Carbon Materials for Solar Water Evaporation and Desalination

Abstract

generation efficiency by reducing heat loss to the bulk water as well as the environment. [22][23][24] As such, efforts have been made in finding the optimal materials with excellent photothermal conversion and heat localization functions, such as plasmonic metals and semiconductors. [25][26][27][28][29][30][31] Among all the possible candidates, carbon materials demonstrate competitive merits due to their intrinsic high solar absorption, excellent structural tunability, and great processability to fulfill the demanding requirements in interfacial SVG. Carbon materials, especially graphene family, carbon nanotubes, and amorphous carbon composed of graphite carbon, can intrinsically convert solar flux into thermal energy by the excitation-relaxation process, conjugating electrons in unsaturated bonds, which lays the foundation for functioning as solar absorbers. [32] Furthermore, the tunable structures of carbon materials confer various functional properties to the system. The solar absorption ability can be enhanced by tailoring carbon nanotubes into vertically aligned arrays, enabling broad-spectrum absorption by multiply reflections in elongated light paths. [33] The 3D carbon monoliths, such as carbon foam and aerogel, can achieve capillary water uptake and thermal insulation, wherein the interconnected pore structure plays a dominating role in these processes. [34][35][36] More importantly, carbon materials, with great processability in different treatment approaches, can serve as ingredients coupling with other materials to form structured composites, achieving cooperative functionalities beyond individuals. For instance, graphene can be grown on the metal skeleton by chemical vapor deposition (CVD) method, endowing the system with more developed pore structures; 3D printing can fabricate patterned architecture on the chosen matrix, propitious to the interfacial water/thermal behavior regulation. [36,37] Meanwhile, the high natural abundance of carbon materials leads to its easy accessibility, which outperforms other materials. With those attractive advantages, carbon materials are capable of advancing interfacial SVG. [38] In this Review, we systematically summarize the design principles and recent progress of carbon materials in interfacial SVG technology (Figure 1). The parallelism between carbon materials structures and required functions for interfacial SVG is discussed. We then examine the recent progress on different interfacial SVG systems composed of artificial carbon materials (pristine carbon system and carbon-containing composite) and biochar, with the focus on the structure-property relationship. Several strategies for antisalt-fouling in the SVG desalination systems are elaborated. Finally, we underline the remaining challenges and provide perspective directions for future investigations.Seawater desalination is viewed as a promising solution to world freshwater scarcity. Solar assisted desalination is proposed to overcome the high energy consumption in current desalination technologies, as it ...

Carbon Dots: An Excellent Fluorescent Probe for Contaminant Sensing and Remediation

“…Carbon-based nanomaterials have grown in popularity because of their superior optical, mechanical, and electrical properties. [8][9][10] Carbon dots (CDs) are the most popular because of their biocompatibility, abundance of raw materials in nature, low toxicity, and cost-effectiveness. [11,12] CDs were discovered in 2004 during the preparatory treatment of electrophoresis for single-walled carbon nanotubes, [13] and again in 2006 during the laser ablation of cement and graphite powder.…”

Solar Water Evaporation Toward Water Purification and Beyond

“…Over the past decade, materials innovation has played an important role in optimizing heat transfer during water evaporation and tuning the phase change behavior of water toward functional systems (Figure ). The spectrum of materials evolution spans from the molecular level to macroscale, enabling functionalities that cover all aspects relevant to energy and water management, including photothermal conversion, , heat localization, , energy harvesting, , as well as water confinement and activation. , Photothermal materials, such as plasmonic nanoparticles, , semiconductors, , carbon-based materials, , and conjugated polymers, , have been developed for high solar-to-heat conversion efficiency based on constructive concepts, including plasmon resonance, band gap engineering, and optical path prolonging. However, their practical performance is largely restrained by heat losses, which may lead to low solar-to-vapor efficiency .…”

A 3D Opened Hollow Photothermal Evaporator for Highly Efficient Solar Steam Generation

“…To date, various photothermal materials have been synthesized and successfully applied in solar steam generation, such as plasmonic metals, [24][25][26][27] semiconductors, [19,28,29] polymers, [30][31][32] and carbon-based materials. [33][34][35][36] Many of them have exhibited excellent light absorption ability (>95%) across the solar spectrum. Therefore, developing photothermal materials itself has reached a bottleneck for further improving the performance of solar evaporator because it has a little room to further enhance light absorption.…”