Molybdenum disulfide is a sulfur-tolerant candidate for the water gas shift (WGS) reaction, but its performance is often limited by insufficient exposure and stability of edge sites. This study explores the role of silicalite-1 (S-1), an inert, purely siliceous MFI zeolite, in promoting MoS2 dispersion and increasing the density of accessible edge sites, thereby enhancing catalytic performance in the WGS reaction. Furthermore, it demonstrates that selenium modification of MoS2 further amplifies these support-induced effects. Samples were prepared by impregnation with a Mo precursor for MoS2/S-1 and with Mo and Se precursors for MoS1.75Se0.25/S-1 followed by sulfidation, yielding highly dispersed few-layer MoS2-derived domains on the silicalite-1 support. Raman spectroscopy indicates that Se incorporation promotes a mixed 1T '/2H phase compared to predominantly 2H MoS2 on silicalite-1 support. In situ (H2O)-O-18 adsorption FTIR measurements indicate enhanced water affinity for the MoS1.75Se0.25/S-1 sample. Under continuous-flow WGS (250-450 degrees C), supported catalysts strongly outperform bulk analogues. The MoS1.75Se0.25/S-1 sample exhibited the highest cumulative amount of CO converted of 54, 98, and 143 mmol g(-1) after 12 h on stream at 250, 350, and 450 degrees C, respectively, highlighting the beneficial combination of zeolite-enabled dispersion and Se-driven electronic/phase modification under WGS conditions.

Abstract Copper-rich sulfides have emerged in the past decade as serious candidates for cost-efficient and environmentally friendly thermoelectric applications. In the present work, we succeeded in introducing Fe3+ (d5 electronic configuration) into interstitial sites within the sphalerite framework, typically occupied by d0 cations, to create germanite-inspired colusite-type structures. The Cu26-xFe2+xGe6S32 (0 ≤ x ≤ 4) series retains the parent cubic symmetry characteristic of both colusite and germanite, while progressively approaching the Fe-rich cation distribution of synthetic germanite Cu22Fe8Ge4S32. High-resolution X-ray diffraction and transmission electron microscopy show that the cubic sphalerite-derived framework (space group P4̅3n) is preserved, while increasing Fe content induces controlled disorder on the mixed Cu/Fe 12f site. 57Fe Mössbauer spectroscopy confirms the oxidation state of Fe3+ cations and their preferred occupation at both the interstitial 2a site and the surrounding 12f position, generating a wide distribution of local environments arising from the mixed occupancy in [FeS4](Cu,Fe)6 tetrahedral–octahedral complexes. First-principles calculations based on density functional theory confirm the preferred substitution of Cu by Fe on the 12f site, as well as a favored Fe clustering in Cu26-xFe2+xGe6S32 for high x values. This engineered disorder markedly reduces the lattice thermal conductivity from 3.2 W m–1 K–1 (x = 0) to 1.4 W m–1 K–1 (x = 4) at room temperature, while the concomitant tuning of the Cu2+/Cu+ ratio optimizes carrier concentration and Seebeck coefficient, leading to a peak zT of 0.42 at 673 K for x = 3. Magnetic measurements reveal soft ferromagnetic-like behavior and unusually low effective moments, pointing to strong Fe–S hybridization and intersite interactions. This work demonstrates that Fe3+ (d5 cation) can occupy interstitial sites and induce mixed occupancy within the sphalerite-derived network, revealing a strategy for coupling controlled structural disorder, phonon scattering, and carrier transport in copper-rich sulfide thermoelectrics.

Lyotropic chromonic liquid crystals (LCLC) enable the templating of silica fibers with aligned porous structures and tunable pore size, properties that hold significant potential for applications like controlled drug delivery. LCLC guide the synthesis of microporous and mesoporous silicas through sol-gel reactions in the presence of silicon alkoxides, such as tetraethyl orthosilicate (TEOS), typically producing fibers with long, aligned pores and specific surface areas around 200-300 m2/g. Here, we develop micro/mesoporous silica materials using a cationic chromonic perylene diimide as template, combined with a porogenic silica precursor, hexadecyl trimethoxysilane (HDTMS), to achieve increased specific surface areas and larger pore sizes compared to conventional TEOS-based chromonic-templated silicas. The resulting silica materials can be fabricated as macroscopic, centimeter-sized monoliths with tunable porosity, composed of entangled silica nanofibers forming a networked structure. These highly porous monoliths were evaluated as carriers of small drugs (ibuprofen), and demonstrated high encapsulation efficiencies, as well as sustained drug release in a simulated body fluid (SBF, pH = 7.4), achieving complete release within 24 h. In contrast, powdered silica samples of the same composition showed poorer encapsulation efficiencies and faster release rates, highlighting the advantages of monolithic structures for drug delivery. Furthermore, hydroxyapatite (HAp) was deposited onto the silica monoliths to produce robust composite scaffolds, whose degradation products did not affect HEK293 cell viability.

The preparation of a Ni-embedded Beta zeolite catalyst (Ni-PS-BEA) via the in situ transformation of nickel phyllosilicate (Ni-PS) is reported. The nickel phyllosilicate is synthesized with a sheet-like morphology that aligns well with the structure of zeolite BEA. This approach, distinct from conventional impregnation, promotes the formation of octahedrally coordinated Ni2+ species covalently bound to the zeolite framework through Al-O-Ni-O-Si linkages, yielding highly dispersed NiO6 units that interact intimately with the lattice rather than forming isolated nickel oxides. The exceptional thermal stability of Ni-PS-BEA is attributed to Al-O-Ni bond formation, which simultaneously stabilizes framework aluminum and suppresses Ni leaching. Embedding within the framework also renders Ni more resistant to reduction compared to the conventionally impregnated sample (Ni/BEA), resulting in a more finely dispersed metallic phase. In dry reforming of methane (DRM), the Ni-PS-BEA sample exhibits markedly enhanced catalytic activity, achieving 33% CH4 conversion at 600 degrees C, compared to only 3% for Ni/BEA.

In this study, the epitaxial growth of nickel titanate NiTiO3 thin films on sapphire substrates is investigated, with a focus on stabilizing a LiNbO3-like structure. The films were deposited under controlled conditions using reactive radio-frequency sputtering, and their structural properties were characterized using X-ray diffraction as well as scanning and transmission electron microscopy. The results indicate that the substrate plays a crucial role in determining their orientation. On (0 0 1) sapphire, the films predominantly adopt a (0 0 l) orientation, although a secondary (1 0 4) orientation appears in thicker films. In contrast, on (1 0 0) sapphire substrates, the films exhibit a (1 0 0) orientation. Most importantly, the films stabilize in a non-centrosymmetric structure-specifically the LiNbO3-like phase-particularly at intermediate thicknesses (80-120 nm). This phase stabilization is driven by the epitaxial strain induced by the sapphire substrate.

Guided by high-temperature in situ X-ray diffraction, the discovery and synthesis of Mg1+εCo4B4 (ε ≈ 0.272) using a MgH2 hydride precursor is reported, along with a detailed crystal structure description and measurement of magnetic properties. The mismatch in lattice periodicities between Mg and Co-B substructures places Mg1+εCo4B4 in the family of incommensurate composite crystals and prompted structural refinement in a (3 + 1)-dimensional model. The structure of Mg1+εCo4B4 (P42/ncm(00γ)s00s, a = 6.75847(7) Å, c = 3.94007(8) Å, q = (0, 0, 1.2721(3))) was refined from neutron powder diffraction and high-resolution powder X-ray diffraction data and confirmed by scanning transmission electron microscopy and electron diffraction. Mg1+εCo4B4 is isostructural to Nd1+εFe4B4 and several related ternary borides with 0.07 ≤ ε ≤ 0.17, with Mg occupying the rare-earth site. Satellite reflections in the electron diffraction patterns hinted at positional modulation of the transition metal-boron substructure by Mg atoms, but this could not be refined from the neutron or X-ray diffraction data. Low-temperature magnetic measurements show no indications of long-range magnetic ordering or superconductivity down to 5 K. DFT calculations confirmed the absence of a magnetically ordered ground state and the stability of a 5:4 supercell (ε = 0.25) relative to the fully commensurate structure. Neutron diffraction and synthesis from elemental Mg demonstrated that Mg1+εCo4B4 is not a hydrogen-stabilized phase. Mg1+εCo4B4 represents the second compound reported in the Mg-Co-B system and the first superspace symmetry model of a Nd1+εFe4B4-type incommensurate composite compound refined from powder diffraction data.

Herein, we report a strategy for preparing polymer brushes of single-atom-based photocatalysts on the external surface of zeolite particles. The hybrid photocatalyst was prepared via the "on-surface" photopolymerization process of [2,2 '-bipyridine]-4,4 '-diyl diacrylate monomers (A2bpy) on a zeolite X (ZX) surface, postfunctionalized with a photoinitiator, and dispersed in the monomers solution. The polymer brush formed on the outer surface of the zeolite particles was successfully cofunctionalized with Ru(bpy)3Cl2 and/or Re(bpy)(CO)3Cl, serving as the benchmark photosensitizer and photocatalyst, respectively. This process yielded a core-shell-like zeolite structure surrounded by a poly single-atom-based photocatalyst. The quantitative analyses of various samples, through advanced analytical techniques, demonstrate high yields of both ligand photopolymerization (>65%) and postbipyridine functionalization (>45%). The accessibility of the pores of the zeolite core is well preserved after both polymerization and complexation processes, facilitating reactant (e.g., H2O, CO2, HCO3 -) absorption and release. Absorption transient spectroscopy confirmed efficient Ru-Re charge transfer. The hybrid photocatalysts demonstrated a 5-fold increase in activity compared to the pure polymer counterpart (poly[Re]). This enhanced performance is attributed to the affinity of the zeolite pores for CO2/carbonate adsorption and improved active sites accessibility. This study presents a cost-effective strategy for synthesizing versatile, recyclable materials and catalysts with potential applications in catalysis, 3D-printed nano-objects, multimetal assembled catalysts, mixed-matrix integrated membranes, and the immobilization of poly(bpy) on solid supports for medical and (photo)catalytic purposes.

The ternary transition-metal cyanamide MnCr2(NCN)4 was synthesized by a solid-state metathesis reaction between MnCl2, CrCl3, and ZnNCN. Powder X-ray diffraction reveals that MnCr2(NCN)4 adopts an orthorhombic [NiAs]-derived structure with Pbcn symmetry, featuring a hexagonally close-packed array of NCN2- with metal cations in 3/4 of the octahedral interstitial holes. The question of cation order was addressed via the combinatorial use of X-ray powder diffraction, neutron powder diffraction, electron diffraction, and HAADF-STEM measurements. These studies support an average structure with complete ordering of Mn2+ and Cr3+ in single and double corrugated rows of like cations, respectively. HAADF images, however, suggest locally a degree of cation disorder, especially at the manganese site. UV-vis and XANES measurements confirm the assignment of divalent manganese and trivalent chromium, whereas IR spectroscopy reveals the presence of cyanamide-type NCN2- moieties with a degree of single and triple bond character due to the asymmetric coordination that is distorted away from the regular trigonal prismatic coordination encountered in the CoNCN aristotype due to vacancy and cation order. Finally, SQUID magnetometry unearths predominantly antiferromagnetic interactions with a transition to what appears to be a ferrimagnetically ordered state below 160 K.

Graphitic carbon nitrides on flexible carbon cloths, functionalized with ultra-dispersed zinc oxide and zinc ferrite, are proposed as green and economically viable electrocatalysts for photo-assisted ethanol oxidation.

Two-dimensional (2D) magnetic materials with exotic magnetic properties have garnered significant interest due to their potential applications in spintronics and data storage technologies. However, the limited availability of intrinsic 2D magnetic materials has driven efforts to induce and manipulate magnetism in otherwise nonmagnetic 2D systems through approaches such as chemical intercalation, defect engineering, and substitutional doping. Herein, we present a facile, chimie douce method for incorporating 3d transition metals (Cr, Co, and Ni) into the nonmagnetic PtSe2 sublattice. This synthetic approach enables control over layer thickness of Pt1-xMxSe2 (M = Cr, Co, Ni) nanosheets by varying the M identity and annealing conditions. Comprehensive scattering and spectroscopic characterizations confirm the successful and homogeneous substitution of M atoms at the Pt site, rather than intercalation, and reveal a strong correlation between nanosheet thickness and the identity of the substituting metal. High-temperature annealing of the nanosheets promotes an irreversible transformation toward the bulk phase, allowing for detailed characterization of structural and magnetic properties. A case study of Pt0.8Cr0.2Se2 reveals that nanosheet thickness plays a critical role in modulating local magnetic interactions. While Cr atoms in the as-synthesized few-layers-thick nanosheets exhibit predominantly short-range antiferromagnetic interactions, the emergence of short-range ferromagnetic exchange is revealed in the bulk material. Detailed ac susceptibility and remanent magnetization measurements further demonstrate that bulk Pt0.8Cr0.2Se2 adopts a frustrated magnetic ground state with clear signatures of ferromagnetic cluster-glass behavior. The systematic investigation presented herein establishes a clear and robust protocol for the synthesis and in-depth characterization of 2D transition-metal-substituted PtSe2 materials with varying layer thickness and paves a path toward their realization in spintronic and magnetic device applications.

Vinylene-linked covalent organic frameworks (COFs) are typically prepared via the Knoevenagel reaction under acid- or base-catalyzed solvothermal or benzoic anhydride-catalyzed solid-state conditions under reaction times spanning from 3 to 5 days. Herein, we show that the incorporation of a dipole moment into the COF building block accelerates the formation of ordered material. Under solvent-free Knoevenagel conditions, 3,8-dimethyl-4,7-phenanthroline (Phen) in combination with C3-symmetric aldehydes gives access to ordered hexagonal vinylene-linked COFs. A detailed study using triformylbenzene as counterpart evidences the formation of crystalline framework within hours. Theoretical and experimental studies indicate that the fast formation stems from favorable intermolecular interactions of the π-extended Phen building block due to the presence of a dipole moment, which also endows the material with excellent mechanical stability under ball milling. In addition, all prepared materials exhibited broad visible light absorption and narrow band gap energies of ≤2.48 eV and revealed photocatalytic activity for the degradation of dyes.

Pure and intergrown CHA/PHI nanocrystalline zeolites are synthesised using multiple inorganic cations as structure directing agents only, whereby the amount of each zeolite phase can be tuned. Their CO2 and N2 adsorption properties are explored.

Metal-organic frameworks (MOFs) offer a powerful platform for the rational design of photocatalysts, where systematic structural tuning can be employed for efficient solar-to-chemical energy conversion. Here, we establish a direct structure-activity relationship in a series of copper-metalated mixed-linker UiO-66 derivatives, UiO-66(COOH)x-Cu (0 ≤ x ≤ 2), incorporating increasing densities of free carboxylate groups in their MOF backbone. These functionalities determine both Cu coordination and in situ restructuring under the photocatalytic dehydrogenation of formic acid (FAc). Operando Fourier-transform infrared (FTIR) and X-ray absorption spectroscopy (XAS) reveal that the -COOH content dictates the evolution of the surface of the framework and Cu speciation during photocatalysis. FTIR demonstrates that intraframework anhydride formation correlates linearly with photocatalytic efficiency, while XAS evidences a light-induced restructuring of coordinated Cu(II)/Cu(I) species into a catalytically active Cu(I)/Cu(0) binary system in the presence of FAc. Time-resolved spectroscopy further indicates a photoinduced charge transfer from the Zr-oxo clusters to the Cu centers, enhancing the overall reactivity. Density functional theory (DFT) calculations corroborate these findings, showing that the number and spatial arrangement of carboxylates influence the Cu coordination stability and its restructuring dynamics. These insights reveal how linker functionalization governs metal speciation and dynamics in MOFs, offering design principles for next-generation light-driven catalytic systems.

Germanium is known to occupy tetrahedral sites by substituting silicon in germanosilicate zeolites. In this study, we present pioneering findings regarding the synthesis of zeolites with an MFI structure (GeMFI) incorporating a high germanium amount (16% Ge). Remarkably, the germanium atoms feature a slight electron deficiency with respect to GeO2, and the typical coordination number of 4, as usually reported for the germanosilicate zeolites, is exceeded, giving rise to Ge dimers in a double-bridge configuration. Notably, the compensation of the ammonium template is achieved not through fluorine ions in the [415262] cages of the framework, as conventionally considered, but rather through oxygen. The GeMFI zeolite with the high Ge content reported in this work demonstrated exceptional thermal and hydrothermal stability, surpassing up to 1050 °C, thanks to both the double-bridge configuration and the defect-free structure. The unexpected role of germanium in MFI zeolite challenges previous assumptions, representing a paradigm shift in the understanding of porous germanosilicate structures, paving the way for a reevaluation of their synthesis, hydrolysis, and potential applications.

Conventional molecular photocatalysts, such as bipyridine-based complexes, offer high adaptability and selectivity for the CO2 reduction reaction (CRR). However, due to their homogeneous phase operation, they face challenges such as rapid charge recombination, low performance, and recycling difficulties. Herein, we introduce an approach for knitting poly-single-atom photocatalysts (SAPCs) on metal-organic frameworks' (MOFs) external surface via on-surface photopolymerization of bipyridine (bpy)-based ligands onto a UiO-66 framework. By using [2,2'-bipyridine]-4,4'-diyl diacrylate monomer (A2bpy), our approach efficiently produces poly-bipyridine ligands (poly-[bpy]) as a brush shell around the MOF nanocrystal's core. The poly-bipyridine brush is then postmetalated with Re(CO)3Cl, to obtain a hybrid photocatalyst. The advanced structural analyses demonstrate high yields of both ligand photopolymerization and postfunctionalization (>45%) processes. Interestingly, the pores' accessibility of the UiO-66 core is well preserved, facilitating reactants' (e.g., H2O/CO2/HCO3-) absorption and release. The hybrid heterogeneous photocatalysts displayed 8 times higher activity for the photocatalytic CRR under simulated sunlight, with respect to the homogeneous catalyst (Re(bpy)(CO)3Cl), used as a benchmark and tested under the same experimental conditions. The better performance is attributed to several factors such as the UiO-66 pore affinity toward CO2/carbonate adsorption, the active site's accessibility, and the enhanced charge separation within the hybrid system.

Cu2SnS3 is the parent compound of a series of phases in the Cu2+xSn1-xS3 section (0 <= x <= 0.15) of the ternary Cu-Sn-S phase diagram, the crystal structure of which can be controlled by varying the synthesis process and/or through a fine-tuning of the chemical composition. Despite being structurally close to the sphalerite structure, the thermal transport of these compounds is strongly dependent on the exact lattice symmetry and degree of atomic disorder. Here, we investigate the lattice dynamics of the monoclinic ordered Cu5Sn2S7 (space group C2) and cubic disordered Cu5Sn2S6.65Cl0.35 (space group F43m) compounds by temperature-dependent powder inelastic neutron scattering (INS). In both cases, the INS spectra feature low-energy optical modes mostly weighed by the thermal motion of Cu atoms. The response of the INS spectra of Cu5Sn2S6.65Cl0.35 to temperature variations is indicative of quasi-harmonic behavior. Combined with analyses of the low-temperature specific heat, these findings show that the significant lowering of the lattice thermal conductivity in cubic Cu5Sn2S6.65Cl0.35 is due to a reduced phonon mean free path tied to the increased level of disorder in the unit cell. These results highlight how the stabilization of highly symmetric, yet strongly disordered crystal structures akin to those observed in high-entropy alloys, can lead to a drastic reduction in the heat transport, offering an effective approach to design high-performance thermoelectric sulfides.

The low-temperature modification of beta-Ag2Se has proven to be useful as a near-room-temperature thermoelectric material. Over the past years, research has been devoted to interstitial, vacancy, and substitutional doping into the parent beta-Ag2Se structure, aiming at tuning the material's charge and heat transport properties to enhance thermoelectric performance. The transformation of beta-Ag2Se into alpha-Ag2Se at similar to 134 degrees C and the low solubility of dopants are the main obstacles for the doping approach. Herein, we report a facile, safe, scalable, and cost-effective benchtop approach to successfully produce metal-doped beta-Ag2Se. The doped materials display a remarkable enhancement of thermoelectric performance with a record-high peak zT of 1.30 at 120 degrees C and an average zT of similar to 1.15 in the 25-120 degrees C range for 0.2 at. % Zn-doped Ag2Se. The enhancement in zT is attributed to point defects created by Zn doping into Ag vacancies/interstitials, which enhances the scattering of phonons and tunes the charge carrier properties, leading to the significant suppression of thermal conductivity. The simplicity of the synthetic method developed herein and the high performance of the final products provide an avenue to produce high-quality Ag2Se-based thermoelectric materials.

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Correction for 'Plasma-assisted fabrication of ultra-dispersed copper oxides in and on C-rich carbon nitride as functional composites for the oxygen evolution reaction' by Mattia Benedet et al., Dalton Trans., 2024, https://doi.org/10.1039/d4dt02186j.

Atmospheric pollution has been recognized as a primary global emergency, especially in large cities and industrial areas. Among the most common harmful pollutants, nitrogen oxides (NOx) are responsible for a plethora of adverse effects, and their effective elimination from air has become an imperative task. In this regard, photocatalysis stands as an attractive technology for NOx degradation, provided that low-cost and efficient visible -light photocatalysts are developed. In this regard, the construction of heterojunctions between energy band-matched semiconductors is an effective strategy to boost the ultimate material photoactivity. In the present study, green heterocomposites based on MgAlTi layered double hydroxides (LDHs) and graphitic carbon nitride (gCN) are prepared using an amenable and cost-effective route. A proper modulation of the system characteristics, as demonstrated by a comprehensive investigation, enabled to obtain very attractive DeNO(x) performances thanks to the efficient construction of MgAlTi/gCN heterojunctions with tailored features. The formation of the target heterocomposites significantly enhances the visible light photoactivity of the pristine LDH, boosting nitrogen monoxide transformation to nitrites/nitrates with a remarkable recycling stability. Overall, the presently reported results open the door to a profitable system exploitation for air purification under real-world conditions, with considerable impact on both human wellbeing and environmental protection.