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The transmittance spectra of (a) Cs x WO 3 nanorods synthesized by WCRSP process; (b) commercial ITO glass (5 ³/□); (c) commercial ITO glass (10 ³/□). The dash lines show corresponding reflectance spectra. (R-a, R-b, R-c). The background shows the relative energy wavelength distribution of solar spectrum on the sea level. Inset presents the enlarge area of UV light region and the thermographic images of after IR light irradiation. Reproduced from Ref. 71 with permission from The Royal Society of Chemistry.
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Various kinds of optical responsive ceramic nanomaterials and films were successfully synthesized by environmental friendly green processes, such as hydrothermal/solvothermal process, mechanochemical doping process, oxygen plasma treatment process and a water molecular controlled-release solvothermal process (WCRSP). The composites combined the hig...
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In this work, the carbon quantum dot (CQD)-decorated BiFeO3 nanoparticle photocatalysts were prepared by a hydrothermal method. The TEM observation and XPS characterization indicate that the CQDs are well anchored on the surface of BiFeO3 nanoparticles. Acid orange 7 (AO7) and hexavalent chromium (Cr(VI)) were chosen as the model pollutants to inve...
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... Morphologically controllable nitrides such as gallium nitrides (GaN) show promise for use in gas-sensing applications [7][8][9]. However, the need for room temperature sensing has become more pressing in light of the need for more environmentally friendly processes [10]. ...
... It is universally acknowledged that the key point of photocatalysis is to develop highly effective and stable photocatalysts. Since the pioneering work of Fujishima and Honda in 1972 [28], a great number of photocatalysts have developed to be used in energy conversion and environmental remediation [1,21,[43][44][45][46][47][48][49][50]. The reported photocatalysts include metal oxides such as Fe 2 O 3 [51,52], WO 3 [53] , TiO 2 [54] and ZnO [55]; metal sulfides such as ZnS [56], CdS [57] and CuS [58]; bismuth-based photocatalysts such as BiOX (X = I, Br, Cl) [59] and Bi 2 MO 6 (M = Mo, W) [60]; metal-organic frameworks (MOFs) [61]; covalent organic frameworks (COFs) [62] and many more. ...
Nitrogen oxides (NOx) pollutants can cause a series of environmental issues, such as acid rain, ground-level ozone pollution, photochemical smog and global warming. Photocatalysis is supposed to be a promising technology to solve NOx pollution. Graphitic carbon nitride (g-C3N4) as a metal-free photocatalyst has attracted much attention since 2009. However, the pristine g-C3N4 suffers from poor response to visible light, rapid charge carrier recombination, small specific surface areas and few active sites, which results in deficient solar light efficiency and unsatisfactory photocatalytic performance. In this review, we summarize and highlight the recent advances in g-C3N4-based photocatalysts for photocatalytic NOx removal. Firstly, we attempt to elucidate the mechanism of the photocatalytic NOx removal process and introduce the metal-free g-C3N4 photocatalyst. Then, different kinds of modification strategies to enhance the photocatalytic NOx removal performance of g-C3N4-based photocatalysts are summarized and discussed in detail. Finally, we propose the significant challenges and future research topics on g-C3N4-based photocatalysts for photocatalytic NOx removal, which should be further investigated and resolved in this interesting research field.
... As shown in Fig. 1a, Na x WO 3 (NaWO) nanoparticles are obtained by employing a solvothermal method [44]. First, NaOH (1.80 g) was added to 300 mL of benzyl alcohol solution and stirred for 30 min. ...
Transparent heat-insulation glass (HIG) with a highly selective light-absorbing coating and an energy-storage blanket (ESB) loaded with phase change materials show considerable potential in reducing building energy consumption. However, the energy-saving effect of a single material is usually not ideal, and the instability of HIG and ESB limits their applications. In this work, HIG with enhanced stability and a form-stable ESB was prepared. The temperature difference between various indoor areas and energy consumption were reduced simultaneously because of the temperature regulation function of the HIG and ESB in the light and dark areas. Na x WO 3 @SiO 2-coated HIG showed excellent daylighting and near-infrared-light-shielding ability with visible light transmittance of 71% and near-infrared light transmittance of 16%, respectively. Moreover, polyethylene glycol/halloysite nanotube composite phase change material with a high enthalpy of 71.1 J/g and a suitable phase change temperature of 27.5 • C was prepared for the form-stable ESB. The test room experiment indicated that the combination of the HIG and ESB (HIG-ESB) reduced the indoor temperature difference from 6.8 • C to 0.9 • C and the maximum temperature by 33-40%. The energy consumption simulation revealed that the ESB can save energy in all selected cities, whereas HIG is only applicable to cities in warm regions. HIG-ESB achieved the highest annual energy-saving rate of 43.9% in Hong Kong. The joint application of the HIG and ESB provides a new strategy for developing passive energy-saving buildings.
... Since water photolysis was discovered by Fijishima et al. [1] with TiO2 as a photocatalyst for the production of O2 and H2 from water, many kinds of semiconductors have been fabricated and applied as photocatalysts, especially for the widely studied oxide materials. It is accepted that the properties of materials greatly changed according to their synthesis process, chemical components, morphologies, surface modification, elements doping and the formation of composites etc. [2][3][4][5][6][7]. The simple binary metal oxides or metal-free semiconductors, such as TiO2, ZnO, WO3 and C3N4, etc., have been widely studied as photocatalysts to understand the fundamental principle, the improvement of photocatalytic efficiency and the expansion in other potential applications [8][9][10][11][12][13]. ...
Ternary metal oxides (TMOs) with flexible band structures are of significant potential in the field of photocatalysis. The efficient utilization of renewable and green solar energy is of great importance to developing photocatalysts. To date, a wide range of TMOs systems has been developed as photocatalysts for water and air purification, but their practical applications in visible light-assisted chemical reactions are hindered mainly by its poor visible light absorption capacity. Introduction of N atoms into TMOs can narrow the band-gap energy to a lower value, enhance the absorption of visible light and suppress the recombination rate of photogenerated electrons and holes, thus improving the photocatalytic performance. This review summarizes the recent research on N-modified TMOs, including the influence of N doping amounts, N doping sites, and N-induced phase transformation. The introduced N greatly tuned the optical properties, electronic structure, and photocatalytic activity of the TMOs. The optimal N concentration and the influence of N doping sites are investigated. The substitutional N and interstitial N contributed differently to the band gap and electron transport. The introduced N can tune the vacancies in TMOs due to the charge compensation, which is vital for inducing different activity and selectivity. The topochemical ammonolysis process can convert TMOs to oxynitride with visible light absorption. By altering the band structures, these oxynitride materials showed enhanced photocatalytic activity. This review provides an overview of recent advances in N-doped TMOs and oxynitrides derived from TMOs as photocatalysts for environmental applications, as well as some relevant pointers for future burgeoning research development.
... Not only the temperature but also the pressure control of the reaction system, together with the use of additives, the particle morphology and size of the product, crystal structure, crystal plane, crystallinity, etc. can be efficiently controlled. Therefore, it has been accepted that the hydrothermal or solvothermal processes show great potential for improving the functionality of various materials, and offer many applications such as non-toxic pigments, photocatalysts, ultraviolet rays, and infrared shielding materials etc. (Cao et al., 2022;Guo et al., 2010;Hermawan et al., 2021;Taufik et al., 2020;Xue and Yin, 2022;Yin, 2015;Yin and Asakura, 2019). The liquid phase reactions proceed under mild conditions compared to high-temperature methods such as solid-phase reactions, which are environmentally friendly. ...
It is well known that the functionality of inorganic materials strongly depends on the chemical composition, morphology, particle size, crystal facet, etc., which are strongly influenced by the synthesis process. The precise control of the synthesis process is expected to lead to the discovery of new functionality and improvement of the functionality of materials. For example, in a high-temperature solid-phase reaction, it is difficult to control the morphology of nanocrystals. On the other hand, synthesizing functional materials using solution processes, such as hydrothermal and solvothermal reactions, makes it possible to control the morphology and particle size precisely. Usually, the solution process is strongly related to the dissolution reprecipitation mechanism. Therefore, the material composition can be strictly controlled and is suitable for forming fine particles with high crystallinity. In this review paper, the role of the solvent in the solution process, its effect on particle size and morphology of the transition metal oxide, and the related functional improvement will be focused. Furthermore, the direct formation of functional thin films by the solution process and the morphology control by non-oxide materials by the topotactic reaction will also be introduced.
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... For example, an energy storage blanket (ESB) based on phase change materials (PCMs), which are usually applied to walls, can reduce indoor temperature fluctuations by absorbing and releasing heat during phase change, thereby reducing the use of air conditioning [4]. Heat-insulating glass (HIG) with selective sunlight absorption capacity, which can be used for windows or curtain walls, can reduce the indoor temperature by isolating most of the radiation energy of near-infrared (NIR) light [5,6]. At present, research on energy savings based on glass and walls is mostly carried out separately; thus, only local temperature regulation can be realized, and there is often an obvious temperature difference. ...
... The KWO nanoparticles were prepared by a solvothermal method [6], as shown in Fig. 1b. Specifically, 0.90 g KOH was first added to 150 mL benzyl alcohol solution and stirred for 20 min. ...
The energy shortage crisis is one of the main challenges facing human society. Energy storage blanket (ESB) based on phase change material (PCM) and transparent heat-insulating glass (HIG) based on selective light-absorbing materials show great potential in regulating temperature and reducing building energy consumption. However, the stability of ESB and HIG is insufficient, and there is often a substantial indoor temperature difference when ESB and HIG are applied alone. In this research, stability-enhanced HIG and ESB were prepared. The oxidation and the decline in the heat insulation ability of HIG in air were solved by coating SiO2 film on the surface of KxWO3 nanoparticles. The low thermal conductivity and the deformation during the phase change process of ESB were solved by encapsulating PCM with expanded graphite. The combined use of HIG and ESB (HIG-ESB) reduces the temperature difference in the test room from 5.9 to 0.5 °C and the maximum indoor temperature from 50.5–56.4 °C to 28.5–28.9 °C. The energy-saving rates of ESB, HIG, and HIG-ESB in different climatic regions of China are evaluated by numerical simulation. The results show that ESB can save energy in all regions, while the HIG increases energy consumption in cold areas and can achieve a stronger energy-saving effect than ESB in mild areas such as Hong Kong and Changsha.
... Carbon-doped TiO 2 shows great photocatalytic activity by destructing NO and removal of methyl orange in visible light [26]. Besides nitrogen and carbon-doped titania compounds, there are several compounds such as Nd/C co-doped TiO 2 [27], Fe/N co-doped TiO 2 [28,29]. Along with these, there are also anion doped strontium titania compounds which exhibit excellent photocatalytic activity [30][31][32]. ...
Rapid growing energy demands owing to the reduction of fossil fuels as well as environmental pollution call for renewable, environment-friendly energy sources. Photocatalysis has widely applied for water splitting to generate H2, oxygen evolution, organic synthesis, pollutants degradation, and much more. Today, various multi-anion materials are used, which are synthesized via easy and environment-friendly methods. The multi-anion materials mainly consist of N/C/O, S/O, N/F/O, and N/O, which shows excellent photocatalytic activity. Also, multi-anion contains metal cations and two anionic species. Multi-anion photocatalysts have vast absorption bands and visible-light absorption efficiency. This review discusses the basic information of multi-anion compounds like synthesis, physical and chemical properties. Meanwhile, some research progress of multi anion materials was also given for CO2 reduction, water splitting, and pollutants removal.
... Interestingly, the sensing property of GaN gas has dramatically exceeded its respective oxide (β-Ga 2 O 3 ) performance. Addi-tionally, wide bandgap semiconductors are promising candidates for high-temperature sensor applications due to their resilience to harsh environments (extreme temperatures, acid/basic conditions, high humidity) chemical stability, and mechanical robustness [7][8][9][10][11]. Aluminum nitride (AlN), another group-III nitride with a wide bandgap greater than 6.2 eV, is well known for electronic packaging in high-performance computing due to its high thermally conductive, mechanical, and chemical stability [12]. ...
Hydrogen is a promising renewable energy source for fossil-free transportation and electrical energy generation. However, leaking hydrogen in high-temperature production processes can cause an explosion, which endangers production workers and surrounding areas. To detect leaks early, we used a sensor material based on a wide bandgap aluminum nitride (AlN) that can withstand a high-temperature environment. Three unique AlN morphologies (rod-like, nest-like, and hexagonal plate-like) were synthesized by a direct nitridation method at 1400°C using γ-AlOOH as a precursor. The gas-sensing performance shows that a hexagonal plate-like morphology exhibited p-type sensing behavior and showed good repeatability as well as the highest response (S = 58.7) toward a 750 ppm leak of H2 gas at high temperature (500°C) compared with the rod-like and nest-like morphologies. Furthermore, the hexagonal plate-like morphology showed fast response and recovery times of 40 and 82 s, respectively. The surface facet of the hexagonal morphology of AlN might be energetically favorable for gas adsorption-desorption for enhanced hydrogen detection.
... 7 Many different types of NO x sensor and photocatalyst materials have been extensively studied, especially semiconductor metal oxides (SMOX) owing to their tailorable physical and chemical properties. 3,[8][9][10][11][12][13] Consequently, SMOX exhibit very promising and outstanding performances together with reversibility and long term stability. Nickel oxide (NiO) is a rock-salt-type metal oxide and well-known p-type semiconductor metal oxide with the multifunctionality of environmentally beneficial applications such as photocatalysis and sensing of the hazardous gases. ...
Nitrogen oxides (NOx) are poisonous gas to humans and the environment and needed to monitor at an early stage. On the other hand, facet design on metal oxide semiconductors is an efficient approach to boost their gas sensing and photocatalytic performances due to desirable active sites. However, in a rock-type structure NiO, a highly polar (111) exposed facets in NiO with rock-salt structure cannot be easily exposed due to its thermodynamically unfavorable. Herein, we demonstrate the synthesis of NiO with a dominantly (111) facet from the transformation of NiOHCl with a layered structure. Among other crystal facets, NiO-Octa (111) exhibited the best NOx gas sensing response (16.5 %) to 300 ppb level and deNOx photocatalytic ability over 50% under UV irradiation. The DFT calculation revealed that the abundance of Ni atoms in the clean (111) surface layer allows the favorable adsorption of N adatoms, forming the Ni-N bond. The charge transfer took place from NiO to NO orbital has proven to be a cause of bond weakening and stretching from 1.1692 Å to 1.2231 Å, leading to NOx molecular decomposition, consistent with the experimental results.
... Recently, morphological controllable nitrides such as GaN, etc. were also utilized a gas sensing applications [8,9]. Therefore, room temperature sensing is highly demanded, since the environmental-friendly green chemical process is very important for future applications [10]. ...
Molybdenum sulfide (MoS2) was engineered by intercalation of ethylene glycol to form 2H (semiconductor) and 1T (metallic) phases. MoS2 was successfully synthesized under solvothermal conditions with different solvents. Water, ethylene glycol (EG), and a mixture of water and EG were used as the solvent. The obtained samples were denoted as MoS2 (W), MoS2 (EG), and MoS2 (EG:W), respectively. The use of ethylene glycol as a solvent expands the (0 0 2) lattice spacing which indicated the expansion of interlayer spacing by intercalation of EG through solvothermal reaction. The MoS2 intercalated with EG possessed higher 1T phase compared to MoS2 without any intercalation. The obtained MoS2 was applied for room temperature toluene sensing with different relative humidity (RH, 20, 40, 60, 80%). The increase of relative humidity could continuously increase the base resistance and also the sensing response of MoS2 (W) and MoS2 (EG:W). For MoS2 (EG), 60% relative humidity showed the optimum condition for sensing applications. The all MoS2 (W), MoS2 (EG), and MoS2 (EG:W) had good sensing performance at 60% RH with sensing ability (ΔR/Rair%) in 100 ppm toluene around 12.50, 14.53, 16.29%, respectively. 1T-MoS2 is taking a major contribution on the sensing properties of MoS2.
