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Strategies for regulating the electronic structure of transition-metal-based electrocatalysts through doping, heterostructure, oxygen vacancies, alloy, and strain engineering are investigated.

Thermoelectric (TE) materials could provide an efficient means for recovering waste heat energy if a low cost, scalable, and high figure-of-merit material could be fabricated. Here, we report, for the first time, a wet ball-milling method to achieve high-performance two-dimensional (2D) semi-metallic TiS2 nanoplatelets. TiO2 is milled, annealed, and sintered with sulfur under high pressure. The addition of a small amount of sulfur (S) powder during the annealing period prevents sulfur deficiency in the sintered compact, resulting in the formation of a near-stoichiometric TiS2 composition. The formation of 2D TiS2 nanoplatelets was confirmed by X-ray diffraction, field emission scanning electron microscopy with energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. The TE properties were measured in the temperature range of 25–100 °C. Further, we obtain that the prepared TiS2 has as high figure of merit as 0.35 at 100 °C. Novel wet ball mill processing strategies for the development of high-performance 2D materials such as TiS2 make it possible to incorporate these materials for scaled-up device fabrication.

Through accumulation, mercury contamination in aquatic systems still poses serious health risks despite the strict regulations on drinking water and industrial discharge. One effective strategy against this is adsorptive removal, in which a suitably functionalized porous material is added to water treatment protocols. Thiol (SH) group-grafted structures perform commendably; however, insufficient attention is paid to the cost, scalability, and reusability or how the arrangement of sulfur atoms could affect the Hg

Self-assembly of block copolymers (BCPs) is an alternative patterning technique that promises high resolution and density multiplication with lower costs. The defectivity of the resulting nanopatterns remains too high for many applications in microelectronics and is exacerbated by small variations of processing parameters, such as film thickness, and fluctuations of solvent vapor pressure and temperature, among others. In this work, a solvent vapor annealing (SVA) flow-controlled system is combined with design of experiments (DOE) and machine learning (ML) approaches. The SVA flow-controlled system enables precise optimization of the conditions of self-assembly of the high Flory-Huggins interaction parameter (χ) hexagonal dot-array forming BCP, poly(styrene-b-dimethylsiloxane) (PS-b-PDMS). The defects within the resulting patterns at various length scales are then characterized and quantified. The results show that the defectivity of the resulting nanopatterned surfaces is highly dependent upon very small variations of the initial film thicknesses of the BCP, as well as the degree of swelling under the SVA conditions. These parameters also significantly contribute to the quality of the resulting pattern with respect to grain coarsening, as well as the formation of different macroscale phases (single and double layers and wetting layers). The results of qualitative and quantitative defect analyses are then compiled into a single figure of merit (FOM) and are mapped across the experimental parameter space using ML approaches, which enable the identification of the narrow region of optimum conditions for SVA for a given BCP. The result of these analyses is a faster and less resource intensive route toward the production of low-defectivity BCP dot arrays via rational determination of the ideal combination of processing factors. The DOE and machine learning-enabled approach is generalizable to the scale-up of self-assembly-based nanopatterning for applications in electronic microfabrication.

Non-redox carbon dioxide utilization through cycloaddition of CO2 to epoxides offers great promise but suffers from lack of heterogeneous catalysts that don’t need additives or pressure. Here we report a systematic post-synthetic modification procedure on a highly porous hydrocarbon framework for efficient grafting of quaternary ammonium salts. The active sites were tuned and characterized while maintaining the porous structure. The metal free and cost-effective catalysts showed quantitative selectivity and very high conversion yields in atmospheric pressure catalysis for cyclic carbonate formation from CO2 and epoxides. The reaction proceeded without additives or co-catalysts, and tolerant for a wide substrate scope. We found that the steric hindrance of the alkyl units on ammonium salts affect microporosity, CO2 binding and the kinetics of cycloaddition reactions. The catalysts were also recyclable, an attractive prerequisite for industrial implementation.

Here, we have employed principal component analysis (PCA) and linear discriminant analysis (LDA) to analyze the Mie-calculated UV-Vis spectra of gold nanospheres (GNS). Eigen spectra of PCA perform the Fano-type resonances. PCA vector spectra determine the 3D vector fields which reveal the homoclinic orbit strange attractor. Quantum confinement effects are observed by the 3D representation of LDA. Standing wave patterns resulting from oscillations of ion-acoustic phonon and electron waves are illustrated through the eigen spectra of LDA. Such capabilities of GNPs have brought high attention to the high energy density physics applications. Furthermore, accurate prediction of gold nanoparticle (GNP) sizes using machine learning could provide rapid analysis without the need for expensive analysis. Two hybrid algorithms consist of unsupervised PCA and two different supervised ANN have been used to estimate the diameters of GNPs. PCA-based artificial neural networks(ANN) were found to estimate the diameters with a high accuracy.

Urban mining of precious metals from electronic waste, such as printed circuit boards (PCB), is not yet feasible because of the lengthy isolation process, health risks, and environmental impact. Although porous polymers are particularly effective toward the capture of metal contaminants, those with porphyrin linkers have not yet been considered for precious metal recovery, despite their potential. Here, we report a porous porphyrin polymer that captures precious metals quantitatively from PCB leachate even in the presence of 63 elements from the Periodic Table. The nanoporous polymer is synthesized in two steps from widely available monomers without the need for costly catalysts and can be scaled up without loss of activity. Through a reductive capture mechanism, gold is recovered with 10 times the theoretical limit, reaching a record 1.62 g/g. With 99% uptake taking place in the first 30 min, the metal adsorbed to the porous polymer can be desorbed rapidly and reused for repetitive batches. Density functional theory (DFT) calculations indicate that energetically favorable multinuclear-Au binding enhances adsorption as clusters, leading to rapid capture, while Pt capture remains predominantly at single porphyrin sites.

Precious-metal recovery from industrial wastewater has received considerable attention because of rapidly increasing amounts of electronic waste. Existing technologies have yet to be widely applied...

A hypercrosslinked ultramicroporous and ordered organic polymer network was synthesized from a planar trimer indole building block called triazatruxene (TAT) through anhydrous FeCl3 catalyzed Fried...

Gold electroless plating for surface finishing of electronic circuits, named electroless nickel immersion gold (ENIG), is widely practiced in the electronics packaging industry. Noncyanide substitu...

Overcoming surface defects Dry reforming of methane with carbon dioxide creates a mixture of hydrogen and carbon monoxide—synthesis gas—which can be converted into liquid fuels. However, heterogeneous catalysts for this reaction are prone to deactivation through unwanted carbon deposition (coking) and loss of surface area of adsorbed metal nanoparticles through agglomeration (sintering). Y. Song et al. used highly crystalline fumed magnesium oxide to support molybdenumdoped nickel nanoparticle catalysts (see the Perspective by Chen and Xu). On heating, the nanoparticles migrated on the oxide surface to step edges to form larger, highly stable nanoparticles. This process also passivated sites for coking on the oxide to produce a catalyst with high activity and longevity at 800°C. Science , this issue p. 777 ; see also p. 737

Interface engineering is a powerful strategy for modulating electronic structure and enhancing intrinsic activity of electrocatalysts for water splitting. Here, we grew two-dimensional (2D) cobalt iron hydroxide (CoFe-OH) nanosheets on nickel foam substrates and deposited FeOOH nanoparticles in a rapid and scalable wet chemical approach. The CoFe-OH@FeOOH nanocomposite features plenty of abundant active sites and high surface area, allowing fast kinetics in an electrochemical water splitting. The new electrode reveals a low overpotential value of 200 mV at 50 mA cm−2 for oxygen evolution reaction (OER). When used as both anode and cathode for overall water splitting, CoFe-OH@FeOOH boosted a low cell voltage of 1.56 V to deliver 10 mA cm−2 current density. The synergistic activity is presumed to be from the seamless interface of CoFe-OH and FeOOH, improving conductivity and mass transfer. We envision that this simple approach offers a new direction for designing efficient electrodes for energy conversion and storage.

Scalability, cost, and feasibility of porous structures in gas capture are prerequisites for emerging materials to be promising in the industry. Herein, a simpler variant of Friedel−Crafts’ synthesis of highly porous covalent organic polymers (COPs) based on an unprecedented solvent‐mediated crosslinking is presented. Alkyl chlorides behave as both solvents and linkers in the presence of AlCl3. Studies on three classes of 18 different monomers using dichloromethane, chloroform, and 1,2‐dichloroethane lead to producing 29 new COPs (124−152). Polymers are characterized by Fourier‐transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, elemental composition analysis, scanning electron microscope (SEM), thermogravimetric analysis (TGA), and porosity analyzer. The synthesized COPs exhibit structures from nonporous to highly porous morphologies with Brunauer–Emmett–Teller (BET) surface areas as high as 1685 m2 g−1. These COPs show high gas uptake toward CO2 (up to 4.71 mmol g−1 at 273 K, 1.1 bar), CH4 (up to 1.31 mmol g−1 at 273 K, 1.1 bar), and H2 (up to 2.02 wt% at 77 K, 1.1 bar). The findings point to significant potential in producing sustainable porous materials through simple and scalable methodology developed here.

Formic acid is a compelling chemical storage platform for hydrogen gas, but the lack of an efficient dehydrogenation catalyst is preventing its commercial use. In this issue of Matter, Wang et al. report a fine-tuned zirconium metal-organic framework with palladium nanoparticles that effectively dehydrogenates formic acid without degradation.

Funding Information: C.T.Y. acknowledges funds provided by the King Abdullah University of Science and Technology (KAUST). E.S.C. acknowledges the support by the International Energy Joint R&D Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No. 20188520000570) and also by National R&D Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT (2021R1A2C2010017). Publisher Copyright: © 2021 Wiley-VCH GmbH Ordered mesoporous carbon materials offer robust network of organized pores for energy storage and catalysis applications, but suffer from time-consuming and intricate preparations hindering their widespread use. Here we report a new and rapid synthetic route for a N-doped ordered mesoporous carbon structure through a preferential heating of iron oxide nanoparticles by microwaves. A nanoporous covalent organic polymer is first formed in situ covering the hard templates of assembled nanoparticles, paving the way for a long-range order in a carbonaceous nanocomposite precursor. Upon removal of the template, a well-defined cubic mesoporous carbon structure was revealed. The ordered mesoporous carbon was used in solid state hydrogen storage as a host scaffold for NaAlH4, where remarkable improvement in hydrogen desorption kinetics was observed. The state-of-the-art lowest activation energy of dehydrogenation as a single step was attributed to their ordered pore structure and N-doping effect.

The impact of nitrogen atoms on CO2 binding was evaluated for two isostructural porous bisimidazole-linked polymers (BILPs), which serendipitously had identical surface areas and pore size distributions, a very rare observation. The two structures differ only in the core of the trialdehyde component, the nitrogen atom (BILP-19) versus benzene ring (BILP-5). Such a slight difference, however, has brought about a stronger CO2 capture capacity of BILP-19 and hence increased CO2/N2 separation capability.

Lithium–sulfur (Li–S) batteries by far offer higher theoretical energy density than that of the commercial lithium-ion battery counterparts, but suffer predominantly from an irreversible shuttling ...

Adsorbed natural gas (ANG) technology is a viable alternative to conventional liquefied or compressed natural-gas storage. Many different porous materials have been considered for adsorptive, reversible methane storage, but fall short of the US Department of Energy targets (0.5 g g−1, 263 l l−1). Here, we prepare a flexible porous polymer, made from benzene and 1,2-dichloroethane in kilogram batches, that has a high methane working capacity of 0.625 g g−1 and 294 l l−1 when cycled between 5 and 100 bar pressure. We suggest that the flexibility provides rapid desorption and thermal management, while the hydrophobicity and the nature of the covalently bonded framework allow the material to tolerate harsh conditions. The polymer also shows an adsorbate memory effect, where a less adsorptive gas (N2) follows the isotherm profile of a high-capacity adsorbate (CO2), which is attributed to the thermal expansion caused by the adsorption enthalpy. The high methane capacity and memory effect make flexible porous polymers promising candidates for ANG technology. Adsorbing natural gas in porous materials is a potential storage alternative to conventional approaches based on liquefaction or compression, but higher capacities are required for commercial viability. Here, the authors employ porous covalent organic polymers that are flexible but robust, leading to high storage capacities and cyclability.

Nanoporous polymers offer great promise in chemical capture and separations because of their versatility, scalability, and robust nature. Here, we report a general methodology for one-pot, metal-free, and room-temperature synthesis of nanoporous polymers by highly stable carbon–carbon bond formation. Three new polymers, namely, COP-177, COP-178, and COP-179, are derived from widely available perfluoroarenes and found to be superhydrophobic, microporous, and highly stable against heat, acid, base, and organic solvents. Nitrile, amine, and ether functionalities were successfully installed by SNAr-type postfunctionalization and were shown to increase CO2 uptake twice and CO2/N2 selectivity 4-fold. Due to its inherent superhydrophobicity, COP-177 showed high organic solvent uptake both in liquid and vapor form. Furthermore, in a first of its kind, by combining microporosity and hydrophobicity, COP-177 separated two small molecules with the same boiling point in a continuous column setting.

Polypyrrole grafted polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene (SEBS-g-PPy)/multiwall carbon nanotubes (MWCNTs) conductive nanocomposites were fabricated using two different approaches...

Metal recovery from electronic waste and industrial wastewater has attracted increasing attention to recycle precious metals and inhibit the emission of hazardous heavy metals. However, the selective recovery of precious metals with a large quantity is still very challenging because wastewater contains a variety of different cations while precious metal ions are relatively scarce. Here, we introduce a simple method to selectively increase the adsorption of gold ions using tannin-coated porous polymer microspheres through photochemical reduction. Mesoporous poly(ethylene glycol dimethacrylate- co-acrylonitrile) microspheres with an average pore diameter of 13.8 nm were synthesized and used as an adsorbent matrix. Tannic acid (TA) was deposited onto the internal pores of the polymer matrix by simple immersion in an aqueous milieu. TA coatings increased the maximum number of adsorbed gold ions by 1.3 times because of the well-known metal ion chelation of TA. Under light illumination, the maximum number of adsorbed gold ions dramatically increased by 6.1 times. We examined two distinct mechanisms presumably involved in the enhanced adsorption: the photooxidation of TA and plasmon-induced hot electrons. Moreover, TA-coated microspheres exhibited remarkable selectivity for gold ions among competing metal ions commonly found in waste resources. This work suggests that the photochemically activated TA can serve as an excellent adsorbent for the selective and efficient recovery of gold ions from wastewater.

A new, high surface area, nanoporous polymer (COP-220) was synthesized using sustainable building blocks, namely, a food coloring dye (erythrosine B) and a commercial alkyne. During the Sonogashira coupling, it is observed that Pd and Cu ions and triphenylphosphine ligands of the catalyst get trapped inside the pores. The remnant synthesis catalyst components were characterized in detail and were tested as a new catalyst for Suzuki–Miyaura coupling reactions. COP-220 showed conversion yields comparable to the commercial homogeneous catalyst Pd(PPh3)2Cl2 with an additional advantage of size-dependent catalytic activity when bulkier substrates were used. COP-220 was highly stable under thermal and chemical treatments and recyclable with no loss of activity. These findings show a clear need for extensive characterization of nanoporous polymers made through cross-coupling reactions and the potential of the trapped catalysts for new catalytic activity without additional loading.

In this manuscript, we report synthesis, characterization and application of amine and amide type covalent organic frameworks as CO2 adsorbent materials at various isotherms and wide pressure conditions. Furthermore, we also report a detailed density functional theory investigation of the studied adsorbents in order to explain their adsorption behaviors and provide comparisons with experimental results. The objective of this work was to investigate custom design porous polymers by building amine and amide functionalities in the final structures, whether they have efficient CO2 capturing performances at wide process conditions that covers both low and high pressure end applications to cover either pre- or post-combustion processes. On the other hand, energy storage performances of these materials were tested by performing H2 sorption experiments as well. Two porous polymers, namely COP-9 and COP-10, were characterized with BET, TGA and FTIR to evaluate the physical properties of studied porous polymers and then were tested for CO2, N2 and H2 adsorption both at low and high pressures. Studied materials were found to have compelling adsorption capacity mostly at high pressures and have very good selectivity for CO2/N2 and CO2/H2 respectively.

Nanoporous materials could offer sustainable solutions to gas capture and precious metal recovery from electronic waste. Despite this potential, few reports combine target functionalities with physical properties such as morphology control. Here, we report a nanoporous polymer with microspherical morphology that could selectively capture gold from a mixture of 15 common transition metals. When its nitriles are converted into amidoxime, the capacity increases more than 20-fold. Amidoximes are also very effective in CO2 binding and show a record high CO2/CH4 selectivity of 24 for potential use in natural gas sweetening. The polymer is successfully synthesized in 1 kg batches starting from sustainable inexpensive building blocks without the need for costly catalysts. Because the morphology is controlled from the beginning, the nanoporous materials studied in lab scale could easily be moved into respective industries.

A structurally characterized novel dual-pocketed tetra-conjugated bisphenol-based chromophore (fluorescence = 652 nm) was synthesized in gram scale in ~90% yield from its tetraaldehyde. Highly selective, naked-eye detection of CN

Effective removal of excess greenhouse gas CO2 necessitates new adsorbents that can overcome the shortcomings of the current capture methods. To achieve that, porous materials are often modified post-synthetically with reactive amine functionalities but suffer from significant surface area losses. Herein, we report a successful amine post-functionalization of a highly porous covalent organic polymer, COP-130, without losing much porosity. By varying the amine substituents, we recorded a remarkable increase in CO2 uptake and selectivity. Ketone functionality, a rarely accessible functional group for porous polymers, was inserted prior to amination and led to covalent tethering of amines. Interestingly, aminated polymers demonstrated relatively low heats of adsorption, which is useful for the rapid recyclability of materials, due to the formation of suspected intramolecular hydrogen bonding.

Effective removal of excess greenhouse gas CO