In recent years, some experiments and theoretical work have pointed out that diatomic catalysts not only retain the advantages of monoatomic catalysts, but also introduce a variety of interactions, ...which exceed the theoretical limit of catalytic performance and can be applied to many catalytic fields. Here, the interaction between adjacent metal atoms in diatomic catalysts is elaborated: synergistic effect, spacing enhancement effect (geometric effect), and electronic effect. With regard to the classification and characterization of various new diatomic catalysts, diatomic catalysts are classified into four categories: heteronuclear/homonuclear, with/without carbon carriers, and their characterization measures are introduced and explained in detail. In the aspect of preparation of diatomic catalysts, the widely used atomic layer deposition method, metal–organic framework derivative method, and simple ball milling method are introduced, with emphasis on the formation mechanism of diatomic catalysts. Finally, the effective control strategies of four diatomic catalysts and the key applications of diatomic catalysts in electrocatalysis, photocatalysis, thermal catalysis, and other catalytic fields are given.
The interaction between adjacent metal atoms (synergistic effect, geometric effect, and electronic effect), synthetic techniques, and prospective strategies and diversified catalysis applications (including thermocatalysis, photocatalysis, and electrocatalysis) of diatomic catalysts are elaborated and systematically summarized.
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The concept of “single‐atom catalysis” is first proposed by Tao Zhang, Jun Li, and Jingyue Liu in 2011. Single‐atom catalysts (SACs) have a very high catalytic activity and greatly improved atom ...utilization ratio. At present, SACs have become frontier materials in the field of catalysis. Aerogels are highly porous materials with extremely low density and extremely high porosity. These pores play a key role in determining their surface reactivity and mechanical stability. The alliance of SACs and aerogels can fully reflect their structural advantages and lead to new enhancement effects. Herein, a general concept of “atomic aerogel materials” (AAMs) (or single‐atom aerogels (SAAs)) is proposed to describe this interesting new paradigm in both material and catalysis fields. Based on the basic units of “gel,” the AAMs can be divided into two categories: carrier‐level AAMs (with micro‐, nano‐, or sub‐nanometer pore structures) and atomic‐level AAMs (with atomic‐defective or oxygen‐bridged sub‐nanopore structures). The basic unit of the former (i.e., single‐atom‐functionalized aerogels) is the carrier materials in nanostructures, and the latter (i.e., single‐atom‐built aerogels) is the single metal atoms in atomic structures. The atomic‐defective or oxygen‐bridged AAMs will be important development directions in versatile heterogeneous catalytic or noncatalytic fields. The design proposals, latent challenges, and coping strategies of this new “atomic nanosystem” in applications are pointed out as well.
A new concept of atomic aerogel materials (or single‐atom aerogels) is proposed for materials science and catalysis science; and their scientific significances, synthetic breakthrough, and potential applications are systematically summarized.
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Academician Tao Zhang from China and co‐workers designed the first Pt1/FeOx single‐atom catalysts (SACs) in 2011, and they proposed the concept of “single‐atom catalysis” in the field of ...heterogeneous catalysis. Generally, it is easy for active metal single‐atom sites on a carrier to migrate and aggregate, which results in poor performance; or the chemical bond between the metal atom and carrier is too strong (immovable), which results in passivation of the active site. Recently, “nano‐island” type SACs were designed, in which the active metal atoms are isolated on the “islands”, and can move within the respective “island”, but the migration across the “island” is blocked, to achieve a dynamic confinement design of single atoms (that is, a “moving but not aggregating” design philosophy). Herein, a new concept of “single‐atom nano‐islands (SANIs)” is proposed to describe these congeneric “atomic–nano” systems in heterogeneous catalysis fields. Particularly, the SANIs are divided into three categories: “one‐island–one‐atom”, “one‐island–multi‐atoms”, and “island–sea synergism” architectures. The scientific significance and application principles of SANIs in versatile heterogeneous catalysis fields (i.e., thermocatalysis, electrocatalysis, and photocatalysis) are summarized. The challenges and proposals of SANIs are also provided.
A new concept of single‐atom nano‐islands (SANIs) is proposed for materials science and catalysis science, and their synthetic breakthrough, scientific significances, and potential applications are systematically summarized.
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Due to the unique geometric characteristics and electronic structure of hierarchical 3D nanosheets, they show excellent electron migration rate, ultra‐high specific surface area, and reliable ...structural stability. Therefore, 3D nanosheets have great application prospects in the field of electrochemical energy storage. Supercapacitor has attracted extensive attention in recent years due to its merits of fast charge and discharge, long cycle life, safety, and stability. Flexibility, miniaturization, and intelligent integration are the development direction of supercapacitor energy storage devices. The emerging 3D printing technology, especially the ink direct writing mode, has greatly improved the design ability and control accuracy of device microstructures. Based on the research progress of 3D graphene nanosheets and 3D MXene nanosheets in the early stage of the authors’ or other teams, this paper proposes to use advanced 3D printing technology to realize the design of flexible all solid‐state supercapacitors by using 3D nanosheets active materials with high specific capacitance. The design methods of interdigital electrodes, multilayer skeleton electrodes and fiber electrodes by 3D printing technology and the performance evaluation of flexible supercapacitor are systematically analyzed. This perspective review aims to provide new conception and theoretical guidance for the design, preparation, and performance optimization of 3D nanosheets‐built materials by 3D printing for the practical application of flexible all‐solid‐state supercapacitor in the future.
New conception and theoretical guidance for the design high‐performance flexible all‐solid‐state supercapacitor are provided by summarizing the recent progress of 3D nanosheet active materials and 3D manufacturing (3D printing) technology.
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In 2011, Zhang's research team, in cooperation with Li and Liu, reported the Pt
1
/FeO
x
atomically dispersed catalysts for the first time in the world, and based on this, proposed the concept of ..."single-atom catalysts". Single-atom catalysts (SACs) have a wide range of industrial application prospects in the catalytic synthesis of fine chemicals due to their high atomic utilization rate and special catalytic activity. With the deepening of the research, the preparation methods of SACs emerge in an endless stream, but it is still an urgent problem to realize the industrial production of highly stable SACs prepared in small batches (gram level) or even in large batches (kilogram level). In this review paper, several typical solvent-free green synthetic strategies (
e.g.
, ball milling, physical mixing, gas migration, and pyrolyzing coordination polymers (including MOFs)) for the batch preparation of SACs are introduced. And typical catalytic application of SACs in green synthesis of fine chemicals by means of oxidation reaction, hydrogenation reaction, coupling reaction and other reactions are also introduced. This is the first review paper focusing on the mass preparation techniques of SACs and their applications in fine chemicals production.
The batch preparation technology and the thermo-catalysis application of SACs in fine chemical industries are highlighted.
This article presents an improved fractional-order active disturbance rejection control (iFO-ADRC) scheme to approximately render the open-loop transfer function of a high-order uncertain system to a ...weighed Bode's ideal transfer function (wBITF). The proposed feedback controller in this scheme is called iFO-ADRC-wBITF and abbreviated to iFO-BITF, which inherits the advantages of ADRC and wBITF and improves a system's robustness to open-loop gain variation and system uncertainty. As a core component of iFO-ADRC, an improved fractional-order extended state observer (iFO-ESO) can reduce the number of system states to be estimated and hence improve the performance of a closed-loop system. Frequency-domain analysis shows that iFO-ESO has better estimation performance than the typical FO-ESO in the literature. Compared with the conventional integer-order ADRC and the fractional-order controller for achieving BITF, the proposed iFO-BITF has a simpler form, better transient performance, and more robustness against parameter variation, as demonstrated in time-domain simulation. The proposed iFO-BITF is applied to a permanent magnet synchronous motor servo control system to demonstrate its capability in a real-world application.
This article introduces a method incorporating the gait and feedback controller design for a four-link biped robot. Inspired by the human gait and previous biped work, we propose a class of periodic ...gaits composed from the sum of sinusoidal harmonics up to the second order. This class of gaits, parameterized by design parameters, satisfies the impact model of the biped dynamics and enables us to design the step length and average walking velocity explicitly. The satisfaction of the impact model introduces constraints on design parameters, which together with the explicit parameterization significantly reduces the number of the design variables. Compared to the hybrid zero dynamics (HZD) method, the process of the gait design requires fewer parameters and shorter computation time, and thus, it can be conducted in real-time systems. The state-feedback controller is then proposed to ensure that the periodic gait is the limit cycle of the closed-loop system and its stability is theoretically guaranteed based on the Poincaré section method. Due to the explicit parameterization, the controller can be easily extended to achieve walking on different slopes with the same step length and average walking velocity. Finally, the theoretical result is verified by simulations for biped walking on different slopes with various gaits and controller parameters. The controller is found to be robust to external disturbance and model uncertainty.
Hollow carbon nanocages (HCNCs) consisting of sp2 carbon shells featured by a hollow interior cavity with defective microchannels (or customized mesopores) across the carbon shells, high specific ...surface area, and tunable electronic structure, are quilt different from the other nanocarbons such as carbon nanotubes and graphene. These structural and morphological characteristics make HCNCs a new platform for advanced electrochemical energy storage and conversion. This review focuses on the controllable preparation, structural regulation, and modification of HCNCs, as well as their electrochemical functions and applications as energy storage materials and electrocatalytic conversion materials. The metal single atoms‐functionalized structures and electrochemical properties of HCNCs are summarized systematically and deeply. The research challenges and trends are also envisaged for deepening and extending the study and application of this hollow carbon material. The development of multifunctional carbon‐based composite nanocages provides a new idea and method for improving the energy density, power density, and volume performance of electrochemical energy storage and conversion devices.
In this review, a clear and comprehensive definition of hollow carbon nanocages (HCNCs) is provided. The latest research progress (including preparation, regulation, and modification) of HCNCs in the field of electrochemical energy storages and conversions is detailly reviewed and discussed. The challenges and some insights into new trends and directions for HCNCs are also provided.
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Gastric cancer (GC) is the fifth most common type of cancer and the third leading cause of death due to cancer worldwide. The gastric mucosa often undergoes many years of precancerous lesions of ...gastric cancer (PLGC) stages before progressing to gastric malignancy. Unfortunately, there are no effective Western drugs for patients with PLGC. In recent years, traditional Chinese medicine (TCM) has been proven effective in treating PLGC. Classical TCM formulas and chemical components isolated from some Chinese herbal medicines have been administered to treat PLGC, and the main advantage is their comprehensive intervention with multiple approaches and multiple targets. In this review, we focus on recent studies using TCM treatment for PLGC, including clinical observations and experimental research, with a focus on targets and mechanisms of drugs. This review provides some ideas and a theoretical basis for applying TCM to treat PLGC and prevent GC.
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•This review summarized the mainly classification of syndrome differentiation of PLGC.•This review summarized the therapy of Chinese medicine formulas or components on PLGC.•This review listed the pharmacological mechanisms of the TCM for PLGC.
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Expressive art therapy, which originated from art therapy, uses visual art as a carrier and plays a complementary role in clinical medicine and psychological medicine in the healing process of ...mentally ill patients. With the rapid development of science and technology, expressive art therapy has also entered the field of technology-oriented virtual reality. This study aims to summarize the clinical psychology research of expressive art therapy based on virtual reality, to review the current state of the field, in order to provide detailed scientific research evidence summary for relevant content and complete knowledge reserve.
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