Search

With the increasing severity of the water crisis, electrochemical capacitive deionization has emerged as a promising technology for water purification. Graphene is a powerful candidate among carbon materials for the electrochemical electrode, and monolithic graphene is a high-end material for capacitive deionization considering its potentially large surface area and fast adsorption kinetics. However, monolithic graphene electrode materials still suffer from either weak deionization performances or high manufacturing costs. Herein, a novel electrode material, a porous monolith composed of nitrogen-doped graphene building-blocks, has been developed via low-cost zinc-assisted pyrolysis. The monolith is hydrophilic, possesses a high specific surface area, and has abundant hierarchical mesopores. Remarkable electrochemical capacitive deionization performances are provided by such a graphene monolith, with a salt adsorption capacity of 39.6 mg g−1 and a salt adsorption rate near 3.5 mg g−1 min−1. This development thus underlines the promise of novel monolithic electrode materials for high-efficiency desalination of seawater into freshwater. [ABSTRACT FROM AUTHOR]

We developed an efficient MoS2 nanosheet electrode coupled with CeO2via a hydrothermal process to facilitate water adsorption and dissociation, which displayed good HER activity and stability at a large current density of 500 mA cm−2. In situ Raman spectroscopy confirmed the formation of hydroxide ions based on the strengthening of the Ce–O bond during the HER. [ABSTRACT FROM AUTHOR]

Advanced sorbents for water purification need to be developed for environmental protection. Porous boron nitride (BN) is a high-end material for the removal of pollutants for its remarkable sorption characteristics and chemical inertia. However, it still suffers from thick pore walls, low yield and powdery state, limiting the performance. Herein, a borax-based template-free pyrolysis route is developed to massively produce the cellular monolith of a few-atomic-layered boron nitride. It possesses ultra-thin pore walls and uniform mesopores, resulting from the phase-separation-dominated pore-forming mechanism. Such a porous monolith is applied for water purification, showing high adsorption capacity on Congo red (1096 mg g−1), which is attributed to mesopores and surface polarity. It further exhibits unprecedented recyclability, relying on its anti-oxidation stability. A prototype of the water filter pitcher using this BN is finally demonstrated with commendable performances. The aerogel-like BN bulk material enables a high-capacity recyclable sorbent, representing a leap forward toward practical water purification. [ABSTRACT FROM AUTHOR]

Hollow metal oxides and carbon hybrids with hierarchical and robust nanoarchitecture hold great potential as high-performance electrode materials. Herein, a relatively unexplored hollow and hierarchical metal–organic framework (MOF) assembled by parallel stacked triangular sub-MOFs were successfully synthesized via a facile co-precipitation method. The hollow MOFs were then converted to binary metal oxides@carbon composites, exemplified herein as Zn–Mn mixed oxides@carbon (ZnxMnO@C) hybrids. The obtained ZnxMnO@C inherits the unique hollow hexagonal nanodisks (HHNDs) structure of the MOF precursor, and each triangular plate-like subunit consists of a continuous carbon matrix embedded uniformly within the ultrafine ZnxMnO nanoparticles. When evaluated as an anode material for lithium ion batteries, the ZnxMnO@C HHNDs exhibited high specific capacity (1050 mA h g−1 at 0.1 A g−1 after 200 cycles) and remarkable cycling performance up to 1000 cycles. It is believed that besides the protection of the carbon matrix, the unique hierarchically hollow structure with parallel stacked subunits endows the ZnxMnO@C hybrid with additional capability to withstand lithiation/delithiation strain. Moreover, kinetics-analysis based on cyclic voltammograms (CVs) reveals that the high lithium storage capacity is primarily attributed to fast kinetics originating from pseudocapacitive contribution. This also accounts for the good rate capabilities of ZnxMnO@C HHNDs (713 and 330 mA h g−1 at 1 and 10 A g−1, respectively). Furthermore, full cells with Zn0.5MnO@C anodes and LiMn2O4 cathodes are assembled and show good cycling stability over 120 cycles. This study demonstrates a new hollow structure of MOFs and its usefulness in developing robust and hierarchical metal oxide/carbon composites for electrochemical storage applications. [ABSTRACT FROM AUTHOR]

We developed an efficient MoS 2 nanosheet electrode coupled with CeO 2 via a hydrothermal process to facilitate water adsorption and dissociation, which displayed good HER activity and stability at a large current density of 500 mA cm -2 . In situ Raman spectroscopy confirmed the formation of hydroxide ions based on the strengthening of the Ce-O bond during the HER.