Defects tune the acidic strength of amorphous aluminosilicates.

Crystalline zeolites have high acidity but limited utility due to microporosity, whereas mesoporous amorphous aluminosilicates offer better porosity but lack sufficient acidity. In this work, we investigated defect engineering to fine-tune the acidity of amorphous acidic aluminosilicates (AAS). Here we introduced oxygen vacancies in AAS to synthesize defective acidic aluminosilicates (D-AAS).

Designed Nanoarchitectures of a BiOBr/BiOI Nanosheet Heterojunction Anchored on Dendritic Fibrous Nanosilica as Visible-Light Responsive Photocatalysts.

Heterojunctions, particularly those involving BiOBr/BiOI, have attracted significant attention in the field of photocatalysis due to their remarkable properties. In this study, a unique architecture of BiOBr/BiOI was designed to facilitate the rapid transfer of electrons and holes, effectively mitigating the recombination of electron-hole pairs. Accordingly, the BiOBr/BiOI nanosheet heterojunction was anchored on dendritic fibrous nanosilica (DFNS) by the immobilization of BiO nanodots in DFNS and the subsequent reaction with HBr and then HI vapors at room temperature.

Probing the Surface of Oxide Nanoparticles Using DNP-Enhanced High-Resolution NMR of Quadrupolar Nuclei.

The surfaces of nanomaterials with applications in optoelectronics and catalysis control their physicochemical properties. NMR spectroscopy, enhanced by dynamic nuclear polarization (DNP), is a powerful approach to probe the local environment of spin-1/2 nuclei near surfaces. However, this technique often lacks robustness and resolution for half-integer quadrupolar nuclei, which represent more than 66% of the NMR-active isotopes.

Pt-doped Ru nanoparticles loaded on 'black gold' plasmonic nanoreactors as air stable reduction catalysts.

This study introduces a plasmonic reduction catalyst, stable only in the presence of air, achieved by integrating Pt-doped Ru nanoparticles on black gold. This innovative black gold/RuPt catalyst showcases good efficiency in acetylene semi-hydrogenation, attaining over 90% selectivity with an ethene production rate of 320 mmol g h. Its stability, evident in 100 h of operation with continuous air flow, is attributed to the synergy of co-existing metal oxide and metal phases.

Acetylene Semi-Hydrogenation at Room Temperature over Pd-Zn Nanocatalyst.

A reaction of fundamental and commercial importance is acetylene semi-hydrogenation. Acetylene impurity in the ethylene feedstock used in the polyethylene industry poisons the Ziegler-Natta catalyst which adversely affects the polymer quality. Pd based catalysts are most often employed for converting acetylene into the main reactant, ethylene, however, it often involves a tradeoff between the conversion and the selectivity and generally requires high temperatures.

Design of porphyrin-based frameworks for efficient visible light-promoted reduction of CO from dilute gas: Combined experimental and theoretical investigation.

The photocatalytic carbon dioxide reduction (COR) coupled with hydrogen evolution reaction (HER) constitutes a promising step for a sustainable generation of syngas (CO + H), an essential feedstock for the preparation of several commodity chemicals. Herein, visible light/sunlight-promoted catalytic reduction of CO and protons to syngas using rationally designed porphyrin-based 2D porous organic frameworks, POF(Co/Zn) is demonstrated. Indeed, POF(Co) showed superior catalytic performance over the Zn counterpart with CO and H generation rates of 1104 and 3981 μmol gh, respectively.

Surface plasmon-enhanced photo-driven CO hydrogenation by hydroxy-terminated nickel nitride nanosheets.

The majority of visible light-active plasmonic catalysts are often limited to Au, Ag, Cu, Al, etc., which have considerations in terms of costs, accessibility, and instability. Here, we show hydroxy-terminated nickel nitride (NiN) nanosheets as an alternative to these metals.

Defects Tune the Strong Metal-Support Interactions in Copper Supported on Defected Titanium Dioxide Catalysts for CO Reduction.

A highly active and stable Cu-based catalyst for CO to CO conversion was demonstrated by creating a strong metal-support interaction (SMSI) between Cu active sites and the TiO-coated dendritic fibrous nano-silica (DFNS/TiO) support. The DFNS/TiO-Cu10 catalyst showed excellent catalytic performance with a CO productivity of 5350 mmol g h (i.e.

Insights into the CO Capture Characteristics within the Hierarchical Pores of Carbon Nanospheres Using Small-Angle Neutron Scattering.

Understanding adsorption processes at the molecular level has transformed the discovery of engineered materials for maximizing gas storage capacity and kinetics in adsorption-based carbon capture applications. In this work, we studied the molecular mechanism of gas (CO, H, methane, and ethane) adsorption inside an interconnected porous network of carbon. This was achieved by synthesizing novel macro-meso-microporous carbon (MC) nanospheres with interconnected pore structures.

Nickel-Laden Dendritic Plasmonic Colloidosomes of Black Gold: Forced Plasmon Mediated Photocatalytic CO Hydrogenation.

In this work, we have designed and synthesized nickel-laden dendritic plasmonic colloidosomes of Au (black gold-Ni). The photocatalytic CO hydrogenation activities of black gold-Ni increased dramatically to the extent that measurable photoactivity was only observed with the black gold-Ni catalyst, with a very high photocatalytic CO production rate (2464 ± 40 mmol g h) and 95% selectivity. Notably, the reaction was carried out in a flow reactor at low temperature and atmospheric pressure without external heating.

Construction of a 2D/2D g-CN/NiCr-LDH Heterostructure to Boost the Green Ammonia Production Rate under Visible Light Illumination.

Photocatalytic N fixation has emerged as one of the most useful ways to produce NH, a useful asset for chemical industries and a carbon-free energy source. Recently, significant progress has been made toward designing efficient photocatalysts to achieve this objective. Here, we introduce a highly active type-II heterojunction fabricated via integrating two-dimensional (2D) nanosheets of exfoliated g-CN with nickel-chromium layered double hydroxide (NiCr-LDH).

Polyethylenimine assisted non-monotonic jamming of colloids during evaporation induced assembly and its implication on CO sorption characteristics.

We report a detailed study of hierarchically organized silica-polyethylenimine (PEI) microspheres achieved through evaporation-induced assembly. Due to complex interactions between oppositely-charged silica nanoparticles and PEI, non-monotonic jamming of the colloidal particles is manifested. With an increase in the polymer concentration, the local volume fraction of the silica particles decreases from 0.

Dendritic Fibrous Nanosilica: Discovery, Synthesis, Formation Mechanism, Catalysis, and CO Capture-Conversion.

ConspectusSilica-based mesoporous nanomaterials have been widely used for a range of applications. Although mesopore materials (such as MCM-41 and SBA-15) possess high surface area, due to their tubular pore structures, pore accessibility is restricted, which causes limitations in mass transport. A new nanosilica was needed to overcome these challenges, including better accessibility, controllable particle size, and good stability.

Direct CO capture and conversion to fuels on magnesium nanoparticles under ambient conditions simply using water.

Converting CO directly from the air to fuel under ambient conditions is a huge challenge. Thus, there is an urgent need for CO conversion protocols working at room temperature and atmospheric pressure, preferentially without any external energy input. Herein, we employ magnesium (nanoparticles and bulk), an inexpensive and the eighth-most abundant element, to convert CO to methane, methanol and formic acid, using water as the sole hydrogen source.

Visible Light-Driven Highly Selective CO Reduction to CH Using Potassium-Doped g-CN.

Establishment of an efficient and robust artificial photocatalytic system to convert solar energy into chemical fuels through CO conversion is a cherished goal in the fields of clean energy and environmental protection. In this work, we have explored an emergent low- nitrogen-rich carbon nitride material g-CN (analogue of g-CN) for CO conversion under visible light illumination. A significant enhancement of the CH production rate was detected for g-CN in comparison to that of g-CN.

Lithium silicate nanosheets with excellent capture capacity and kinetics with unprecedented stability for high-temperature CO capture.

An excessive amount of CO is the leading cause of climate change, and hence, its reduction in the Earth's atmosphere is critical to stop further degradation of the environment. Although a large body of work has been carried out for post-combustion low-temperature CO capture, there are very few high temperature pre-combustion CO capture processes. Lithium silicate (LiSiO), one of the best known high-temperature CO capture sorbents, has two main challenges, moderate capture kinetics and poor sorbent stability.

Defective TiO for photocatalytic CO conversion to fuels and chemicals.

Photocatalytic conversion of CO into fuels and valuable chemicals using solar energy is a promising technology to combat climate change and meet the growing energy demand. Extensive effort is going on for the development of a photocatalyst with desirable optical, surface and electronic properties. This review article discusses recent development in the field of photocatalytic CO conversion using defective TiO.

Gold cluster-loaded dendritic nanosilica: single particle luminescence and catalytic properties in the bulk.

We report a hybrid material in which surface anchoring-induced enhanced luminescence of AuQC@BSA clusters on high surface area dendritic fibrous nanosilica of 800 nm diameter enabled their luminescence imaging at a single particle level. The photophysical and structural properties of the hybrid material were characterized by various spectroscopic and microscopic techniques. Concomitant imaging using scattering and luminescence of such mesostructures and their response to analytes have been used to develop a chemical sensor.

Origin of the Hierarchical Structure of Dendritic Fibrous Nanosilica: A Small-Angle X-ray Scattering Perspective.

The discovery of dendritic fibrous nanosilica (DFNS) has attracted great attention to the field of catalysis, CO capture, drug delivery due to its distinct morphology, and pore size distribution. Despite extensive research, the understanding of the DFNS formation process and its internal structure remains incomplete as microscopy and gas sorption techniques were not able to provide necessary in-depth structural information due to their inherent limitations. In the current work, we present a structural model of DFNS derived using small-angle X-ray scattering (SAXS) supported by Xe nuclear magnetic resonance (NMR), which provided intricate details of DFNS and its internal structure.

Nitrogen doped carbon spheres with wrinkled cages for the selective oxidation of 5-hydroxymethylfurfural to 5-formyl-2-furancarboxylic acid.

Nitrogen doped carbon spheres with wrinkled cages (NCSWCs), which were used for the first time as metal-free catalysts, exhibited high catalytic activity and selectivity in the oxidation of 5-hydroxymethylfurfural (HMF) to 5-formyl-2-furancarboxylic acid (FFCA) under base-free conditions using tert-butyl hydroperoxide (TBHP) as the oxidant. The mechanistic studies found that this reaction was catalyzed by the synergy between NCSWCs and TBHP. The density functional theory (DFT) calculations further suggested that the hydroperoxyl radicals from TBHP adsorbed on the carbon atoms adjacent to the graphitic N atoms are the active sites.

Dendritic Fibrous Nanosilica (DFNS) for RNA Extraction from Cells.

Efficient RNA extraction is critical for all downstream molecular applications and techniques. Despite the availability of several commercial kits, there is an enormous scope to develop novel materials that have high binding and elution capacities. Here, we show that RNA from the cells can be extracted by dendritic fibrous nanosilica (DFNS) with higher efficiency than commercially available silicas.

Catalytic nanosponges of acidic aluminosilicates for plastic degradation and CO to fuel conversion.

The synthesis of solid acids with strong zeolite-like acidity and textural properties like amorphous aluminosilicates (ASAs) is still a challenge. In this work, we report the synthesis of amorphous "acidic aluminosilicates (AAS)", which possesses Brønsted acidic sites like in zeolites and textural properties like ASAs. AAS catalyzes different reactions (styrene oxide ring-opening, vesidryl synthesis, Friedel-Crafts alkylation, jasminaldehyde synthesis, m-xylene isomerization, and cumene cracking) with better performance than state-of-the-art zeolites and amorphous aluminosilicates.

Defects in nanosilica catalytically convert CO to methane without any metal and ligand.

Active and stable metal-free heterogeneous catalysts for CO fixation are required to reduce the current high level of carbon dioxide in the atmosphere, which is driving climate change. In this work, we show that defects in nanosilica (E' centers, oxygen vacancies, and nonbridging oxygen hole centers) convert CO to methane with excellent productivity and selectivity. Neither metal nor complex organic ligands were required, and the defect alone acted as catalytic sites for carbon dioxide activation and hydrogen dissociation and their cooperative action converted CO to methane.