7 research outputs found
Band gap engineering of amine functionalized Ag(I)-based coordination polymers and their plasmonic Ag0 coupled novel visible light driven photo-redox system for selective oxidation of benzyl alcohol
We developed a one-pot synthetic route to design Ag nanoparticles (NPs) coupled mixed ligand Ag(I) coordination polymer (CP), Ag@Ag(I)-CP (40% NH2) for photocatalysis. Initial combined (experimental and DFT) study on mixed ligand CPs demonstrates that a rational substitution of ligand L1: 1,4-benzenedicarboxylate by L2: 2 amino 1,4-benzenedicarboxylate enhances porosity and reduction of energy gap (2.9 eV) due to highest occupied crystal orbital (HOCO; + 2.4 V vs. NHE) suitable for BA oxidation selectively to benzaldehyde (BD) ((E0 BA/BD = + 1.9 V). When Ag NP (~ 6–7 nm) is in-situ encapsulated on CP, formed a coupled structure Ag@Ag(I)-CP (40% NH 2), which offered advantages on BA oxidation (k (O2) = 7.4 × 10-4 min-1; yield: 19.1% BD, and k (persulfate) = 38.7 × 10-4 min-1; yield: 54.1% BD) along with significant stability, reusability and competitiveness than other Ag or precious metal NPs. The new material offers numerous possibilities for applications in oxidative organic transformations reactions. The simple synthetic strategy demonstrated in this work for the coupling of Ag(I) based coordination polymers with metal nanoparticles at the molecular scale for semiconductor like applications under visible light will accelerate extensive research in near future
Photoactive Ag(I)-based coordination polymer as a potential semiconductor for photocatalytic water splitting and environmental remediation: experimental and theoretical approach
Metal–organic frameworks or metal coordination polymers (CPs) with controlled structure on the micro/nanoscale have attracted intense interest for potential applications in a wide variety of fields, such as energy storage and conversion, chemical and biological sensing, and catalysis. Here, we report a new class of photocatalytic material, Ag(I)-based nano-micro-structured coordination polymer (Ag(I)-CP), which offers performance at a level competitive with known semiconductors in photocatalytic water oxidation and oxidation of organic compounds, such as dye/organic pollutants present in contaminated water. The coordination polymer was synthesized by a wet-chemical route and has been characterized using powder X-ray diffraction, X-ray photoelectron spectroscopy, and electron microscopy. The Ag(I)-CP has notable semiconducting characteristics and charge transfer ability due to ligand-centered charge transfer in combination with metal-to-ligand charge transfer (Ag–O cluster to ligand center), as established from experimental absorption, luminescence, and photoelectrochemical measurements alongside density functional theory calculations. Notably, Ag(I)-CP exhibits a highly reactive valance band potential +3.40 V vs NHE, composed of hybridized state of O 2p and C 2p through the organic linker and Ag 4d; this acts as an active center for the generation of reactive oxygen species, i.e., hydroxyl radical and h+ under photocatalytic conditions. Consequently, the photogenerated species facilitate effective oxidations of water and organic contaminants such as tartrazine, rhodamine B, and 2,4-dichlorophenol under UV light irradiation. Furthermore, our results suggest that the Ag(I)-CP could be used as a promising material for the development of heterostructure for a variety of photoassisted redox catalysis reactions
Strategic Synthesis of SiO2‑Modified Porous Co3O4 Nano-Octahedra Through the Nanocoordination Polymer Route for Enhanced and Selective Sensing of H2 Gas over NOx
Sustainable Design of Hierarchically Porous Ag<sub>3</sub>PO<sub>4</sub> Microspheres through a Novel Natural Template and Their Superior Photooxidative Capacity
Uniform hierarchical
Ag<sub>3</sub>PO<sub>4</sub> porous microspheres
were synthesized for the first time by a sustainable route based on
a novel natural bone glue (BG)-assisted one-step precipitation reaction
at room temperature. By varying experimental conditions such as the
bone glue content, template constituents (amino acid, alginic acid),
precursor concentration, temperature, pH, and reaction time, we could
tune the morphology, porosity, size, and properties of Ag<sub>3</sub>PO<sub>4</sub>. All of the phases, microstructures with different
architectures, and textural properties of the Ag<sub>3</sub>PO<sub>4</sub> were characterized by Fourier transform infrared spectroscopy,
X-ray diffraction, scanning electron microscopy, transmission electron
microscopy, Brunauer–Emmett–Teller surface area analysis,
and UV–vis diffuse reflectance spectroscopy. The oxidation
state, local structure, and purity of the prepared Ag<sub>3</sub>PO<sub>4</sub> were further characterized by X-ray photoelectron spectroscopy,
Raman spectroscopy, and thermogravimetric analysis. The influence
of the template on the morphology was characterized by syntheses of
Ag<sub>3</sub>PO<sub>4</sub> using different templates such as glycine,
alanine, and alginic acid, and products such as pyramidal-shaped Ag<sub>3</sub>PO<sub>4</sub>, Ag<sub>3</sub>PO<sub>4</sub> dodecahedra,
and coiled-rod-like porous Ag<sub>3</sub>PO<sub>4</sub> were obtained,
respectively. This revealed that self-assembly of the collagen protein
present in the bone glue plays a significant role as a structure-directing
agent, crystal growth modifier, and aggregation-orienting agent in
the formation of unique Ag<sub>3</sub>PO<sub>4</sub> porous microspheres.
Detailed photocatalytic studies on aqueous rhodamine B and 2,4-dichlorophenol
(2,4-DCP) in the presence of Ag<sub>3</sub>PO<sub>4</sub> porous microspheres
exhibited enhanced photocatalytic degradation under visible light
that was significantly higher than for other architectures. The findings
of this study should offer new insights into the development of porous
hierarchical materials as high-performance visible-light photocatalysts
and their potential utilization in environmental sustainability
Strategic Synthesis of SiO<sub>2</sub>‑Modified Porous Co<sub>3</sub>O<sub>4</sub> Nano-Octahedra Through the Nanocoordination Polymer Route for Enhanced and Selective Sensing of H<sub>2</sub> Gas over NO<sub><i>x</i></sub>
In this work, a strategic synthesis
of Co<sub>3</sub>O<sub>4</sub> nano-octahedra was developed through
the facile nanoscale coordination
polymer (NCP) route, which was further modified by SiO<sub>2</sub> to be used as a sensor for enhanced sensing of hydrogen. The CoÂ(II)-NCP-derived
Co<sub>3</sub>O<sub>4</sub> octahedra and SiO<sub>2</sub>-modified
Co<sub>3</sub>O<sub>4</sub> octahedra were characterized using Fourier
transform infrared, powder X-ray diffraction, Brunauer–Emmett–Teller,
thermogravimetric analysis, field emission scanning electron microscopy,
high-resolution transmission electron microscopy, X-ray photoelectron
spectroscopy, and hydrogen temperature-programmed reduction (H<sub>2</sub>TPR) techniques. The SiO<sub>2</sub>-modified Co<sub>3</sub>O<sub>4</sub> sensor exhibited a stronger and selective electrical
response to H<sub>2</sub> gas over NO<sub><i>x</i></sub> at 225 °C than CoÂ(II)-NCP-derived Co<sub>3</sub>O<sub>4</sub> octahedra and the conventional Co<sub>3</sub>O<sub>4</sub> powder.
The composite sensor shows faster recovery and significant repeatability
than the other two. The enhancement in the sensing performance of
the SiO<sub>2</sub>-modified Co<sub>3</sub>O<sub>4</sub> octahedron
was explained by the effectiveness of surface modification, controlled
morphology, and combination of synergistic effect of Co<sub>3</sub>O<sub>4</sub> and SiO<sub>2</sub>. Surface engineering of the as-prepared
Co<sub>3</sub>O<sub>4</sub> nano-octahedra with an exposed (111) surface
plane and later SiO<sub>2</sub> modification facilitates effective
gas adsorption, resulting in enhancement in sensing and selectivity
over NO<sub><i>x</i></sub>. The details of the synergistic
effect and the plausible reasons for the improvement in gas-sensing
parameters are discussed here. This study would offer new directions
for development on the controlled synthesis of porous materials, in
general, and in gas sorption or sensing, in particular