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A pectin-based one-pot aqueous approach was reported to valorize coco coir into multifunctional biocomposites. These biocomposites were demonstrated to be effective hydroponic growth media.

CeO2-Catalyzed esterification of CO2, a well-known greenhouse gas, with methanol has been widely recognized as a promising alternative method to produce dimethyl carbonate (DMC). Herein, we performed a comprehensive study of catalytic mechanisms underlying the formation of DMC from CO2 and methanol on both stoichiometric and reduced CeO2(111) and (110) surfaces. To this end, the saddle-point searching algorithm is employed. Specifically, using the monomethyl carbonate (MMC) as the key intermediate, a three-step Langmuir-Hinshelwood (LH) mechanism, including the formation and esterification of monomethyl carbonate and removal of water molecule, is identified for the catalytic DMC formation on either the reduced or the stoichiometric CeO2(111) and (110) surfaces. For both CeO2(111) and (110) surfaces, our study indicates that the presence of oxygen vacancies can markedly lower the activation energy barrier. Different rate-limiting steps are identified, however, for the reduced CeO2(111) and (110) surfaces. Successful identification of the rate-limiting step and the associated active CO2 species will provide atomic-level guidance on selection of metal-oxide-based catalysts toward direct synthesis of DMC from the green-house gas CO2 and methanol.

Recent increasing uses of ceria in research and industrial applications have fostered continuing developments of efficient routes to synthesize the material. Here we report our investigation of the effects and the mechanistic roles of lithium acetate to accelerate the growth of crystalline ceria nanoparticles in ozone-mediated synthesis. By increasing the mole ratio of the acetate to cerium nitrate in the reactions, the reaction yields of ceria nanoparticles were observed to increase from ca. 10% to up to over 90% by cerium content in 30 min reactions. Microscopy images and Raman spectra of the as-synthesized nanoparticles revealed that increasing the acetate additions led to a decrease in average particle size and size range but an increase in crystallinity. Through analyzing the organic by-products in the reaction mixtures, the acetate was inferred to base-catalyze the formation of acetals and cerium complexes and accelerate the formation of Ce–O–Ce bonds and hence the growth of ceria nanoparticles through alcohol-like condensation reactions.

Reactive oxygen species (ROS) are powerful oxidants generated in both biological systems and natural environments. Though enzyme-mimic activity and Fenton-like reactions have been postulated to explain how ceria nanoparticles and ROS are involved in the catalytic decomposition of hydrogen peroxide (H2O2), the corresponding reaction kinetics for this reaction have not yet been completely resolved. Here we present our investigation of the structure–activity relationship of ceria nanostructures for the generation of hydroxyl radicals through the catalytic decomposition of H2O2. Different nanostructured ceria including nanorods (NR), nanocubes (NC), and nanooctahedra (NO), together with commercial ceria, were examined to elucidate the relationship between the morphology and reaction kinetics. The initial relative production rates of hydroxyl radicals over different ceria nanostructures were determined using fluorescence measurements and were applied to obtain the apparent activation energy for their intrinsic activity comparisons. The activity trend of the order: ceria NR > ceria NC > ceria NO > commercial ceria was observed. This trend was rationalized and assessed using activity descriptive factors including the intensity ratio of Raman bands of vibration modes due to atomic defects, the percentage of surface Ce3+ content, and the average coordination number of oxygen anions surrounding each cerium cation in the ceria samples.

Pulsed dipolar spectroscopy (PDS) is a powerful tool to explore conformational changes of membrane proteins (MPs). However, the MPs suffer from relatively weak dipolar signals due to their complex nature in membrane environments, which consequently reduces the interspin distance resolution obtainable by PDS. Here we report the use of nanodiscs (NDs) to improve the distance resolution. Two genetically engineered membrane scaffold protein mutants are introduced, each of which is shown to form double-labeled ND efficiently and with high homogeneity. The resultant interspin distance distribution is featured by a small distribution width, suggesting high resolution. When PDS is performed on a binary mixture of the double-labeled ND devoid of MPs and the un-labeled ND with incorporated double-labeled MPs, the overall amplitude of dipolar signals is increased, leading to a critical enhancement of the distance resolution. A theoretical foundation is provided to validate the analysis. With this approach, the determination of MP structures can be studied at high resolution in NDs.

We report the growth of carbon dioxide (CO2) whiskers at low temperatures (−70 °C to −65 °C) and moderate pressure (4.4 to 1.0 bar). Their axial growth was assessed by optical video analysis. The identities of these whiskers were confirmed as CO2 solids by Raman spectroscopy. A vapor–solid growth mechanism was proposed based on the influence of the relative humidity on the growth.

Three novel anthracene-based organic dyes, denoted as AN-11, AN-12 and AN-14, were synthesized for outdoor and indoor dye-sensitized solar cell studies. Laboratory-fabricated small cells, as well as rigid and flexible modules, were prepared and analyzed for their photovoltaic performance under simulated outdoor and indoor conditions. Owing to the panchromatic absorption of visible light, the AN-11 module gives rise to a very black color and superior photovoltaic performance. Significantly, the AN-11 rigid module with a large active area of 26.80 cm2 outperforms its Z907 counterpart under indoor conditions, reaching an overall efficiency of 11.94% under 1000 lux of T5 fluorescent light. In addition, the AN-11 module exhibits good stability during weather stress tests. Finally, the AN-11 dye is cost-effective and our studies show that the photovoltaic performance of the solar cells is not affected upon lowering the synthetic cost and increasing the synthetic scale.

Germanium oxide (GeO2) nanoparticles were synthesized with a nearly 100% production yield in a nonionic reverse micelle system at ambient temperature. The procedure is a facile and energy saving strategy for producing germanium oxide nanoparticles with ultra large throughput. As-prepared GeO2 nanoparticles can be directly used as anode materials without any post-treatment or other supplementary additives for lithium ion batteries. GeO2-anodes exhibited good electrochemical performance in terms of both gravimetric and volumetric capacity. The GeO2 anodes have a reversible capacity of approximately 1050 mA h g−1 at a rate of 0.1C, close to its theoretical capacity (1100 mA h g−1), and good rate capability without severe capacity decade. The volumetric capacity of the GeO2 anodes reaches 660 mA h cm−3, which is higher than the performance of commercial graphite anode (370–500 mA h cm−3). Coin type and pouch type full cells assembled for electronic devices applications were also demonstrated. A single battery is shown to power LED array over 120 bulbs with a driving current of 650 mA. Based on the above, the micelle process of GeO2 nanoparticle synthesis provides a possible solution to high-capacity nanoparticles' scalable manufacturing for lithium ion battery applications.

A new class of porphyrin-containing polyimides, ZnPor-s-DSDA, ZnPor-t-DSDA, Por-s-DSDA and Por-t-DSDA, were synthesized from porphyrin-containing diamines and 3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride for resistor-type memory applications. The effect of the linkage and zinc metal was investigated by electrochemistry, molecular simulations, and memory behaviors. The memory devices with different retention times derived from polymers ZnPor-s-DSDA (WORM, >3 h) and ZnPor-t-DSDA (DRAM, 30 s) demonstrated the importance of the linkage effect, and the insulation property of polyimides Por-s-DSDA and Por-t-DSDA also implies a crucial memory behavior by metal chelation.

A quasi in situ X-ray absorption study demonstrated that the disproportionation of hydrogen peroxide (H2O2) promoted by ceria nanorods was associated with a reversible Ce(3+)/Ce(4+) reaction and structural transformations in ceria. The direction of this reversible reaction was postulated to depend on the H2O2 concentration and the fraction of Ce(3+) species in ceria nanorods.

Three porphyrin dyes with different electron-donating groups were prepared to compare their photovoltaic performance in dye-sensitized solar cells. LWP12 is based on LD31 which has a complicated, piece-together electron-donating group, whereas LWP13 and LWP14 have merged substituents with electron-donating and absorption-broadening abilities. The results in this work suggest that consolidated anthryl donors may be used to design highly efficient photosensitizers.

We design a novel solution-processable polyimide ZnPor-t-DSDA with porphyrin moiety (electron donor) and sulfone-containing phthalimide (electron acceptor) for polymer memory applications. The resulting memory device can be switched from low-conductivity (OFF) to high-conductivity (ON) by both positive and negative sweeps, exhibiting symmetry biswitching characteristic with a short retention time (30 s). On the basis of the simulation calculation, the coplanar structure between donor and acceptor units results in charge transferring easily back to its original state after being excited by an electric field.

A hybrid catalyst composed of phosphotungstic acid coated cerium oxide nanoparticles was demonstrated to catalyze the one-pot conversion of cellobiose, the disaccharide unit of cellulose, to a monosaccharide mixture of glucose and mannose. A high % conversion of cellobiose (up to 99%) was achieved resulting in a yield of mannose up to 15.8%. The yield of mannose from a glucose starting material was 22.8%, exceeding those of previous cerium-based glucose epimerization catalysts. The components of the hybrid material were revealed to function synergistically via a two-step process. Cellobiose was hypothesized to be first hydrolyzed to glucose, which was subsequently epimerized to mannose by the cerium ions leached from the catalyst. The 13C NMR spectroscopic study suggested that the epimerization likely occurred by way of a 1,2-carbon shift reaction mechanism.

In this study we probe the electrocatalytic activity of Pt nanoparticles supported on ceria nanoparticles (NPs) and nanorods (NRs) in the ethanol oxidation reaction (EOR) in alkaline media. The goal of this study was to relate morphology, support structure and composition to the EOR catalytic activity by using in situ X-ray absorption fine structure (XAFS) studies. Cyclic voltammetry experiments showed that both ceria supported catalysts (NP vs. NR) had similar peak current densities at fast scan rates, however at slow scan rates, the ceria NR catalyst showed superior catalytic activity. In situ XAFS studies in KOH showed that both ceria supported catalysts had more electron density in their d-band (with the ceria NR having more electron density overall) than ceria - free Pt/Vulcan standard. However, in an ethanol solution the ceria NR catalyst had the least electron density. We propose that this change is due to the increased charge transfer efficiency between the ceria nanorod support and platinum. In the KOH solution, the increased electron density makes the platinum less electrophilic and hinders Pt-OH bond formation. In the EtOH solution, platinum's increased nucleophilicity facilitates the bond formation between Pt and the electron deficient carbon in ethanol which in turn withdraws the electron density from platinum and increases the white line intensity as observed in the XAS measurements.

We designed a dimeric porphyrin dye (LDD1) based on an efficient push–pull zinc porphyrin (LD14) with extended π-conjugation through coupling of two zinc porphine cores via an acetylene bridge at the meso position of the porphyrin to extend the absorption spectrum effectively into the near infrared region. The effect of dye aggregation among porphyrin molecules was significantly suppressed when the LDD1 and LD14 dyes were co-sensitized on a nanocrystalline TiO2 film in a dye-sensitized photovoltaic system. The light-harvesting ability of the device exhibits a panchromatic feature covering a broad spectral region from 400 nm to 900 nm, which results in a short-circuit current density of 21.3 mA cm−2 and a power conversion efficiency of 10.4% in an iodine-based solar cell.

A series of new porphyrins (LWP1–4) for dye-sensitized solar cells (DSSCs) were prepared by attaching pyrene or a 4-dimethylaminophenyl group in combination with anthracene to modify the porphyrin core. Fundamental studies showed that incorporation of these moieties renders feasible tuning of spectral and redox properties of the porphyrins. Significantly, DSSCs adopting the LWP1 dye exhibit energy conversion up to 800 nm without compromising the overall efficiency. This achievement is attributed to the collective effects of the broadened and red-shifted IPCE spectra, elevated energy levels at the excited states of the dyes, suitable dye soaking processes, and suitable electron-donating substituents.

The catalytic activity of platinum (Pt) nanoparticles (NPs) towards methanol electrooxidation in alkaline media was demonstrated to be dependent on their interactions with their nanostructured ceria support. Ceria nanorods (NRs) with diameters of 5 to 10 nm and lengths of 15 to 50 nm as well as ceria NPs with diameters of 2 to 6 nm were applied as supports for similarly sized Pt NPs with diameters of 2 to 5 nm. Cyclic voltammetry data showed that Pt NPs supported on ceria NPs exhibited a 2-to-5-fold higher catalytic current density versus ceria NRs. X-ray photoelectron spectroscopic data indicated that Pt NPs deposited onto ceria NRs were disproportionally composed of oxidized species (Pt2+, Pt4+ and Pt–O–M) rather than Pt0 while Pt NPs on ceria NPs mainly consisted of Pt0. Stronger metal-support interactions between Pt NPs and ceria NRs are postulated to induce preferential oxidation of Pt NPs and consequently decrease the catalytic sites and overall activity.

Multi-functional anode catalysts composed of platinum (Pt) nanoparticles electrodeposited on 2 wt% Pt decorated ceria (Pt:CeO2−x) nanorod supports were shown to enhance the alkaline electrocatalytic oxidation of methanol, ethanol and n-butanol over electrodeposited Pt nanoparticles alone or ones supported with pure ceria nanorods. The Pt:CeO2−x nanorod support was demonstrated to increase the current density of the investigated alkaline electrooxidation of methanol, ethanol and n-butanol by more than 30% over the other two catalysts.

A new porphyrin sensitizer, LD31, was designed based on a donor–π–acceptor structure, in which an ethynyl-anthracenyl moiety was inserted between the dioctylaminophenyl group and the porphyrin core in order to extend the π-conjugation of the dye for improved light-harvesting ability. The device made of LD31 exhibited panchromatic spectral features covering the whole visible region and further extending over 800 nm. When combined with an organic dye (AN-4), the performance of the LD31/AN-4 co-sensitized device attained JSC/mA cm−2 = 20.3, VOC/mV = 704, FF = 0.72, and the overall efficiency of power conversion η = 10.3%.

This study is a thorough evaluation of clay-based Layer-by-Layer (LbL) coatings intended to reduce the flammability of polymeric materials. Through a systematic variation of a baseline coating recipe, an ideal combination of the coating attributes that provides a rapidly developing coating with an optimum balance of flammability, mechanical, and physical attributes on a complex 3D porous substrate, polyurethane foam (PUF) was identified. Using a unique trilayer (TL) assembly approach, the coating growth was significantly accelerated by the polymer (poly(acrylic acid) (PAA)/branched polyethylenimine (BPEI)) concentration in the formulation. However, to significantly reduce flammability without compromising other performance attributes, the concentration of the nanoparticle fire retardant (nanoFR, clay) suspension was critical. This study has resulted in the most significant reduction in PUF flammability using LbL technology without compromising any of the mechanical or physical attributes of the PUF. More specifically, a reduction in the peak heat release rate (pHRR) and average heat release rate (aHRR) of 33% and 78%, respectively, has been achieved. This reduction in flammability is at least two times more effective than commercial fire retardants and other LbL FR coatings for PUF. The insights gained through this research are expected to accelerate the development of other LbL coatings regardless of the intended application.

Ceria nanorods were demonstrated to be an active, bifunctional catalyst for the cyanosilylation of aldehydes. The catalytic activity of ceria was shown to be positively correlated with a decrease in the coordination numbers of neighbouring oxygen atoms around cerium atoms in the catalyst. Chemisorption and density functional theory studies suggested that the coordinatively unsaturated cerium sites exposed by the surface oxygen vacancy defects functioned as Lewis acid sites and the neighbouring oxygen atoms behaved as Lewis base sites in the catalytic cycle.

We designed a stepwise approach for co-sensitization of a zinc porphyrin sensitizer (LD12) with a spirally configured organic dye (CD5) for dye-sensitized solar cells. The co-sensitized LD12 + CD5 device showed significantly enhanced VOC and JSC relative to its individual single-dye sensitized devices. Upon optimization, the device made of the LD12 + CD5 system yielded JSC/mA cm−2 = 16.7, VOC/V = 0.74, FF = 0.73 and η = 9.0%; this performance is superior to that of either individual device made from LD12 (η = 7.5%) and CD5 (η = 5.7%) under the same conditions of fabrication. To understand the effects of the potential shift and charge recombination on the cell performance, we measured charge-extraction (CE) and intensity-modulated photovoltage spectra (IMVS). Upon sensitization with each dye, the TiO2 potentials are similar, but co-sensitization causes the potential to shift down (cathodic shift). Charge recombination was significantly retarded for the co-sensitized system relative to each individual dye-sensitized system, to account for the enhanced VOC for the former relative to the latter. A test of stability indicates a systematic trend between the LD12 + CD5 and LD12 devices; the performance of the co-sensitized device degraded only ∼15% and remained stable during the period of 500–1000 h near 295 K.