Nanjing Tech University

About: Nanjing Tech University is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Catalysis & Membrane. The organization has 21827 authors who have published 21794 publications receiving 364050 citations. The organization is also known as: Nangongda & Nánjīng Gōngyè Dàxúe.

The peculiar effect of water on ionic liquids and deep eutectic solvents

Abstract: Ionic liquids (ILs) and deep eutectic solvents (DESs) have been suggested as eco-friendly alternatives to organic solvents. A trace amount of water is often unavoidable as impurity, and water is also added on purpose to reduce their problematically high viscosity and lower their high price. Understanding the distinct effects of water on the properties of ILs/DESs is highly important. In this review, we collect published experimental and theoretical results for IL/DES–H2O systems at varied water concentrations and analyze them. Results from mechanistic studies, thermodynamic modelling and advanced experiments are collected and critically discussed. Six commonly studied IL/DES–H2O systems were selected to map experimental observations onto microscopic results obtained in mechanistic studies. A great variety of distinct contours of the excess properties can be observed over the entire compositional range, indicating that the properties of IL/DES–H2O systems are highly unpredictable. Mechanistic studies clearly demonstrate that the added H2O rapidly changes the heterogeneous 3D structures of pure ILs/DESs, leading to very different properties and behaviour. There are similarities between aqueous electrolytes and IL/DES solutions but the bulky and asymmetric organic cations in ILs/DESs do not conform to the standard salt dissolution and hydration concepts. Thermodynamic modelling previously assumes ILs/DESs to be either a neutral ion-pair or completely dissociated ions, neglecting specific ion hydration effects. A new conceptual framework is suggested for thermodynamic modelling of IL/DES–H2O binary systems to enable new technologies for their practical applications.

Shape Conformal and Thermal Insulative Organic Solar Absorber Sponge for Photothermal Water Evaporation and Thermoelectric Power Generation

Abstract: DOI: 10.1002/aenm.201900250 can attain the highest achievable conversion efficiency and enable a broad range of applications, including domestic heating, brine desalination, wastewater purification, steam sterilization, and power generation.[1–7] One actualization of solarto-thermal technology, solar-driven water evaporation can directly transfer heat to drive evaporation using sunlight as the only power input.[8–15] Compared with the conventional solar-driven steam generation system which requires high optical devices and large footprints investment, the emerging interfacial photothermal water evaporation based on nanostructured solar receiver materials restrict the solar heat at the water–air interface to suppress the heat losses and enhance the conversion efficiency. To date, significant progress in preparation of solar absorber materials, including semiconductors,[16–18] metallic,[19–21] and carbonaceous nanomaterials,[22–25] alongside with prudent system designs, e.g., environmental enhancement,[26–28] optical,[28–30] and thermal management[31–33] have been made to improve solar energy conversion efficiency. However, extended and collaborative utilization of nonconcentrated solar energy conversion for practical applications is making a little headway due to inconsequential/conflicting outcomes. On one hand, the heat losses from the solar absorber to bulk water and surrounding air for water vaporization are inevitable. On the other hand, constructive low-grade solar heat harvesting during evaporation are rarely reported. Therefore, effective thermal management and synergic utilization of the solar steam generation are essential. Another major roadblock toward photothermal technological advancement is the accessibility to a robust and practical material structure for practical deployment. As such, lightweight, load bearing, weather resistant, and uncommonly shape adaptive solar absorber materials are long sought after for durable outdoor application. Herein, we report a 3D organic bucky sponge that is collectively elastic, broadband light absorbing, and heat insulative that enables desired combination of efficient solar thermal conversion and mechanical stability. The 3D cellular truss is highly compressible and elastic which assumes excellent shape conformity and recovery, particularly beneficial to maximize space usage as well as for flexible, resilient outdoor purposes. Importantly, a rational integration of efficient solar water Solar-driven interfacial vaporization by localizing solar-thermal energy conversion to the air–water interface has attracted tremendous attention due to its high conversion efficiency for water purification, desalination, energy generation, etc. However, ineffective integration of hybrid solar thermal devices and poor material compliance undermine extensive solar energy exploitation and practical outdoor use. Herein, a 3D organic bucky sponge that has a combination of desired chemical and physical properties, i.e., broadband light absorbing, heat insulative, and shape-conforming abilities that render efficient photothermic vaporization and energy generation with improved operational durability is reported. The highly compressible and readily reconfigurable solar absorber sponge not only places less constraints on footprint and shape defined fabrication process but more importantly remarkably improves the solar-to-vapor conversion efficiency. Notably, synergetic coupling of solar-steam and solar-electricity technologies is realized without trade-offs, highlighting the practical consideration toward more impactful solar heat exploitation. Such solar distillation and low-grade heat-to-electricity generation functions can provide potential opportunities for fresh water and electricity supply in off-grid or remote areas.