The atmospheric CO2 concentration continues a rapid increase to its current record high value of 416 ppm for the time being. It calls for advanced CO2 capture technologies. One of the attractive ...technologies is physical adsorption‐based separation, which shows easy regeneration and high cycle stability, and thus reduced energy penalties and cost. The extensive research on this topic is evidenced by the growing body of scientific and technical literature. The progress spans from the innovation of novel porous adsorbents to practical separation practices. Major CO2 capture materials include the most widely used industrially relevant porous carbons, zeolites, activated alumina, mesoporous silica, and the newly emerging metal‐organic frameworks (MOFs) and covalent‐organic framework (COFs). The key intrinsic properties such as pore structure, surface chemistry, preferable adsorption sites, and other structural features that would affect CO2 capture capacity, selectivity, and recyclability are first discussed. The industrial relevant variables such as particle size of adsorbents, the mechanical strength, adsorption heat management, and other technological advances are equally important, even more crucial when scaling up from bench and pilot‐scale to demonstration and commercial scale. Therefore, we aim to bring a full picture of the adsorption‐based CO2 separation technologies, from adsorbent design, intrinsic property evaluation to performance assessment not only under ideal equilibrium conditions but also in realistic pressure swing adsorption processes.
Divide and conquer: This Review discusses the recent advances in adsorption‐based CO2 separation technology, from porous materials synthesis, adsorbents’ intrinsic property evaluation to performance assessments not only in view of the ideal equilibrium conditions but also in critically practical perspective.
Direct pyrolysis of polymer nanospheres usually leads to severe particle aggregation, uncontrolled surface morphology, and poor solvent dispersibility of the carbonaceous analogues. The successful ...manipulation of surface roughness, surficial mesopores, and water dispersibility of carbon nanospheres (CNSs) is essential to meet their structural varieties and practical applications. In this study, a facile, surface charge‐driven, interfacial assembly method is reported for the synthesis of CNSs with the abovementioned properties, which involve the interfacial assembly between hetero‐charged silica nanoparticles and polymer nanospheres process. Noticeably, the surface area and pore volume of the resultant rough‐surface CNSs can be augmented remarkably compared to those of direct‐pyrolyzed CNSs. Moreover, the cooperation of uniformity and rough‐surface morphology imparts CNSs with good dispersion stability and more adsorption sites for efficiently removing and recovering water pollutants, e.g., fluorescent derivative fluorescein 5(6)‐isothiocyanate; thus, CNSs contribute greatly to environment protection and resource cyclic utilization. These findings may set the foundations for designing and constructing multifarious morphological carbon nanomaterials, with great monodispersity, surficial mesopores and rough surface, for various applications.
A facile, surface charge‐driven, interfacial assembly method for the synthesis of rough‐surface carbon nanospheres (CNSs) by a well‐controlled electrostatic interaction is demonstrated. The surface roughness can be controlled by varying pyrolysis temperature and coverage degree. The cooperation of uniformity and rough‐surface morphology of the CNSs ensures more dispersion stability and more adsorption sites for efficiently removing and recovering water pollutants.
The development of photocatalysts based on covalent organic frameworks (COFs) is intriguing research due to their structural flexibility and tremendous catalytic sites. Herein we demonstrate a facile ...strategy to prepare composite materials of combined COFs and inorganic semiconductors with enhanced photocatalytic performances. A new composite photocatalyst (BiOBr/CTF-3D) integrated three-dimensional (3D) covalent triazine framework (CTF-3D) with two-dimensional BiOBr nanoflake was prepared via a simple coprecipitation method. The structural characterizations demonstrated that the amorphous CTF-3D was well modified on the surfaces of BiOBr. The photocatalytic activity of the BiOBr/CTF-3D composite was evaluated by the degradation of colorless antibiotic agents, tetracycline hydrochloride (TC) and ciprofloxacin (CIP), under visible light irradiation. When the mass percent of CTF-3D was 2%, the BiOBr/CTF-3D composite displayed the highest photocatalytic activity. The enhancement of photocatalytic performance was mainly derived from the enlarged optical adsorption range, the efficiently separated photogenerated electron–hole pairs, and the accelerated adsorption and transfer of antibiotic molecules, in the synergistically facilitating photocatalytic process. In addition, a possible photocatalytic mechanism for degrading TC by BiOBr/CTF-3D-2% was tentatively proposed. This work opens up a new strategy to improve the photocatalytic activity of traditional inorganic photocatalysts by modification with COFs materials for solving the pollution of living ecosystems.
The pyrolysis of metal-organic frameworks has emerged as a promising route to synthesize metal oxides with diverse phase compositions, morphologies, sizes and surface areas. The ...BiOBr/Bi24O31Br10/TiO2 (BBT) heterostructures have been achieved for the first time by calcining BiOBr/MIL-125(Ti) composite at 500°C in air. The BBT-2 composite exhibited the highest photocatalytic performance for degradation of RhB under visible light irradiation. The enhanced photocatalytic activity is attributed to narrower band-gaps and synergistic effect originating from the well-aligned straddling band-structures between BiOBr, Bi24O31Br10 and TiO2, also result in an faster interfacial charge transfer during the photocatalytic reaction. This work could be conductive to the design of heterostructured photocatalysts contained metal oxide by pyrolytic conversion of metal-organic frameworks for significantly improved photocatalytic performance.
A novel BiOBr/Bi24O31Br10/TiO2 heterostructure was achieved by calcining BiOBr/MIL-125(Ti) composite and exhibited the photocatalytic performance for degradation of RhB. Display omitted
•A novel BiOBr/Bi24O31Br10/TiO2 heterostructure was achieved by calcining BiOBr/MIL-125(Ti) composite.•The heterostructure exhibited the photocatalytic performance for degradation of RhB.•The enhanced photocatalytic activity is attributed to synergistic effect between BiOBr, Bi24O31Br10 and TiO2.•This work could be conductive to the design of heterostructured photocatalysts by pyrolytic conversion of MOF.
The in situ growth of Bi-based metal–organic framework (MOF) (CAU-17) on BiOBr 2D material was prepared for the first time by using a facile solvothermal transformation approach. The BiOBr was ...applied both as template to support the growth of MOF and as Bi3+ source of MOF. The BiOBr/CAU-17-2h composite exhibited enhanced photocatalytic activity for degradation of Rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) under visible light irradiation, suggesting a good synergy between BiOBr and CAU-17 MOF.
To improve photocatalytic activity of 2D BiOBr nanosheets, Bi2S3 nanoparticles were introduced to fabricate the hybrid composite using co-precipitation method. The Bi2S3 loading 15 wt% amount of ...as-prepared composite shows the optimal visible light-driven photocatalytic activity for the degradation of Rhodamine B (RhB), tetracycline hydrochloride (TC) and ciprofloxacin (CIP). Radicals trapping experiments are further conducted to detect the reactive active species generated during the irradiation of BiOBr/Bi2S3-15 photocatalyst. It demonstrated that h+ and ∙O2− play the key role in photocatalytic degradation of pollutants. Photocurrent response, EIS and PL spectra reveal that the enhanced photocatalytic performance of BiOBr/Bi2S3 hybrid material shows higher separation efficiency of the photo-generated electron–holes pairs.
The hybrid material combined Bi2S3 nanoparticles with BiOBr nanosheets shows the enhanced visible light-driven photocatalytic activity for the degradation of RhB, TC and CIP. Display omitted
•The Bi2S3 nanoparticles and BiOBr nanosheets were successfully fabricated together.•The hybrid material shows the enhanced visible light-driven photocatalytic activity.•The hybrid material shows higher separation efficiency of photo-generated electron–holes pairs.•The h+ and ∙O2− play the key role in photocatalytic degradation of pollutants.
ZnCo2O4 has become one of the most widely used anode materials due to its good specific capacity, cost-efficiency, high thermal stability and environmental benignity. However, its poor conductivity ...and cycle stability have limited its practical application in lithium-ion batteries. To overcome these issues, we constructed a 3D nanoflower composite material (ZnCo2O4@C3N4-B) by combining ZnCo2O4 as a framework and B-doped g-C3N4 (g-C3N4-B) as a new carbon source material via a simple hydrothermal method. ZnCo2O4@C3N4-B exhibited exceptional specific capacitance of 919.76 mA h g−1 after 500 cycles at 0.2 A g−1 and a long-term capacity retention of 97.8% after 1000 cycles at 2 A g−1. The high reversible capacity, long cycling life and good rate performance could be attributed to the 3D interconnected architecture and doping of g-C3N4-B. This work provides a simple and general strategy to design high-performance anode materials for lithium-ion batteries to meet the needs of practical applications.
The idea of sulfidation of metal-organic frameworks (MOFs) has provided a prospective routing to synthesize metal sulfides, which has all kinds of shapes here. Herein, the invaginated hexagonal In2S3 ...nanorods with hollow structure were successfully fabricated by sulfidation of In-MOF (MIL-68-In) precursor. The obtained In2S3–8h exhibits high catalytic performance for the photodegradation of tetracycline hydrochloride (TC) and methyl orange (MO). The advantageous crystallinity and optical property have effectively promoted more an efficient separation of photo-induced electron–hole pairs, resulting in the enhanced photocatalytic activity. In this work, we put forward a new strategy, which aims to synthesize the traditional semiconductor photocatalysts by sulfidation of MOFs for eliminating environmental pollutions.
The In2S3 nanorods were fabricated by sulfidation of In-MOF precursor, which exhibits high photocatalytic activity for the removal of methyl orange (MO) dye and tetracycline hydrochloride (TC) antibiotics. Display omitted
•The In2S3 nanorods were fabricated by sulfidation of In-MOF precursor.•The In2S3–8h exhibits high photocatalytic activity for the removal of methyl orange (MO).•The In2S3–8h can photodegrade tetracycline hydrochloride (TC) antibiotics.
T
he urgency of dealing with global climate change caused by greenhouse gas(GHG) emissions is increasing as the carbon dioxide(CO
2
) concentration in the atmosphere has reached a record high value ...of 416 ppm(parts per million). Technologies that remove CO
2
from the surrounding air(direct air capture, DAC) could result in negative carbon emissions, and thus attracts increasing attention. The steady technical progress in adsorption-based CO
2
separation greatly advanced the DAC, which largely relies on advanced sorbent materials. This review focuses on the latest development of porous solids for air capture; first discussed the main types of sorbents for air capture, which include porous carbons, zeolites, silica materials, and metal-organic frameworks(MOFs), particularly their modified counterparts. Then, we evaluated their performances, including uptake and selectivity under dry and humid CO
2
streams for practical DAC application. Finally, a brief outlook on remaining challenges and potential directions for future DAC development is given.
Selective separation of ethylene and ethane (C
H
/C
H
) is a formidable challenge due to their close molecular size and boiling point. Compared to industry-used cryogenic distillation, adsorption ...separation would offer a more energy-efficient solution when an efficient adsorbent is available. Herein, a class of C
H
/C
H
separation adsorbents, doped carbon molecular sieves (d-CMSs) is reported which are prepared from the polymerization and subsequent carbonization of resorcinol, m-phenylenediamine, and formaldehyde in ethanol solution. The study demonstrated that the polymer precursor themselves can be a versatile platform for modifying the pore structure and surface functional groups of their derived d-CMSs. The high proportion of pores centered at 3.5 Å in d-CMSs contributes significantly to achieving a superior kinetic selectivity of 205 for C
H
/C
H
separation. The generated pyrrolic-N and pyridinic-N functional sites in d-CMSs contribute to a remarkable elevation of Henry selectivity to 135 due to the enhancement of the surface polarity in d-CMSs. By balancing the synergistic effects of kinetics and thermodynamics, d-CMSs achieve efficient separation of C
H
/C
H
. Polymer-grade C
H
of 99.71% purity can be achieved with 75% recovery using the devised d-CMSs as reflected in a two-bed vacuum swing adsorption simulation.
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