(2,2,2-trifluoroethyl) borate (TFEB), based on 3, 3, 3-fluoroethylmethylcarbonate (FEMC) and fluoroethylene carbonate (FEC), which enables stable cycling of high nickel cathode (LiNi0.8Co0.1Mn0.1O2, NMC811) under a cut-off voltage of 4.7 V in Li metal batteries. The electrolyte not only shows the fire-extinguishing properties, but also inhibits the transition metal dissolution, the gas production, side reactions on the cathode side. Therefore, the NMC811||Li cell demonstrates excellent performance by using limited Li and high-loading cathode, delivering a specific capacity > 220 mA h g-1, an average Coulombic efficiency > 99.6% and capacity retention > 99.7% over 100 cycles.
Abstract:
The serious environmental threat caused by petroleum-based plastics has spurred more researches in developing substitutes from renewable sources. Starch is desirable for fabricating bioplastic due to its abundance and renewable nature. However, limitations such as brittleness, hydrophilicity, and thermal properties restrict its widespread application. To overcome these issues, covalent adaptable network was constructed to fabricate a fully bio-based starch plastic with multiple advantages via Schiff base reactions. This strategy endowed starch plastic with excellent thermal processability, as evidenced by a low glass transition temperature (Tg= 20.15 ℃). Through introducing Priamine with long carbon chains, the starch plastic demonstrated superior flexibility (elongation at break = 45.2%) and waterproof capability (water contact angle = 109.2°). Besides, it possessed a good thermal stability and self-adaptability, as well as solvent resistance and chemical degradability. This work provides a promising method to fabricate fully bio-based plastics as alternative to petroleum-based plastics.
Abstract:
Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion, facile separation, and environmental friendliness. However, their widespread applications are impeded by basic components aggregation and low stability. In this work, we fabricate single calcium atoms on graphene (denoted as Ca1/G) by use of a redox strategy for the first time, producing solid strong base catalyst with high activity and stability. The precursor Ca(NO3)2 is first reduced to CaO at 400 ℃ by the support graphene, forming CaO/G with conventional basic sites, and the subsequent reduction at 850 ℃ results in the generation of Ca1/G with atomically dispersed Ca. Various characterizations reveal that Ca single atoms are anchored on graphene in tetra-coordination (Ca-C2-N2) where N is in situ doped from Ca(NO3)2. The atomically dispersed Ca, along with their anchoring on the support, endow Ca1/G with high activity and stability toward the transesterification reaction of ethylene carbonate with methanol. The turnover frequency value reaches 128.0 h-1 on Ca1/G, which is much higher than the traditional counterpart CaO/G and various reported solid strong bases (2.9-46.2 h-1). Moreover, the activity of Ca1/G is well maintained during 5 cycles, while 60% of activity is lost for the conventional analogue CaO/G due to the leaching of Ca.
Abstract:
Plastic waste is an underutilized resource that has the potential to be transformed into value-added materials. However, its chemical diversity leads to cost-intensive sorting techniques, limiting recycling and upcycling opportunities. Herein, we report an open-loop recycling method to produce graded feedstock from mixed polyolefins waste, which makes up 60% of total plastic waste. The method uses heat flow scanning to quantify the composition of plastic waste and resolves its compatibility through controlled dissolution. The resulting feedstock is then used to synthesize blended pellets, porous sorbents, and superhydrophobic coatings via thermally induced phase separation and spin-casting. The hybrid approach broadens the opportunities for reusing plastic waste, which is a step towards creating a more circular economy and better waste management practices.