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ZnN2F4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of four monofluoroamine molecules and two ZnF2 sheets oriented in the (0, 0, 1) direction. In each ZnF2 sheet, Zn2+ is bonded in a square co-planar geometry to four equivalent F1- atoms. All Zn–F bond lengths are 1.97 Å. F1- is bonded in a linear geometry to two equivalent Zn2+ atoms.
ZnGa2S4 crystallizes in the tetragonal P-42m space group. The structure is three-dimensional. Zn2+ is bonded to four equivalent S2- atoms to form ZnS4 tetrahedra that share corners with eight equivalent GaS4 tetrahedra. All Zn–S bond lengths are 2.36 Å. Ga3+ is bonded to four equivalent S2- atoms to form GaS4 tetrahedra that share corners with four equivalent ZnS4 tetrahedra and corners with four equivalent GaS4 tetrahedra. All Ga–S bond lengths are 2.32 Å. S2- is bonded in a trigonal non-coplanar geometry to one Zn2+ and two equivalent Ga3+ atoms.
ZnGa2S4 crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three ZnGa2S4 sheets oriented in the (0, 0, 1) direction. Zn2+ is bonded to six equivalent S2- atoms to form ZnS6 octahedra that share corners with six equivalent GaS4 tetrahedra and edges with six equivalent ZnS6 octahedra. All Zn–S bond lengths are 2.51 Å. Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with three equivalent ZnS6 octahedra and corners with six equivalent GaS4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are one shorter (2.21 Å) and three longer (2.38 Å) Ga–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a trigonal non-coplanar geometry to three equivalent Ga3+ atoms. In the second S2- site, S2- is bonded to three equivalent Zn2+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SZn3Ga trigonal pyramids.
ZnGa2S4 is Spinel structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Zn2+ is bonded to four equivalent S2- atoms to form ZnS4 tetrahedra that share corners with twelve equivalent GaS6 octahedra. The corner-sharing octahedral tilt angles are 58°. All Zn–S bond lengths are 2.36 Å. Ga3+ is bonded to six equivalent S2- atoms to form GaS6 octahedra that share corners with six equivalent ZnS4 tetrahedra and edges with six equivalent GaS6 octahedra. All Ga–S bond lengths are 2.47 Å. S2- is bonded to one Zn2+ and three equivalent Ga3+ atoms to form a mixture of distorted edge and corner-sharing SZnGa3 trigonal pyramids.
ZnGa2S4 crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. Zn2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (2.84 Å) and four longer (2.97 Å) Zn–S bond lengths. Ga3+ is bonded to four S2- atoms to form edge-sharing GaS4 tetrahedra. There are three shorter (2.30 Å) and one longer (2.35 Å) Ga–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent Zn2+ and two equivalent Ga3+ atoms. In the second S2- site, S2- is bonded to two equivalent Zn2+ and two equivalent Ga3+ atoms to form a mixture of distorted edge and corner-sharing SZn2Ga2 trigonal pyramids.
ZnO8N2(NO2)4 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four ammonia molecules; eight hydroxylamine, n-hydroxy- molecules; and two ZnO8 clusters. In each ZnO8 cluster, Zn2+ is bonded in a linear geometry to two equivalent O2- atoms. Both Zn–O bond lengths are 1.87 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Zn2+ and one O2- atom. The O–O bond length is 1.32 Å. In the second O2- site, O2- is bonded in a distorted water-like geometry to two O2- atoms. There is one shorter (1.21 Å) and one longer (1.72 Å) O–O bond length. In the third O2- site, O2- is bonded in a distorted water-like geometry to two O2- atoms. In the fourth O2- site, O2- is bonded in a single-bond geometry to one O2- atom.
ZnGa2S4 crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three ZnGa2S4 sheets oriented in the (0, 0, 1) direction. Zn2+ is bonded to four S2- atoms to form ZnS4 tetrahedra that share corners with three equivalent GaS6 octahedra and corners with six equivalent ZnS4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There are three shorter (2.25 Å) and one longer (2.62 Å) Zn–S bond lengths. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to six S2- atoms to form GaS6 octahedra that share corners with three equivalent ZnS4 tetrahedra, corners with three equivalent GaS4 tetrahedra, and edges with six equivalent GaS6 octahedra. There are three shorter (2.44 Å) and three longer (2.59 Å) Ga–S bond lengths. In the second Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with three equivalent GaS6 octahedra and corners with six equivalent GaS4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There are one shorter (2.27 Å) and three longer (2.36 Å) Ga–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a trigonal non-coplanar geometry to three equivalent Zn2+ atoms. In the second S2- site, S2- is bonded in a trigonal non-coplanar geometry to three equivalent Ga3+ atoms. In the third S2- site, S2- is bonded to one Zn2+ and three equivalent Ga3+ atoms to form corner-sharing SZnGa3 tetrahedra. In the fourth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to four Ga3+ atoms.
ZnGa2S4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Zn2+ is bonded to six S2- atoms to form ZnS6 octahedra that share corners with four equivalent ZnS6 octahedra, corners with four equivalent GaS6 octahedra, corners with four equivalent GaS4 tetrahedra, edges with two equivalent GaS6 octahedra, and an edgeedge with one GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–52°. There are a spread of Zn–S bond distances ranging from 2.51–2.67 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with two equivalent GaS6 octahedra, corners with four equivalent ZnS6 octahedra, an edgeedge with one ZnS6 octahedra, and edges with two equivalent GaS6 octahedra. The corner-sharing octahedra tilt angles range from 60–67°. There are a spread of Ga–S bond distances ranging from 2.26–2.31 Å. In the second Ga3+ site, Ga3+ is bonded to six S2- atoms to form GaS6 octahedra that share corners with four equivalent ZnS6 octahedra, corners with two equivalent GaS4 tetrahedra, edges with two equivalent ZnS6 octahedra, edges with two equivalent GaS6 octahedra, and edges with two equivalent GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–52°. There are a spread of Ga–S bond distances ranging from 2.48–2.52 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded to one Zn2+ and three Ga3+ atoms to form distorted corner-sharing SZnGa3 tetrahedra. In the second S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Zn2+ and three Ga3+ atoms. In the third S2- site, S2- is bonded in a rectangular see-saw-like geometry to two equivalent Zn2+ and two Ga3+ atoms.
ZnGa2S4 crystallizes in the hexagonal P6_3mc space group. The structure is two-dimensional and consists of two ZnGa2S4 sheets oriented in the (0, 0, 1) direction. Zn2+ is bonded to four S2- atoms to form ZnS4 tetrahedra that share corners with three equivalent GaS6 octahedra and corners with six equivalent ZnS4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There are three shorter (2.26 Å) and one longer (2.60 Å) Zn–S bond lengths. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to six S2- atoms to form GaS6 octahedra that share corners with three equivalent ZnS4 tetrahedra, corners with three equivalent GaS4 tetrahedra, and edges with six equivalent GaS6 octahedra. There are three shorter (2.45 Å) and three longer (2.59 Å) Ga–S bond lengths. In the second Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with three equivalent GaS6 octahedra and corners with six equivalent GaS4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There are one shorter (2.28 Å) and three longer (2.36 Å) Ga–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a trigonal non-coplanar geometry to three equivalent Ga3+ atoms. In the second S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to four Ga3+ atoms. In the third S2- site, S2- is bonded to one Zn2+ and three equivalent Ga3+ atoms to form corner-sharing SZnGa3 tetrahedra. In the fourth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three equivalent Zn2+ atoms.
Ag2ZnI4 crystallizes in the orthorhombic Pmn2_1 space group. The structure is three-dimensional. Ag1+ is bonded to four I1- atoms to form AgI4 tetrahedra that share corners with four equivalent AgI4 tetrahedra and corners with four equivalent ZnI4 tetrahedra. There are a spread of Ag–I bond distances ranging from 2.86–2.89 Å. Zn2+ is bonded to four I1- atoms to form ZnI4 tetrahedra that share corners with eight equivalent AgI4 tetrahedra. There are a spread of Zn–I bond distances ranging from 2.65–2.68 Å. There are three inequivalent I1- sites. In the first I1- site, I1- is bonded in a trigonal non-coplanar geometry to two equivalent Ag1+ and one Zn2+ atom. In the second I1- site, I1- is bonded in a trigonal non-coplanar geometry to two equivalent Ag1+ and one Zn2+ atom. In the third I1- site, I1- is bonded in a trigonal non-coplanar geometry to two equivalent Ag1+ and one Zn2+ atom.
ZnIr2O4 is Spinel structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Ir3+ is bonded to six equivalent O2- atoms to form IrO6 octahedra that share corners with six equivalent ZnO4 tetrahedra and edges with six equivalent IrO6 octahedra. All Ir–O bond lengths are 2.10 Å. Zn2+ is bonded to four equivalent O2- atoms to form ZnO4 tetrahedra that share corners with twelve equivalent IrO6 octahedra. The corner-sharing octahedral tilt angles are 58°. All Zn–O bond lengths are 2.05 Å. O2- is bonded to three equivalent Ir3+ and one Zn2+ atom to form a mixture of distorted edge and corner-sharing OZnIr3 trigonal pyramids.
(N2)Zn(Br)2 crystallizes in the orthorhombic Imma space group. The structure is zero-dimensional and consists of four diaminozinc molecules and eight hydrobromic acid molecules.
Electrochemical carbon dioxide (CO 2 ) reduction into value-added products holds great promise in moving toward carbon neutrality but remains a grand challenge due to lack of efficient electrocatalysts. Herein, the nucleophilic substitution reaction is elaborately harnessed to synthesize carbon nanoplates with a Fe-N 4 O configuration anchored onto graphene substrate (Fe-N 4 O-C/Gr) through covalent linkages. Density functional theory calculations demonstrate the unique configuration of Fe-N 4 O with one oxygen (O) atom in the axial direction not only suppresses the competing hydrogen evolution reaction, but also facilitates the desorption of *CO intermediate compared with the commonly planar single-atomic Fe sites. The Fe-N 4 O-C/Gr shows excellent performance in the electroreduction of CO 2 into carbon monoxide (CO) with an impressive Faradaic efficiency of 98.3% at -0.7 V versus reversible hydrogen electrode (RHE) and a high turnover frequency of 3511 h -1 . Furthermore, as a cathode catalyst in an aqueous zinc (Zn)-CO 2 battery, the Fe-N 4 O-C/Gr achieves a high CO Faradaic efficiency (≈91%) at a discharge current density of 3 mA cm -2 and long-term stability over 74 h. Here this work opens up a new route to simultaneously modulate the geometric and electronic structure of single-atomic catalysts toward efficient CO 2 conversion.
Zn-air battery (ZAB) is attracting increasing attention due to its high safety and performance. However, the practical application of ZAB relies heavily on developing durable support materials to replace conventional carbon supports which have unrecoverable corrosion issues, severely jeopardizing ZAB performance. Herein, a novel porous FeCo glassy alloy was developed as bifunctional catalytic support for ZAB. Specifically, the conducting skeleton of the porous glassy alloy was used to stabilize oxygen reduction cocatalysts, and more importantly, the FeCo served as the primary phase for oxygen evolution. To prove the concept of catalytic glassy alloy support, ultra-small Pd nanoparticles were anchored, as oxygen reduction active sites, on the porous FeCo (noted as Pd/FeCo) for ZAB. The Pd/FeCo exhibited a significantly improved electrocatalytic activity for oxygen reduction (a half-wave potential of 0.85 V) and oxygen evolution (a potential of 1.55 V to reach 10 mA cm –2 ) in the alkaline media. When used in the ZAB, the Pd/FeCo delivered an output power density of 117 mW cm –2 and outstanding cycling stability for over 200 h (400 cycles), surpassing the conventional carbon-supported Pt/C+IrO 2 catalysts. Such an integrated design of combining highly active components with porous architecture provides a new strategy to develop novel nanostructured electrocatalysts.
Abstract Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C 5+ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd‐promoted ZnO‐ZrO 2 catalyst. The sequence of reaction steps involved in the C 5+ ketone formation from ethanol was determined. The key reaction steps were found to be the in situ generation of the acetone intermediate and the cross‐aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of a Pd–Zn alloy in situ was identified to be the critical factor in maintaining high yield to the C 5+ ketones and the stability of the catalyst. A yield of >70 % to C 5+ ketones was achieved over a 0.1 % Pd‐ZnO‐ZrO 2 mixed oxide catalyst, and the catalyst was demonstrated to be stable beyond 2000 hours on stream without any catalyst deactivation.
Abstract Polymers are known to adsorb spontaneously from liquid solutions in contact with high‐energy substrates to form configurationally complex, but robust phases that often exhibit higher durability than might be expected from the individual physical bonds formed with the substrate. Rational control of the physical, chemical, and transport properties of such interphases has emerged as a fundamental opportunity for scientific and technological advances in energy storage technology but requires in‐depth understanding of the conformation states and electrochemical effect of the adsorbed polymers. Here, we analyze the interfacial adsorption of oligomeric polyethylene glycol (PEG) chains of moderate sizes dissolved in protic and aprotic liquid electrolytes and find that there is an optimum polymer molecular weight of approximately 400 Da at which the highest columbic efficiency is achieved for both Zn and Li deposition. These findings point to a simple, versatile approach for extending the lifetime of batteries.
Polymers are known to adsorb spontaneously from liquid solutions in contact with high-energy substrates to form configurationally complex, but robust phases that often exhibit higher durability than might be expected from the individual physical bonds formed with the substrate. Rational control of the physical, chemical, and transport properties of such interphases has emerged as a fundamental opportunity for scientific and technological advances in energy storage technology but requires in-depth understanding of the conformation states and electrochemical effect of the adsorbed polymers. Here, we analyze the interfacial adsorption of oligomeric polyethylene glycol (PEG) chains of moderate sizes dissolved in protic and aprotic liquid electrolytes and find that there is an optimum polymer molecular weight of approximately 400 Da at which the highest columbic efficiency is achieved for both Zn and Li deposition. Furthermore, these findings point to a simple, versatile approach for extending the lifetime of batteries.
Mixed-anion compounds widen the chemical space of attainable materials compared to single anionic compounds, but the exploration of their structural diversity is limited by common synthetic paths. Especially, oxychlorides rely mainly on layered structures, which suffer from low stability during photo(electro)catalytic processes. Herein we report a strategy to design a new polar 3D tetrahedral framework with composition Zn 4 Si 2 O 7 Cl 2 . We use a molten salt medium to enable low temperature crystallization of nanowires of this new compound, by relying on tetrahedral building units present in the melt to build the connectivity of the oxychloride. These units are combined with silicon-based connectors from a non-oxidic Zintl phase to enable precise tuning of the oxygen content. This structure brings high chemical and thermal stability, as well as strongly anisotropic hole mobility along the polar axis. These features, associated with the ability to adjust the transport properties by doping, enable to tune water splitting properties for photoelectrocatalytic H 2 evolution and water oxidation. This work then paves the way to a new family of mixed-anion solids