As an n-type wide band gap semiconductor material and high-performance energy material, SnO2 has special properties and structure and has been widely used in many aspects, such as transparent light electrode, electrocatalysis, photocatalysis, gas sensitive sensor, lithium ion battery, environmental catalysis, and so on. With the progress of science and technology and the development of economy, the controllable preparation and batch application of nano-SnO2 materials are within reach. In this chapter, the structural features, preparation methods, energy (solar cells, lithium-ion batteries, and electrocatalytic conversion) and environmental applications (adsorption purification and photocatalytic degradation), and typical case analysis of nano-MnO2 are briefly analyzed and summarized.
As a new kind of catalytic material, transition metal carbide has shown its unique catalytic performance. In recent years, researchers have paid special attention to this new kind of material. Tungsten carbides (such as WC and Co3W3C) have good stability in acidic environment and platinum-like electronic structures. They have been considered as potential replacement catalysts for benchmark platinum-group catalysts in electro-catalytic oxygen reduction, methanol oxidation, and hydrogen evolution (or as a co-catalyst to enhance the electro-catalytic activity of noble metals via synergistic effects). Tungsten carbides can also be used as a non-noble metal co-catalyst for photocatalytic water oxidation and organic pollutant degradation. In this chapter, the electronic structural features (electron donor effect and electron metal support interaction), preparation methods, energy and environmental applications, and typical case analysis of nano tungsten carbides are briefly analyzed and summarized.
Over the past 30 years, there have been significant commercial and academic advances in lithium-ion battery (LIB) technology. Due to its high energy density and long cycle life, LIBs have been widely used in portable electronic devices (including mobile phones, laptop computers, etc.) and have great application prospects in electric two-wheeled vehicles and electric four-wheeled vehicles. Sodium (Na), potassium (K), and zinc (Zn) ion batteries also show broad research prospects. In this chapter, the basic structure, energy storage principle, and electrode material of LIBs and other metal-ion batteres are briefly reviewed.
Graphitic carbon nitride (g-C3N4) has excellent physicochemical properties, including adjustable band gap, large specific surface area, abundant active sites, and easy surface modification. Nanostructured g-C3N4 shows promising application prospects in environmental photocatalysis degradation and energy conversion, electrochemical energy conversion, and storage, where the current applications include photocatalysis, electrocatalysis, batteries, and supercapacitors. The electronic conductivity of g-C3N4 can be improved by carbon composite design, phosphorus doping, and reduction of nitrogen content, which broadens the way for the application of g-C3N4 in the electrochemical and photo-electrocatalysis fields. In this chapter, the structural features, preparation methods, energy and environmental applications, and typical case analysis of nano-g-C3N4 are briefly analyzed and summarized.
Hollow carbon nanocages are special hollow carbon materials and three-dimensional carbon materials with abundant porous structures and surface defect sites (high surface area), good electrical conductivity, and excellent wettability (specific surface functional groups). In electrochemical energy applications, the synergistic effect of these characteristics of hollow carbon nanocages ensures sufficient space for charge storage and fast transport of ions and electrons, resulting in high electrochemical kinetic characteristics and excellent rate performances. In environmental adsorption and photocatalytic applications, the hollow carbon nanocages also have significant advantages such as high adsorption capacity and good light scattering and absorption capacity. In this chapter, the structural features, preparation methods, energy and environmental applications, and typical case analysis of hollow carbon nanocages are briefly analyzed and summarized.
Sulfur nickel compound is a very complex system, and there are many different phases (such as Ni3S2, NiS2, NiS). Among them, Ni3S2 can provide rapid electron transfer due to its room temperature conductivity of about 1.2 × 104 Ω cm, which has higher electrochemical performance and other properties than other nickel sulfides. The Ni3S2 is widely used as material for supercapacitor electrode, lithium-ion battery electrode, water electrolysis catalyst, and so on. The Ni3S2 also be used as environmental catalytic materials in the fields of photocatalysis, electrocatalysis, and thermal catalysis. In this chapter, the structural features, preparation methods, energy and environmental applications, and typical case analysis of nanonickel sulfides (such as Ni3S2) are briefly analyzed and summarized.
Manganese dioxide (MnO2) is an important inorganic functional material with outstanding physical and chemical properties. Meanwhile, MnO2 has abundant resources, low price, and environmental friendliness. The MnO2 nanostructures show satisfactory performance and application prospects in the applications of electrochemical energy storage (supercapacitor and battery) or conversion (electrocatalysis) and environmental remediation or protection (such as adsorption, photocatalysis, advanced oxidation, etc.). The six crystalline types MnO2 (α, β, γ, δ, ε, and λ-MnO2) show the obvious relationship between crystalline phase and catalytic activity. In this chapter, the structural features, preparation methods, energy and environmental applications, and typical case analysis of nano-MnO2 are briefly analyzed and summarized.
The use of energy gas carriers with higher calorific values such as methane (CH4) and hydrogen (H2) for pure chemical or electrochemical forms of energy utilization is the most attractive alternative to limited combustion, carbon-rich and environmentally harmful fossil fuels (such as diesel and gasoline). The selective separation and efficient storage of these energy gases, while reducing the carbon footprint, is recognized as one of the major tasks in the transition to a progressive, sustainable and environmentally friendly society on a global scale. The development of functional microporous materials (including polymers, carbon materials or organic metal materials) is the basis for gas separation and storage. In this chapter, the basic principle, separation and storage mechanism, adsorbing materials and application prospects for the selective separation and storage of various energy gases are briefly reviewed.
Noble metal nanometer materials, including gold (Au), silver (Ag), platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmium (Os), and iridium (Ir), have outstanding electrical properties (such as d electron orbital is vacant and easy adsorption of reactants), catalytic properties (including electrocatalysis, photocatalysis, and thermocatalysis), and other physicochemical properties. The applications of nano-noble metal catalysts have been spread throughout a number of industries such as the electronics, chemical industry, energy, metallurgy, and environment. Synthesis and application of nano-noble metal catalysts is one of the most dynamic sub-disciplines in the field of nanotechnology. In this chapter, the structural features, preparation methods, energy and environmental applications, and typical case analysis of nano-noble metal (specially Pt and Pd) catalysts are briefly analyzed and summarized.
Photocatalysis technology-based appropriate photocatalyst can be used for water pollution remediation and green energy conversion. Bismuth (Bi)-based oxometallates, such as BiVO4, Bi2WO6, Bi2MoO6, and Bi2O2CO3 are excellent candidates for visible-light-responsive photocatalysts. The Bi-based oxometallates electrocatalysts also show very high electrocatalytic activity due to their unique physical and chemical properties and electronic structures. The in-depth studies of various nanostructured Bi-based oxometallates have shown their prominent usefulness and attractive prospect in solving the increasingly serious energy and environmental problems. In this chapter, the structural features, preparation methods, energy and environmental applications, and typical case analysis of nano Bi-based oxometallates are briefly analyzed and summarized.
The adsorption process is the process in which pollutant molecules or ions are adsorbed to the solid surface (the inner surface of porous materials). Usually, the free energy of molecules or ions will be reduced. Therefore, the adsorption process is an exothermic process, and the heat released is called the adsorption heat of the pollutant on the surface of porous materials. The porous adsorption materials (activated carbon and molecular sieve) have strong adsorption capacity for waste gas (volatile organic compounds), waste water (organic molecules and heavy metal ions), and waste residue (water-soluble leaching solution from residue). In this chapter, the basic principle, adsorption mechanism, adsorption functional materials, and application prospects for the adsorption treatment and recycling of "three wastes" (waste gas, waste water and waste residue) are briefly reviewed.
Nanomaterials refer to the three-dimensional spatial scale of at least one dimension in the nanometer scale (1–100 nm), and it is a new generation of materials composed of nano units between the size of atoms (molecules) and macroscopic system. The preparation strategies of nanomaterials include two general directions: bottom-up (from small atom to nanoscale) and top-down (from large block to nanoscale) strategies. Typical preparation methods of nanomaterials include as follows: hydrothermal/solvothermal method, chemical coprecipitation method, sol-gel synthesis method, electrodeposition method, chemical vapor deposition method, high-temperature solid phase method, mechanochemistry method, and other high energy physics methods. In this chapter, we will pay special attention to the description of the definitions/history, physicochemical principles of different synthesis methods, and their paradigm summary of our or other group's work in recent years.
With the depletion of fossil energy and the increase in environmental pollution, the development of new energy materials with porous structures and environmental purification treatment has attracted extensive attention. Among them, porous carbon-based materials with abundant raw materials and low prices have been widely used in clean energy storage and environmental remediation. Porous activated carbon has been widely used because of its high surface area, adjustable pore size, well-developed pore structure, and chemical stability. In this chapter, the structural features, preparation methods, energy and environmental applications, and typical case analysis of porous activated carbon are briefly analyzed and summarized.
