2020 New's Items

Size Transformation of the Au22(SG)18 Nanocluster and Its Surface-Sensitive Kinetics

Zhang B
Chen C
Chuang W
Chen S
Yang P
2020

For many applications of well-defined gold nanoclusters, it is desirable to understand their structural evolution behavior under working conditions with molecular precision. Here we report the first systematic investigation of the size transformation products of the Au22(SG)18 nanocluster under representative working conditions and highlight the surface effect on the transformation kinetics. Under thermal and aerobic conditions, the consecutive and pH-dependent transformation from Au22 to both well-defined...

Direct Correlation of Single-Particle Motion to Amorphous Microstructural Components of Semicrystalline Poly(ethylene oxide) Electrolytic Films

Roberts TD
Yuan R
Xiang L
Delor M
Pokhrel R
Yang K
Aqad E
Marangoni T
Trefonas P
Xu K
Ginsberg NS
2020

Semicrystalline polymers constitute some of the most widely used materials in the world, and their functional properties are intimately connected to their structure on a range of length scales. Many of these properties depend on the micro- and nanoscale heterogeneous distribution of crystalline and amorphous phases, but this renders the interpretation of ensemble averaged measurements challenging. We use superlocalized widefield single-particle tracking in conjunction with AFM phase imaging to correlate the crystalline morphology of lithium-triflate-doped poly(ethylene oxide) thin...

Energy storage emerging: A perspective from the Joint Center for Energy Storage Research

Trahey L
Brushett FR
Balsara NP
Ceder G
Cheng L
Chiang Y-M
Hahn NT
Ingram BJ
Minteer SD
Moore JS
Mueller KT
Nazar LF
Persson KA
Siegel DJ
Xu K
Zavadil KR
Srinivasan V
Crabtree GW
2020

Energy storage is an integral part of modern society. A contemporary example is the lithium (Li)-ion battery, which enabled the launch of the personal electronics revolution in 1991 and the first commercial electric vehicles in 2010. Most recently, Li-ion batteries have expanded into the electricity grid to firm variable renewable generation, increasing the efficiency and effectiveness of transmission and distribution. Important applications continue to emerge including decarbonization of heavy-duty vehicles, rail, maritime shipping, and aviation and the growth of renewable...

Single-Molecule Studies of Protein Folding with Optical Tweezers

Bustamante C
Alexander L
Maciuba K
Kaiser CM
2020

Manipulation of individual molecules with optical tweezers provides a powerful means of interrogating the structure and folding of proteins. Mechanical force is not only a relevant quantity in cellular protein folding and function, but also a convenient parameter for biophysical folding studies. Optical tweezers offer precise control in the force range relevant for protein folding and unfolding, from which single-molecule kinetic and thermodynamic information about these processes can be extracted. In this review, we describe both physical principles and practical aspects of optical...

A Review on Challenges and Successes in Atomic-Scale Design of Catalysts for Electrochemical Synthesis of Hydrogen Peroxide

Siahrostami S
Villegas SJ
Bagherzadeh Mostaghimi AH
Back S
Farimani AB
Persson KA
Montoya J
Wang H
2020

Hydrogen peroxide is a valuable chemical oxidant with a wide range of applications in a variety of industrial processes, especially in water sanitization. Electrochemical synthesis of hydrogen peroxide (H2O2) through a two-electron oxygen reduction reaction (2e-ORR) or a two-electron water oxidation reaction (2e-WOR) has emerged as an appealing process for onsite production of this chemically valuable oxidant. On-site produced H2O2 can be applied for wastewater treatment in remote...

Anisotropic 2D excitons unveiled in organic–inorganic quantum wells

L. Maserati
S. Refaely-Abramson
C. Kastl
C. T. Chen
N. J. Borys
C. N. Eisler
M. S. Collins
T. E. Smidt
E. S. Barnard
M. Strasbourg
E. A. Schriber
B. Shevitski
K. Yao
J. N. Hohman
P. J. Schuck
S. Aloni
J. B. Neaton
A. N. Schwartzberg
2020

Two-dimensional (2D) excitons arise from electron–hole confinement along one spatial dimension. Such excitations are often described in terms of Frenkel or Wannier limits according to the degree of exciton spatial localization and the surrounding dielectric environment. In hybrid material systems, such as the 2D perovskites, the complex underlying interactions lead to excitons of an intermediate nature, whose description lies somewhere between the two limits, and a better physical description is needed. Here, we explore the photophysics of a tuneable materials platform where...

NMR Studies of Block Copolymer-Based Supramolecules in Solution

Chang BS
Ma L
He M
Xu T
2020

Hierarchical assemblies from block copolymer (BCP)-based supramolecules have shown immense potential as programmable materials owing to their versatility for incorporating functional molecules and provide access to arrays of hierarchical structures. However, there remains a knowledge gap on the formation of the supramolecule in solution. Here, we applied NMR techniques to investigate the solution-phase behavior of the most studied supramolecular systems, polystyrene-block-poly(4-vinylpyridine)(3-pentadecylphenol) (PS-b-P4VP(PDP)r)....

Cooperative carbon capture and steam regeneration with tetraamine-appended metal-organic frameworks

E. J. Kim
R. L. Siegelman
H. Z. H. Jiang
A. C. Forse
J.-H. Lee
J. D. Martell
P. J. Milner
J. M. Falkowski
J. B. Neaton
J. A. Reimer
S. C. Weston
J. R. Long
2020

Natural gas has become the dominant source of electricity in the United States, and technologies capable of efficiently removing carbon dioxide (CO2) from the flue emissions of natural gas-fired power plants could reduce their carbon intensity. However, given the low partial pressure of CO2 in the flue stream, separation of CO2 is particularly challenging. Taking inspiration from the crystal structures of diamine-appended metal-organic frameworks exhibiting two-step cooperative CO2...

Probing calcium solvation by XAS, MD and DFT calculations

Yang F
Liu Y-S
Feng X
Qian K
Kao LC
Ha Y
Hahn N
Seguin TJ
Tsige M
Yang W
Zavadil K
Persson KA
Guo J
2020

The solvation shell structures of Ca2+ in aqueous and organic solutions probed by calcium L-edge soft X-ray absorption spectroscopy (XAS) and DFT/MD simulations show the coordination number of Ca2+ to be negatively correlated with the electrolyte concentration and the steric hindrance of the solvent molecule. In this work, the calcium L-edge soft XAS demonstrates its sensitivity to the surrounding chemical environment. Additionally, the total electron yield (TEY) mode is surface sensitive because the...

Standard Practices of Reticular Chemistry

Gropp C
Canossa S
Wuttke S
Gándara F
Li Q
Gagliardi L
Yaghi OM
2020

Since 1995 when the first of metal−organic frameworks was crystallized with the strong bond approach, where metal ions are joined by charged organic linkers exemplified by carboxylates, followed by proof of their porosity in 1998 and ultrahigh porosity in 1999, a revolution in the development of their chemistry has ensued. This is being reinforced by the discovery of two- and three-dimensional covalent organic frameworks in 2005 and 2007. Currently, the chemistry of such porous, crystalline frameworks is collectively referred to as reticular chemistry, which is being practiced in...