Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

A fundamental change has been achieved in understanding surface electrochemistry due to the profound knowledge of the nature of electrocatalytic processes accumulated over the past several decades and to the recent technological advances in spectroscopy and high resolution imaging. Nowadays one can preferably design electrocatalysts based on the deep theoretical knowledge of electronic structures, via computer-guided engineering of the surface and (electro)chemical properties of materials, followed by the synthesis of practical materials with high performance for specific reactions. This review provides insights into both theoretical and experimental electrochemistry toward a better understanding of a series of key clean energy conversion reactions including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The emphasis of this review is on the origin of the electrocatalytic activity of nanostructured catalysts toward the aforementioned reactions by correlating the apparent electrode performance with their intrinsic electrochemical properties. Also, a rational design of electrocatalysts is proposed starting from the most fundamental aspects of the electronic structure engineering to a more practical level of nanotechnological fabrication.

Design of electrocatalysts for oxygen- and hydrogen-involving energy conversion reactions

Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Polydopamine and Its Derivative Materials: Synthesis and Promising Applications in Energy, Environmental, and Biomedical Fields

Bacterial communities incorporating plant-derived carbon in the soybean rhizosphere in Mollisols that differ in soil organic carbon content

Reducing topsoil depth decreases the yield and nutrient uptake of maize and soybean grown in a glacial till

Conventional gas separation membranes made of glassy polymers often exhibit increased segmental motion and reduced selectivity when exposed to high-pressure condensable gases. Decarboxylation cross-linking can effectively improve the plasticization resistance and gas permeability of polymer membranes, but this usually comes at the expense of the gas selectivity. In this work, enhanced π–π interactions and decarboxylation cross-linking are synergistically designed among polymer chains by introducing benzimidazole units and carboxyl side groups into the 6FDA-PABZ:DABA polyimide (PI-Im-COOH). After the thermal treatment, a cross-linked structure was formed through the decarboxylation reaction as confirmed by FTIR spectroscopy and thermal analysis. The π–π interactions between benzimidazole moieties were simultaneously enhanced as proven by WAXD, UV–vis, and fluorescence spectroscopy. The gas separation performance and plasticization resistance of the decarboxylated PI-Im-COOH membranes were enhanced significantly. In particular, the decarboxylated PI-Im-COOH membranes exhibit higher gas selectivities for CO2/CH4 and CO2/N2 gas pairs than the previously reported decarboxylated membranes. The PI-Im-COOH membrane that was thermally treated at 450 °C for 2 h showed outstanding CO2/CH4 separation performance with a CO2 permeability of 685.1 barrer and a CO2/CH4 selectivity of 38.1, surpassing the 2008 Robeson upper bound. The synergistic design of enhanced π–π interactions and decarboxylation cross-linking proves to be a facile strategy to regulate interchain interactions and distances to achieve a high performance for natural gas separation. 

Synergistic Design of Enhanced π–π Interaction and Decarboxylation Cross-Linking of Polyimide Membranes for Natural Gas Separation

In-situ generation of polymer molecular sieves in polymer membranes for highly selective gas separation

The availability of water has an important role in soybean production. The researches on the effects of short-term water stress on nodule formation and development of soybean (Glycine max (L.) Merr.) at the key nodulation stage were limited. In this study, a pot experiment was carried out to check the response of nodulation and growth of two soybean cultivars (Hefeng 50 and Kenfeng 16) to drought and flooding. Both soybean cultivars were subjected to water stress at the flowering, pod bearing and grain filling stages for 10 days. The results showed that the drought decreased the biomass of shoots and roots, while flooding inhibited root growth and increased shoot biomass. The carbon contents in root and nodule were decreased by drought and flooding, as a result, this affected nodule formation and development. Drought and flooding during the flowering stages affected primarily nodule formation, as nodule number decreased in drought compared to control. Nodule development was significantly affected by water stress at pod bearing stages. Especially at pod bearing stage with drought, nodule dry weight was decreased by 41% and 21% for Hefeng 50 and 21% for Kenfeng 16 compared to control, while 75% for Hefeng 50 and 74% for Kenfeng 16 suffered drought stress. The stage of water stress had different influence on soybean grain yield, the decrease ranging from 11% to 69% for drought, while from 15% to 44% for flooding compared to control. These results demonstrated that the adjustment of water condition and stress stage can vary nodulation in soybean, and further affect seed yield.

Jian Jin

Papers

Bacterial communities incorporating plant-derived carbon in the soybean rhizosphere in Mollisols that differ in soil organic carbon content

Reducing topsoil depth decreases the yield and nutrient uptake of maize and soybean grown in a glacial till

Synergistic Design of Enhanced π–π Interaction and Decarboxylation Cross-Linking of Polyimide Membranes for Natural Gas Separation

In-situ generation of polymer molecular sieves in polymer membranes for highly selective gas separation

Effects of short-term drought and flooding on soybean nodulation and yield at key nodulation stage under pot culture