Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

The detection methods and generation mechanisms of the intrinsic reactive oxygen species (ROS), i.e., superoxide anion radical (•O2–), hydrogen peroxide (H2O2), singlet oxygen (1O2), and hydroxyl radical (•OH) in photocatalysis, were surveyed comprehensively. Consequently, the major photocatalyst used in heterogeneous photocatalytic systems was found to be TiO2. However, besides TiO2 some representative photocatalysts were also involved in the discussion. Among the various issues we focused on the detection methods and generation reactions of ROS in the aqueous suspensions of photocatalysts. On the careful account of the experimental results presented so far, we proposed the following apprehension: adsorbed •OH could be regarded as trapped holes, which are involved in a rapid adsorption–desorption equilibrium at the TiO2–solution interface. Because the equilibrium shifts to the adsorption side, trapped holes must be actually the dominant oxidation species whereas •OH in solution would exert the reactivity...

Generation and Detection of Reactive Oxygen Species in Photocatalysis

A review on g-C3N4-based photocatalysts

Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

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Carbon capture and storage (CCS): the way forward

Hydrogen fuel is considered as the cleanest renewable resource and the primary alternative to fossil fuels for future energy supply. Sustainable hydrogen generation is the major prerequisite to realize future hydrogen economy. The electrocatalytic hydrogen evolution reaction (HER), as the vital step of water electrolysis to H2 production, has been the subject of extensive study over the past decades. In this comprehensive review, we first summarize the fundamentals of HER and review the recent state-of-the-art advances in the low-cost and high-performance catalysts based on noble and non-noble metals, as well as metal-free HER electrocatalysts. We systemically discuss the insights into the relationship among the catalytic activity, morphology, structure, composition, and synthetic method. Strategies for developing an effective catalyst, including increasing the intrinsic activity of active sites and/or increasing the number of active sites, are summarized and highlighted. Finally, the challenges, perspectives, and research directions of HER electrocatalysis are featured.

Recent Advances in Electrocatalytic Hydrogen Evolution Using Nanoparticles.

A series of BaCe0.8 − x
 Zr
 x
 Y0.2O3 − δ (BCZYx) (x = 0, 0.2, 0.4, 0.6, 0.8) powders were prepared by EDTA–citrate complexing sol–gel process in this paper. The electrical conducting behavior, as well as chemical stability, was investigated. X-ray diffraction (XRD) results reveal that all samples are homogenous perovskite phases. Observed from XRD patterns and thermogravimetric curves, the samples with x ≥ 0.4 survive in the pure CO2, while samples with various Zr contents all present structurally stable against steam at 800 °C. The Zr-free sample of BaCe0.8Y0.2O3 − δ possesses the maximum bulk conductivity, 4.25 × 10−2 S/cm, but decomposes into Ba(OH)2 and Ce0.8Y0.2O3 − δ in steam. A negative influence of increasing Zr content on the conductivity of BCZYx can be observed by impedance tests. Considering the effect of temperature on the bulk conductivity, BCZY0.4 is preferred to be applied in SOFC as a protonic conductor, ranging from 1.52 × 10−4 to 1.51 × 10−3 S/cm (500–850 °C) with E
 a = 0.859 eV, which is proved to be a good protonic conductor with t
 H+ ≥ 0.9.

The chemical stability and conductivity improvement of protonic conductor BaCe0.8 − xZrxY0.2O3 − δ

For the first time, novel single-phase octahedral Bi3(FeO4)(WO4)2 (BFW) nanocrystals, as a visible-light-induced catalyst, had been successfully synthesized in a facile alkaline hydrothermal way without using any template. Scanning electron microscopy (SEM) images clearly show single crystals of BFW with regular octahedral morphology. The formation of the single-phase BFW compound was recorded using an X-ray diffraction (XRD) technique. The optical property of BFW was investigated using ultraviolet–visible light (UV-vis) spectra. The band-gap energy of BFW was revealed to be 1.98 eV. More importantly, the interfacial interaction of W6+ ions substituted by Fe3+ ions was confirmed. Moreover, the present study pointed out the positions of the valence band and the conduction band. Compared with the Bi2WO6 (BW) sample, BFW exhibited superior photocatalytic degradation activity of the Rhodamine B (RhB) under visible-light irradiation. A trapping experiment was conducted to further illustrate that hydroxyl radic...

Hydrothermal Synthesis of Novel Uniform Nanooctahedral Bi3(FeO4)(WO4)2 Solid Oxide and Visible-Light Photocatalytic Performance

Interaction between electrode materials Sr2FeCo0.5Mo0.5O6−δ and hydrogen sulfide in symmetrical solid oxide fuel cells

A core–shell catalyst for SCR reaction, which consists of Fe-ZSM-5 core and meso-SiO2 shell, was synthesized by the step by step assembly method. The cerium species were introduced into the SiO2 shell by using different solvents to enhance the oxidation of NO, which is beneficial to the fast-SCR reaction. The meso-SiO2 shell inhibits the growth of CeO2 particles and enhances the dispersion of cerium oxide. The results of TEM, XPS and H2-TPR found that the higher dispersity and smaller size of cerium species endow catalyst with a high ration of Ce4+/Ce3+ and outstanding SCR activity. In addition, the evolution and role of chemisorbed and lattice oxygen were investigated by in situ DRIFTS and O2-TPD. The meso-SiO2 shell inhibits the growth of CeO2 particles and enhances the dispersion of cerium oxide, effectively increasing the activity of the SCR reaction.

The Effect of CeO2 Dispersity and Active Oxygen Species on the SCR Reaction Over Fe-ZSM-5@Ce/meso-SiO2

Cu-BTC–ethylenediamine (EDA)/polyethyleneimine (PEI) adsorbents were synthesized using a protophilic solvent-assisted solvothermal method. EDA was introduced to enhance the degree of activation due to its lower boiling point allowing it to be removed easily compared with dimethylformamide. A contrast experiment was done by introducing PEI to the solvothermal solution considering its higher boiling point. Powder X-ray diffraction, scanning electron microscopy and Raman spectroscopic characterizations were performed to investigate the effect of EDA/PEI on crystallinity and morphology of the adsorbents. 1H NMR characterization and elemental analysis were performed to study the removal rate of organic guest molecules and the degree of activation. Nitrogen physical adsorption and CO2 adsorption isotherms were used to measure the surface area and CO2 adsorption capacities. The CO2 adsorption mechanism of the synthesized adsorbents is mainly dependent on physisorption determined by surface area. Furthermore, open metal sites generated by the enhancement of degree of activation also promote the CO2 adsorption performance. Therefore, adsorbents synthesized using the protophilic solvent-assisted solvothermal method exhibit excellent CO2 adsorption performance. Copyright © 2015 John Wiley & Sons, Ltd.

Qin Zhong

Papers

The chemical stability and conductivity improvement of protonic conductor BaCe0.8 − xZrxY0.2O3 − δ

Hydrothermal Synthesis of Novel Uniform Nanooctahedral Bi3(FeO4)(WO4)2 Solid Oxide and Visible-Light Photocatalytic Performance

Interaction between electrode materials Sr2FeCo0.5Mo0.5O6−δ and hydrogen sulfide in symmetrical solid oxide fuel cells

The Effect of CeO2 Dispersity and Active Oxygen Species on the SCR Reaction Over Fe-ZSM-5@Ce/meso-SiO2

A protophilic solvent-assisted solvothermal approach to Cu-BTC for enhanced CO2 capture