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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on YbB4Os by Materials Project

YbOsB4 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Yb2+ is bonded in a 2-coordinate geometry to four equivalent Os2- and fourteen B atoms. There are a spread of Yb–Os bond distances ranging from 3.02–3.10 Å. There are a spread of Yb–B bond distances ranging from 2.62–2.76 Å. Os2- is bonded in a 10-coordinate geometry to four equivalent Yb2+, one Os2-, and ten B atoms. The Os–Os bond length is 2.60 Å. There are a spread of Os–B bond distances ranging from 2.27–2.37 Å. There are four inequivalent B sites. In the first B site, B is bonded in a 3-coordinate geometry to four equivalent Yb2+, two equivalent Os2-, and three B atoms. There are a spread of B–B bond distances ranging from 1.75–1.85 Å. In the second B site, B is bonded in a 5-coordinate geometry to four equivalent Yb2+, two equivalent Os2-, and three B atoms. The B–B bond length is 1.84 Å. In the third B site, B is bonded in a 3-coordinate geometry to four equivalent Yb2+, two equivalent Os2-, and three B atoms. There is one shorter (1.74 Å) and one longer (1.77 Å) B–B bond length. In the fourth B site, B is bonded in a 9-coordinate geometry to two equivalent Yb2+, four equivalent Os2-, and three B atoms. The B–B bond length is 1.74 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zn3Os by Materials Project

OsZn3 is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Os is bonded to twelve Zn atoms to form OsZn12 cuboctahedra that share corners with four equivalent OsZn12 cuboctahedra, edges with eight equivalent OsZn12 cuboctahedra, edges with sixteen equivalent ZnZn8Os4 cuboctahedra, faces with four equivalent OsZn12 cuboctahedra, and faces with eight equivalent ZnZn8Os4 cuboctahedra. There are four shorter (2.61 Å) and eight longer (2.78 Å) Os–Zn bond lengths. There are two inequivalent Zn sites. In the first Zn site, Zn is bonded to four equivalent Os and eight Zn atoms to form distorted ZnZn8Os4 cuboctahedra that share corners with twelve equivalent ZnZn8Os4 cuboctahedra, edges with eight equivalent OsZn12 cuboctahedra, edges with eight equivalent ZnZn8Os4 cuboctahedra, faces with four equivalent OsZn12 cuboctahedra, and faces with ten equivalent ZnZn8Os4 cuboctahedra. There are four shorter (2.61 Å) and four longer (2.78 Å) Zn–Zn bond lengths. In the second Zn site, Zn is bonded in a square co-planar geometry to four equivalent Os and eight equivalent Zn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZrAsOs by Materials Project

ZrOsAs crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Zr4+ is bonded in a 11-coordinate geometry to six equivalent Os1- and five As3- atoms. There are two shorter (3.00 Å) and four longer (3.13 Å) Zr–Os bond lengths. There are one shorter (2.76 Å) and four longer (2.82 Å) Zr–As bond lengths. Os1- is bonded to six equivalent Zr4+, two equivalent Os1-, and four As3- atoms to form a mixture of distorted edge, face, and corner-sharing OsZr6As4Os2 cuboctahedra. Both Os–Os bond lengths are 2.80 Å. There are two shorter (2.55 Å) and two longer (2.58 Å) Os–As bond lengths. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded in a 9-coordinate geometry to six equivalent Zr4+ and three equivalent Os1- atoms. In the second As3- site, As3- is bonded in a 9-coordinate geometry to three equivalent Zr4+ and six equivalent Os1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Zn10Os)2 by Materials Project

UOs2Zn20 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to sixteen Zn atoms. There are four shorter (3.10 Å) and twelve longer (3.13 Å) U–Zn bond lengths. Os is bonded to twelve Zn atoms to form OsZn12 cuboctahedra that share corners with six equivalent OsZn12 cuboctahedra, edges with eighteen equivalent ZnUZn10Os cuboctahedra, and faces with six equivalent ZnUZn10Os cuboctahedra. There are six shorter (2.54 Å) and six longer (2.81 Å) Os–Zn bond lengths. There are three inequivalent Zn sites. In the first Zn site, Zn is bonded in a 2-coordinate geometry to two equivalent U and twelve equivalent Zn atoms. All Zn–Zn bond lengths are 3.04 Å. In the second Zn site, Zn is bonded in a distorted linear geometry to two equivalent Os and six equivalent Zn atoms. There are two shorter (2.69 Å) and four longer (2.83 Å) Zn–Zn bond lengths. In the third Zn site, Zn is bonded to one U, one Os, and ten Zn atoms to form distorted ZnUZn10Os cuboctahedra that share corners with fifteen equivalent ZnUZn10Os cuboctahedra, edges with two equivalent ZnUZn10Os cuboctahedra, edges with three equivalent OsZn12 cuboctahedra, a faceface with one OsZn12 cuboctahedra, and faces with fifteen equivalent ZnUZn10Os cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.64–2.92 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiPOs by Materials Project

TiOsP crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Ti4+ is bonded in a 11-coordinate geometry to six equivalent Os1- and five P3- atoms. There are two shorter (2.79 Å) and four longer (2.93 Å) Ti–Os bond lengths. There are one shorter (2.60 Å) and four longer (2.65 Å) Ti–P bond lengths. Os1- is bonded in a 12-coordinate geometry to six equivalent Ti4+, two equivalent Os1-, and four P3- atoms. Both Os–Os bond lengths are 2.74 Å. There are two shorter (2.38 Å) and two longer (2.44 Å) Os–P bond lengths. There are two inequivalent P3- sites. In the first P3- site, P3- is bonded in a 9-coordinate geometry to six equivalent Ti4+ and three equivalent Os1- atoms. In the second P3- site, P3- is bonded in a 9-coordinate geometry to three equivalent Ti4+ and six equivalent Os1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B3Os2 by Materials Project

Os2B3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Os+1.50- is bonded in a 7-coordinate geometry to seven B1+ atoms. There are four shorter (2.21 Å) and three longer (2.22 Å) Os–B bond lengths. There are two inequivalent B1+ sites. In the first B1+ site, B1+ is bonded in a distorted rectangular see-saw-like geometry to four equivalent Os+1.50- atoms. In the second B1+ site, B1+ is bonded to six equivalent Os+1.50- atoms to form distorted edge-sharing BOs6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H12OsSN4O7 by Materials Project

(OsH12(N2O)2)2(SO4)2O2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four sulfuric acid molecules, four water molecules, and four OsH12(N2O)2 clusters. In two of the OsH12(N2O)2 clusters, Os8+ is bonded in an octahedral geometry to four N1- and two equivalent O2- atoms. All Os–N bond lengths are 2.14 Å. Both Os–O bond lengths are 1.75 Å. There are two inequivalent N1- sites. In the first N1- site, N1- is bonded in a trigonal non-coplanar geometry to one Os8+ and three H1+ atoms. There is one shorter (1.03 Å) and two longer (1.04 Å) N–H bond length. In the second N1- site, N1- is bonded in a trigonal non-coplanar geometry to one Os8+ and three H1+ atoms. There is two shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. O2- is bonded in a single-bond geometry to one Os8+ atom. In two of the OsH12(N2O)2 clusters, Os8+ is bonded in an octahedral geometry to four N1- and two equivalent O2- atoms. All Os–N bond lengths are 2.14 Å. Both Os–O bond lengths are 1.75 Å. There are two inequivalent N1- sites. In the first N1- site, N1- is bonded in a trigonal non-coplanar geometry to one Os8+ and three H1+ atoms. There is two shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. In the second N1- site, N1- is bonded in a trigonal non-coplanar geometry to one Os8+ and three H1+ atoms. There is two shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. O2- is bonded in a single-bond geometry to one Os8+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KOsNO3 by Materials Project

KOsNO3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to two N3- and six O2- atoms. There are one shorter (2.96 Å) and one longer (3.02 Å) K–N bond lengths. There are a spread of K–O bond distances ranging from 2.89–2.98 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to two N3- and six O2- atoms. There are one shorter (2.94 Å) and one longer (3.03 Å) K–N bond lengths. There are a spread of K–O bond distances ranging from 2.90–2.97 Å. There are two inequivalent Os8+ sites. In the first Os8+ site, Os8+ is bonded in a tetrahedral geometry to one N3- and three O2- atoms. The Os–N bond length is 1.70 Å. There is one shorter (1.76 Å) and two longer (1.77 Å) Os–O bond length. In the second Os8+ site, Os8+ is bonded in a tetrahedral geometry to one N3- and three O2- atoms. The Os–N bond length is 1.71 Å. There is one shorter (1.76 Å) and two longer (1.77 Å) Os–O bond length. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted single-bond geometry to two K1+ and one Os8+ atom. In the second N3- site, N3- is bonded in a distorted single-bond geometry to two K1+ and one Os8+ atom. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one Os8+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one Os8+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one Os8+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one Os8+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one Os8+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one Os8+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZrPOs by Materials Project

ZrOsP crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Zr4+ is bonded in a 11-coordinate geometry to six equivalent Os1- and five P3- atoms. There are two shorter (2.92 Å) and four longer (3.04 Å) Zr–Os bond lengths. There are one shorter (2.69 Å) and four longer (2.75 Å) Zr–P bond lengths. Os1- is bonded to six equivalent Zr4+, two equivalent Os1-, and four P3- atoms to form a mixture of distorted corner, edge, and face-sharing OsZr6P4Os2 cuboctahedra. Both Os–Os bond lengths are 2.76 Å. There are two shorter (2.48 Å) and two longer (2.51 Å) Os–P bond lengths. There are two inequivalent P3- sites. In the first P3- site, P3- is bonded in a 9-coordinate geometry to six equivalent Zr4+ and three equivalent Os1- atoms. In the second P3- site, P3- is bonded in a 3-coordinate geometry to three equivalent Zr4+ and six equivalent Os1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfAsOs by Materials Project

HfOsAs crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Hf4+ is bonded in a 11-coordinate geometry to six equivalent Os1- and five As3- atoms. There are two shorter (2.97 Å) and four longer (3.12 Å) Hf–Os bond lengths. There are one shorter (2.77 Å) and four longer (2.80 Å) Hf–As bond lengths. Os1- is bonded to six equivalent Hf4+, two equivalent Os1-, and four As3- atoms to form a mixture of distorted edge, face, and corner-sharing OsHf6As4Os2 cuboctahedra. Both Os–Os bond lengths are 2.82 Å. There are two shorter (2.53 Å) and two longer (2.57 Å) Os–As bond lengths. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded in a 9-coordinate geometry to six equivalent Hf4+ and three equivalent Os1- atoms. In the second As3- site, As3- is bonded in a 9-coordinate geometry to three equivalent Hf4+ and six equivalent Os1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on OsRu by Materials Project

Ru(Os) crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Os2- is bonded to six equivalent Os2- and six equivalent Ru2+ atoms to form a mixture of face, edge, and corner-sharing OsOs6Ru6 cuboctahedra. All Os–Os bond lengths are 2.74 Å. All Os–Ru bond lengths are 2.69 Å. Ru2+ is bonded in a 6-coordinate geometry to six equivalent Os2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Co3Os by Materials Project

OsCo3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Os is bonded to twelve Co atoms to form OsCo12 cuboctahedra that share corners with four equivalent OsCo12 cuboctahedra, corners with eight equivalent CoCo8Os4 cuboctahedra, edges with eight equivalent OsCo12 cuboctahedra, edges with sixteen equivalent CoCo8Os4 cuboctahedra, faces with four equivalent OsCo12 cuboctahedra, and faces with fourteen CoCo8Os4 cuboctahedra. There are eight shorter (2.52 Å) and four longer (2.53 Å) Os–Co bond lengths. There are two inequivalent Co sites. In the first Co site, Co is bonded to four equivalent Os and eight Co atoms to form CoCo8Os4 cuboctahedra that share corners with twelve equivalent CoCo8Os4 cuboctahedra, edges with eight equivalent OsCo12 cuboctahedra, edges with sixteen CoCo8Os4 cuboctahedra, faces with four equivalent OsCo12 cuboctahedra, and faces with fourteen CoCo8Os4 cuboctahedra. There are four shorter (2.52 Å) and four longer (2.53 Å) Co–Co bond lengths. In the second Co site, Co is bonded to four equivalent Os and eight equivalent Co atoms to form CoCo8Os4 cuboctahedra that share corners with four equivalent CoCo8Os4 cuboctahedra, corners with eight equivalent OsCo12 cuboctahedra, edges with twenty-four CoCo8Os4 cuboctahedra, faces with six equivalent OsCo12 cuboctahedra, and faces with twelve CoCo8Os4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfPOs by Materials Project

HfOsP crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Hf4+ is bonded in a 11-coordinate geometry to six equivalent Os1- and five P3- atoms. There are two shorter (2.89 Å) and four longer (3.02 Å) Hf–Os bond lengths. There are one shorter (2.67 Å) and four longer (2.73 Å) Hf–P bond lengths. Os1- is bonded to six equivalent Hf4+, two equivalent Os1-, and four P3- atoms to form a mixture of distorted edge, corner, and face-sharing OsHf6P4Os2 cuboctahedra. Both Os–Os bond lengths are 2.76 Å. There are two shorter (2.46 Å) and two longer (2.50 Å) Os–P bond lengths. There are two inequivalent P3- sites. In the first P3- site, P3- is bonded in a 9-coordinate geometry to six equivalent Hf4+ and three equivalent Os1- atoms. In the second P3- site, P3- is bonded in a 3-coordinate geometry to three equivalent Hf4+ and six equivalent Os1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on OsSeS3Cl4 by Materials Project

OsSeS3Cl4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are two inequivalent Os6+ sites. In the first Os6+ site, Os6+ is bonded to three S2- and three Cl1- atoms to form edge-sharing OsS3Cl3 octahedra. There are a spread of Os–S bond distances ranging from 2.24–2.29 Å. There are a spread of Os–Cl bond distances ranging from 2.40–2.44 Å. In the second Os6+ site, Os6+ is bonded to three S2- and two Cl1- atoms to form edge-sharing OsS3Cl2 square pyramids. There are one shorter (2.24 Å) and two longer (2.27 Å) Os–S bond lengths. There are one shorter (2.42 Å) and one longer (2.46 Å) Os–Cl bond lengths. There are two inequivalent Se4+ sites. In the first Se4+ site, Se4+ is bonded in a distorted rectangular see-saw-like geometry to four Cl1- atoms. There are a spread of Se–Cl bond distances ranging from 2.20–2.84 Å. In the second Se4+ site, Se4+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Se–S bond distances ranging from 2.24–2.61 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 6-coordinate geometry to one Se4+, one S2-, and four Cl1- atoms. The S–S bond length is 2.04 Å. There are a spread of S–Cl bond distances ranging from 3.41–3.80 Å. In the second S2- site, S2- is bonded in a 2-coordinate geometry to one Se4+ and one S2- atom. The S–S bond length is 2.03 Å. In the third S2- site, S2- is bonded in a 1-coordinate geometry to one Os6+ and one S2- atom. In the fourth S2- site, S2- is bonded in a 3-coordinate geometry to two Os6+ and one Cl1- atom. The S–Cl bond length is 2.08 Å. In the fifth S2- site, S2- is bonded in a 1-coordinate geometry to one Os6+ and one S2- atom. In the sixth S2- site, S2- is bonded in a 2-coordinate geometry to two Os6+ and one Se4+ atom. There are eight inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one Os6+ and one Se4+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Os6+ and one S2- atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Os6+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Os6+ atom. In the fifth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to two S2- atoms. In the sixth Cl1- site, Cl1- is bonded in a single-bond geometry to one Se4+ and one S2- atom. In the seventh Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one Os6+, one Se4+, and one S2- atom. In the eighth Cl1- site, Cl1- is bonded in a single-bond geometry to one Se4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Highly Efficient Organosulfur and Lithium‐Metal Hosts Enabled by C@Fe 3 N Sponge

Abstract Lithium‐organosulfur (Li‐OS) batteries, despite possessing high theoretical specific capacity, encounter a few practical challenges, including unsatisfactory lifespan and low active material utilization under realistic conditions. Here, diisoropyl xanthogen polysulfide (DIXPS) has been selected as a model organosulfur compound to investigate the practical feasibility of Li‐OS batteries under realistic conditions. A well‐designed freestanding carbon sponge decorated with Fe 3 N nanoparticles (C@Fe 3 N) is introduced into the Li‐OS cells as a scaffold for both Li and DIXPS. The lithiophilic property of the C@Fe 3 N host guides uniform lithium deposition at the anode, and the catalysis of the DIXPS conversion reaction promotes the kinetics at the cathode. Impressively, the synergistic effect of C@Fe 3 N leads to an extremely stable cycling performance over 1 000 cycles in a Li‐OS full cell under realistic conditions.

He, Jiarui↗
DOE OSTI2022

Highly Efficient Organosulfur and Lithium-Metal Hosts Enabled by C@Fe 3 N Sponge

Lithium-organosulfur (Li-OS) batteries, despite possessing high theoretical specific capacity, encounter a few practical challenges, including unsatisfactory lifespan and low active material utilization under realistic conditions. Here, diisoropyl xanthogen polysulfide (DIXPS) has been selected as a model organosulfur compound to investigate the practical feasibility of Li-OS batteries under realistic conditions. A well-designed freestanding carbon sponge decorated with Fe 3 N nanoparticles (C@Fe 3 N) is introduced into the Li-OS cells as a scaffold for both Li and DIXPS. The lithiophilic property of the C@Fe 3 N host guides uniform lithium deposition at the anode, and the catalysis of the DIXPS conversion reaction promotes the kinetics at the cathode. Impressively, the synergistic effect of C@Fe 3 N leads to an extremely stable cycling performance over 1000 cycles in a Li-OS full cell under realistic conditions.

25 ENERGY STORAGE↗
DOE OSTI2020

Facing the Challenges of Borderline Oxidation State Assignments Using State-of-the-Art Computational Methods.

The oxidation state (OS) of metals and ligands in inorganic complexes may be defined by carefully curated rules, such as from IUPAC, or by computational procedures such as the effective oxidation state (EOS) or localized orbital bonding analysis (LOBA). Such definitions typically agree for systems with simple ionic bonding and innocent ligands but may disagree as the boundary between ionic and covalent bonds is approached, or as the role of ligand noninnocence becomes nontrivial, or high oxidation states of metals are supported by heavy dative bonding, and so on. This work systematically compares IUPAC, EOS, and LOBA across a series of complexes where OS assignment is challenging. These systems include high-valent transition metal oxides, transition metal complexes with noninnocent ligands such as dithiolate and nitrosyl, metal sulfur dioxide adducts, and two transition metal carbene complexes. The differences in OS assignment by the three methods are carefully discussed, demonstrating the synergy between EOS and LOBA. In addition, a clarity index for LOBA OS assignments is introduced that provides an indication of whether or not its predictions are close to the ionic-covalent boundary.

Gimferrer, Martí↗
DOE OSTI2022

Specific Ion and Electric Field Controlled Diverse Ion Distribution and Electroosmotic Transport in a Polyelectrolyte Brush Grafted Nanochannel

Controlling ion distribution inside a charged nanochannel is central to using such channels in diverse applications. Here, we show the possibility of using a charged polyelectrolyte (PE) brush grafted nanochannel for triggering diverse nanoscopic ion distribution and nanofluidic electroosmotic transport by controlling the valence and size of the counterions (that screen the charges of the PE brushes) and the strength of an externally applied axial electric field. We atomistically simulate separate cases of fully charged Polyacrylic acid (PAA) brush functionalized nanochannels with Na + , Cs + , Ca 2+ , Ba 2+ , and Y 3+ counterions screening the PE charges. Four key findings emerge from our simulations. First, we find that the counterions with a greater valence and a smaller size prefer to remain localized inside the brush layer. Second, for the case where there is an added chloride salt with the same cation (as the screening counterions), there are more coions (Cl - ions) in the brush-free bulk than counterions (for counterions Na + , Ca 2+ , Ba 2+ , Y 3+ ): this is a manifestation of the overscreening (OS) of the PE brush layer. Contrastingly, the number of Cs + ions remain higher than the Cl - ions inside the brush-free bulk, ensuring that there is no OS effect for this case. Third, large applied electric field enables a few Na + , Cs + , and Ba 2+ counterions to leave the brush layer and to go to the bulk: this makes the OS of the PE brush layer disappear for the cases of PE brushes being screened by the Na+ and Ba 2+ ions. On the other hand, no such electric-field-mediated disappearance of OS is observed for the cases of Ca 2+ and Y 3+ screening counterions; we attribute this to the firm attachment of these counterions to the negatively charged monomers. Free energy associated to a counterion binding to a PE chain corroborates this diversity in the counterion-specific response to the applied electric field. Lastly, we demonstrate that such diverse ion distributions, along with specific electric-field-strength-dependent ion properties, lead to (1) EOS transport in nanochannels grafted with PAA brushes screened with Cs + ions to be always counterion dominated, (2) EOS transport in nanochannels grafted with PAA brushes screened with Ca 2+ and Y 3+ ions to be always coion dominated, and (3) EOS transport in nanochannels grafted with PAA brushes screened with Na + and Ba 2+ ions to be coion dominated for smaller electric fields and counterion dominated for larger electric fields.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗