Air pollution is a major challenge for the improvement of urban environmental quality. The process of urbanization is an important cause of highly complex air pollution. On the other hand, it also provides artificial reinforcement conditions for self-purification of air pollutants in cities. “Environmental catalytic city” refers to the spontaneous catalytic purification of low-concentration gaseous pollutants in the atmosphere by catalytic materials coating on artificial surfaces, such as building surfaces in the city, under natural photothermal conditions. “Environmental catalytic city” is of great significance for the control of complex air pollution without additional energy consumption, the continuous improvement of indoor and outdoor air quality, and the scheme and construction of a “self-purifying city”. Here, we propose the concept of an “environmental catalytic city”, and discuss its further improvement, development, and application.

Theoretical design of fuel has always been the focus of research about fuel in the area of propulsion technology. It can effectively overcome the complexity and potential danger of the experiment, and guide experimental synthesis of fuel, which can be verified by experimental results. It is anticipated that a new generation of fuel can be efficiently designed for subsequent fuel synthesis and application. However, the traditional theoretical calculation methods, such as group contribution method and quantum chemical method, have the defects of low accuracy and efficiency. Machine learning, a rapidly developed algorithm, has opened up a new way to design potential high-energy fuels, which exhibits strong capabilities in both property prediction and molecule design. In this review, several fuel molecule descriptors for machine learning are introduced, and different machine learning models for fuel property prediction and molecule design are briefed. Furthermore, the research on machine learning assisted property prediction and new molecule design of fuel is summarized, respectively. Finally, the challenges and future development of machine learning applied in fuel design are discussed.

In order to alleviate the environmental pollution and energy crisis caused by petroleum-based plastics, biodegradable plastics are gradually becoming the focus and hot spot of the development of the plastics industry. Plant resources include a variety of available components, such as lignin, cellulose, vegetable oil, terpenes, etc. These natural polymers or small molecules can be used to prepare bioplastics, with the advantages of renewable, non-toxic, completely degradable and so on. This review includes two types of direct and indirect utilization (including chemical modification, biochemical modification and microbial fermentation) for plant resources, and focuses on the recent progress of eight plant components (cellulose, lignin, hemicellilose, starch, plant protein, vegetable oil, terpenes and tannins) in the field of bioplastics, and discusses in detail application characteristics of these natural plant components. Finally, the trend in future is also proposed.

Biocatalysis has become an important technology in the field of biosynthesis because of its mild reaction conditions, high efficiency, high specificity and low price. There are a series of highly integrated metabolic networks in the biosynthesis system, and the study of multi-enzyme catalytic system has become an inevitable trend in the field of biosynthesis, so it is of great significance to explore the unknown multi-enzyme synthesis path based on the known products. In this review, the concepts of multi-enzyme system and retrosynthesis process are introduced. And the design methods, advantages and disadvantages of retrosynthesis tools are summarized. Then the tools are divided into host-based and host-less tools. For each of these two types, some representative retrosynthesis tools are listed to analyze their respective design processes and differences. Finally, the possibility of artificial intelligence-assisted multi-enzyme system is discussed and the optimization and development of multi-enzyme pathway construction tools are forecasted.

With the rapid development of society and economy, the demand for energy has been continuously increasing. Solar energy has emerged as a clean energy source with great development potential, and the long-term effective utilization of solar energy has become an urgent problem that needs to be addressed. Metal-organic frameworks (MOFs) derived metal sulfides retain the original structural characteristics of their parent MOFs, including large surface areas, dispersed nanoscale subunits, and abundant active sites. They overcome the limitations of MOFs in terms of material stability at high temperatures and harsh chemical environments. Moreover, compared to metal oxides, they have a narrower bandgap, which extends their light absorption range to the visible region. The porous nature of MOFs-derived metal sulfides also provides additional pathways for light-induced electron migration, promoting charge carrier separation. As a result, they have attracted increasing attention in the field of photocatalysis. Although this field is still in its nascent stage, the results obtained so far indicate that MOF-derived metal sulfides and their composite photocatalysts have high potential for practical applications. This article systematically elucidates the synthesis, performance, and mechanisms of MOFs-derived metal sulfide photocatalysts and their composites in various application areas, such as wastewater treatment, water splitting for hydrogen generation, and CO₂ reduction. This will provide a new direction for the synthesis and application of novel and efficient composite photocatalytic materials. Additionally, some existing issues in current research are addressed, and the future prospects and challenges of MOFs-derived sulfide photocatalytic materials are discussed.

Zeolites as one kind of important porous materials have a wide range of applications in the fields of adsorption, ion exchange, and catalysis due to their special pore structure, suitable acidity, and high hydrothermal stability. The classical hydrothermal route of synthesizing zeolites suffers from low zeolite yields, high synthesis costs, and serious pollution. Coupling the classical synthesis routes of zeolites with those recently developed new non-conventional routes is an important way to solve the above problems and achieve technological innovation in zeolite synthesis. To this end, this review firstly introduces the principles and characteristics of those non-conventional synthesis routes of zeolites, then briefly introduces the concepts of coupling synthesis routes of zeolites, and then focuses on the latest progress in the preparation of zeolites by microwave synthesis, solvent-free synthesis, and seed-directed synthesis coupled with other routes. Finally, the main problems existing in these coupling routes are analyzed and viewed.

Low-symmetry two-dimensional materials are a new type of nanomaterials with few lattice symmetry operations and only atomic-level thickness in the longitudinal direction. In the two-dimensional transition metal dichalcogenides (TMDs) system, 1T'-MoTe₂, 1T'-WTe₂, 1T'-ReS₂ and 1T'-ReSe₂ are typical low-symmetry members. The unique lattice symmetry brings them rich anisotropic physical and chemical properties, so they have special application prospects in the fields of micro-nano photonics, tactile sensors, and anisotropic logic devices. The basic research and application development of low-symmetry two-dimensional TMD materials relies on the high-quality, large-size, and stable preparation of such materials. Therefore, this paper takes these four types of materials as typical materials, first classifies them according to metal precursors, and reviews the chemical vapor deposition (CVD) preparation methods of low-symmetry two-dimensional TMD materials in recent years. According to the characteristics of 1T′-MoTe₂ easy to undergo phase transition and weak interaction between 1T'-ReS₂, 1T'-ReSe₂ and the substrate during the preparation process, the phase regulation mechanism in the preparation process of 1T'-MoTe₂ and the substrate engineering research in the preparation process of 1T'-ReS₂ and 1T'-ReSe₂ were introduced. Finally, this paper looks forward to the future challenges and opportunities of low-symmetry 2D TMDs materials.

With the rapid development of radio waves and electronic information technology, the problem of electromagnetic radiation pollution is becoming more and more prominent, which has attracted wide attention around the world. In order to solve the problem of electromagnetic pollution, people are committed to researching and developing electromagnetic wave-absorbing materials with light weight, thin thickness, a wide frequency band, and strong absorption. Compared with traditional wave-absorbing materials, carbon-based composite wave-absorbing materials have excellent dielectric properties, special microstructure, good impedance matching and efficient wave-absorbing properties, and can effectively reduce the mass of composite materials, which has great development potential in the field of wave-absorbing materials, and has gradually become a research hotspot. In this paper, the basic absorption principle of electromagnetic wave is summarized from the aspects of impedance matching and loss mechanism, and the research progress of carbon-carbon, carbon-metal/metal oxide, carbon-ceramics and other kinds of carbon-based composite absorbing materials is reviewed. At the same time, the synthesis methods, absorption properties and attenuation mechanism of these carbon-based composite absorbing materials are reviewed. Finally, the shortcomings of carbon-based composite absorbing materials in electromagnetic wave absorption are discussed and possible solutions are put forward, and the future development direction of carbon-based composite absorbing materials is prospected.

The massive consumption of fossil fuels has caused the continuous increase of carbon dioxide concentration in the atmosphere, resulting in serious climate and environmental problems such as greenhouse effect and sea level rise. The use of solar photocatalysis to reduce CO₂ to hydrocarbon fuel with added value is regarded as one of the most promising potential solutions. Researchers have developed a variety of photocatalysts, among which carbon dots are a new type of carbon nanomaterials with a size of less than 10 nm. They have unique up-conversion luminescence properties and can promote electron transfer. The synthesis method is friendly and safe. They are widely used in the field of photocatalytic reduction of CO₂. In this paper, starting from the mechanism of photocatalytic reduction of CO₂, the action mechanism and performance evaluation of carbon dots and carbon dot composite materials in photocatalytic reduction of CO₂ are reviewed in detail in terms of light absorption efficiency, carrier separation efficiency, CO₂ adsorption capacity and multiple interactions. The advantages of carbon dots in the field of photocatalytic reduction of CO₂ are summarized. The existing challenges and possible ways to address the challenges in the future are analyzed. And the future development is prospected. It provides a new idea for promoting the development of carbon dot-based photocatalysts.

Lignocellulose aerogels possess excellent properties of low density, high porosity, low thermal conductivity and so on, making them widely utilized in thermal insulation, adsorption, catalysis, electromagnetic shielding, biomedical and other fields. Moreover, as a bio-based material, lignocellulose is a green, pollution-free, renewable, and sustainable material. In this paper, the latest research progress of wood-based cellulose and agricultural waste-based cellulose aerogels are reviewed. Then the current research status of lignocellulose aerogel preparation methods including freeze-drying, supercritical drying, and atmospheric drying, is summarized. In addition, for the flammability issues commonly found in lignocellulose aerogels, commonly used methods to improve the flame retardancy of lignocellulose aerogels are discussed in detail. Finally, this paper concludes the main problems in lignocellulose aerogel preparation methods and properties, and the future development direction in this field is proposed.

In recent years, there has been a significant surge of interest in exploring exhaled gas detection within the context of diabetes research. This burgeoning field has attracted considerable attention due to its potential implications for the early detection and management of diabetes mellitus. Through a comprehensive synthesis of 114 pertinent scholarly works, researchers have delved into the intricate association between diabetes mellitus and exhaled gas detection. Leveraging state-of-the-art detection and analysis methodologies, including gas chromatography, mass spectrometry, spectroscopy, and sensor-based detection systems. This review provides an overview of the composition of some volatile organic compounds and their sources in the exhaled gas of diabetic patients. Furthermore, the application of machine learning-based algorithms has been scrutinized for its potential to facilitate predictive modeling of diabetes risk and associated complications. This comprehensive review also examines the national and international landscape of the development and application of exhaled gas detection methodologies in diabetes research, offering critical insights into current limitations and potential avenues for future research and application.