The replacement of fossil resources that currently provide more than 90% of our energy needs and feedstocks of the chemical industry in combination with reduced emission of carbon dioxide is one of the most pressing challenges of mankind. Biomass as a globally available resource has been proposed as an alternative feedstock for production of basic building blocks, which could partially or even fully replace the currently utilized fossil-based ones in well-established chemical processes. The destruction of lignocellulosic feed followed by oxygen removal from its cellulose and hemicellulose content by catalytic processes results in the formation of initial platform chemicals (IPCs). However, their sustainable production strongly depends on the availability of resources, their efficient or even industrially viable conversion processes, and replenishment time of feedstocks. Herein, we overview recent advances and developments in catalytic transformations of the carbohydrate content of lignocellulosic biomass ...

Catalytic Conversion of Carbohydrates to Initial Platform Chemicals: Chemistry and Sustainability

Hydrogen (H2) production via photocatalytic water splitting is one of the most promising technologies for clean solar energy conversion to emerge in recent decades. The achievement of energy production from water splitting would mean that we could use water as a fuel for future energy need. Among the various photocatalytic materials, titanium dioxide (TiO2) is the dominant and most widely studied because of its exceptional physico-chemical characteristics. Surface decoration of metal/non-metal on TiO2 nanoparticles is an outstanding technique to revamp its electronic properties and enrich the H2 production efficiency. Metal dopants play a vital role in separation of electron-hole pairs on the TiO2 surface during UV/visible/simulated solar light irradiation. In this paper, the basic principles, photocatalytic-reactor design, kinetics, key findings, and the mechanism of metal-doped TiO2 are comprehensively reviewed. We found that Langmuir-Hinshelwood kinetic model is commonly employed by the researchers to demonstrate the rate of H2 production. Copper (Cu), gold (Au) and platinum (Pt) are the most widely studied dopants for TiO2, owing to their superior work function. The metal dopants can amplify the H2 production efficiency of TiO2 through Schottky barrier formation, surface plasmon resonance (SPR), generation of gap states by interaction with TiO2 VB states. The recent advances and important consequences of 2D materials, perovskites, and other novel photocatalysts for H2 generation have also been reviewed.

Photocatalytic hydrogen production using metal doped TiO2: A review of recent advances

Carbon and graphene quantum dots (CQDs and GQDs), known as zero-dimensional (0D) nanomaterials, have been attracting increasing attention in sensing and bioimaging. Their unique electronic, fluores...

Review of Carbon and Graphene Quantum Dots for Sensing

▪ Abstract Alginate lyases, characterized as either mannuronate (EC 4223) or guluronate lyases (EC 42211), catalyze the degradation of alginate, a complex copolymer of α-L-guluronate and its C5 epimer β-D-mannuronate Lyases have been isolated from a wide range of organisms, including algae, marine invertebrates, and marine and terrestrial microorganisms This review catalogs the major characteristics of these lyases, the methods for analyzing these enzymes, as well as their biological roles Analysis of primary sequence data identifies some markedly conserved motifs that should help elucidate functional domains Information about the three-dimensional structure of a mannuronate lyase from Sphingomonas sp, combined with various mutagenesis studies, has identified residues that are important for catalytic activity in several lyases Characterization of alginate lyases will enhance and expand the use of these enzymes to engineer novel alginate polymers for applications in various industrial, agricult

ALGINATE LYASE: review of major sources and enzyme characteristics, structure-function analysis, biological roles, and applications.

Finding a viable electrolyte for next-generation 5 V-class lithium-ion batteries is of primary importance. A long-standing obstacle has been metal-ion dissolution at high voltages. The LiPF6 salt in conventional electrolytes is chemically unstable, which accelerates transition metal dissolution of the electrode material, yet beneficially suppresses oxidative dissolution of the aluminium current collector; replacing LiPF6 with more stable lithium salts may diminish transition metal dissolution but unfortunately encounters severe aluminium oxidation. Here we report an electrolyte design that can solve this dilemma. By mixing a stable lithium salt LiN(SO2F)2 with dimethyl carbonate solvent at extremely high concentrations, we obtain an unusual liquid showing a three-dimensional network of anions and solvent molecules that coordinate strongly to Li(+) ions. This simple formulation of superconcentrated LiN(SO2F)2/dimethyl carbonate electrolyte inhibits the dissolution of both aluminium and transition metal at around 5 V, and realizes a high-voltage LiNi0.5Mn1.5O4/graphite battery that exhibits excellent cycling durability, high rate capability and enhanced safety.

Superconcentrated Electrolytes for a High-Voltage Lithium-Ion Battery

A simple and green approach to prepare water-soluble, nitrogen-, sulfur-, and phosphorus-co-doped carbon dots (N/S/P-CDs) by one step hydrothermal treatment of cucumber juice is reported. The resultant N/S/P-CDs possess a uniform morphology, a size of less than 10 nm, plentiful O and N functional groups as well as a limited amount of P and S functional groups, and exhibit good luminescence stability, high resistance to photobleaching, high solubility, and excitation-dependent emission behavior. It was also found that a higher reaction temperature favors the formation of N/S/P-CDs with smaller size and longer wavelength of photoluminescence emissions. Moreover, the N/S/P-CDs can be applied as a fluorescent probe for the detection of Hg2+ ions.

Simple and green synthesis of nitrogen-, sulfur-, and phosphorus-co-doped carbon dots with tunable luminescence properties and sensing application

Understanding of the specific salt effect on the aggregation behavior of ionic liquids (ILs) is relevant to multiple applications. In this work, the influence of a series of 15 salts on the aggregation behavior of [C10mim]Br in aqueous solutions has been investigated by conductivity, fluorescence, and dynamic light scattering. It was shown that NaCl, NaBr, NaI, CH3CO2Na, NaSCN, NaNO3, NaBrO3, NaClO3, C6H5COONa, Na2CO3, Na2SO4, Na2C4H4O6, and Na3CH5O7 have salting-out effect, whereas FeBr3 and AlBr3 have salting-in effect on the aggregation of [C10mim]Br in aqueous solutions. The effect of anions of the added sodium salts on the critical aggregation concentration (CAC), degree of anionic binding (β), and aggregation number (Nagg) of the IL basically follows the Hofmeister series, and the CAC values decrease but the β and Nagg values increase with increasing concentration of the salts. Hydrophobicity of the anions is suggested to play important roles in the salt effect on the aggregation of [C10mim]Br in aq...

Salt Effect on the Aggregation Behavior of 1-Decyl-3-methylimidazolium Bromide in Aqueous Solutions

The emission of NH3 into atmosphere is seriously harmful for human health and public safety, thus the capture and recovery of NH3 from ammonia emissions is highly desirable. In recent years, many kinds of solid adsorbents have been exploited to absorb NH3. However, these materials do not show the advantages of high uptake capacity and good recyclability at the same time. Here, nontoxic and low cost few-layer BiI3 nanosheets have been prepared from bulk BiI3 powder by a simple and efficient liquid phase exfoliation strategy using green solvents and then applied for the NH3 capture for the first time. The results show that the adsorption capacity of NH3 of BiI3 nanosheets reaches up to 22.6 mmol/g at 1.0 bar and 25 °C, which approaches the record value for NH3 adsorption. Importantly, the NH3 uptake in BiI3 nanosheets is completely reversible and no clear loss in uptake capacity is observed after 10 cycles of adsorption-desorption. Furthermore, the BiI3 nanosheets exhibit remarkable selectivity for the separation of NH3/CO2 at 70 °C with theoretical selectivity coefficient of 700, which is promising for the selective separation of NH3 and CO2 in hot tail gas of some industrial processes. Mechanism studies indicate that such superior NH3 capacity, excellent reversibility and remarkable selectivity are primarily attributed to the Bi3+-NH3 coordination interactions.

Exceptional High and Reversible Ammonia Uptake by Two Dimension Few-layer BiI3 Nanosheets.

The nanoplasmonic metal-driven photocatalytic activity depends heavily on the spacing between metal nanoparticles (NPs) and semiconductors, and this work shows that ethylene glycol (EG) is an ideal candidate for interface spacer. Controlling the synthetic systems at pH 3, the composite of Ag NPs with EG-stabilized amorphous TiO2 (Ag/TiO2-3) was synthesized by the facile light-induced reduction. It is verified that EG spacers can set up suitable geometric arrangement in the composite: the twin hydroxyls act as stabilizers to bind Ag NPs and TiO2 together and the nonconductive alkyl chains consisting only of two CH2 are able to separate the two building blocks completely and also provide the shortest channels for an efficient transfer of radiation energies to reach TiO2. Employed as photocatalysts in hydrogen evolution under visible light, amorphous TiO2 hardly exhibits the catalytic activity due to high defect density, whereas Ag/TiO2-3 represents a remarkably high catalytic efficiency. The enhancement mec...

Hucheng Zhang

Papers

Simple and green synthesis of nitrogen-, sulfur-, and phosphorus-co-doped carbon dots with tunable luminescence properties and sensing application

Salt Effect on the Aggregation Behavior of 1-Decyl-3-methylimidazolium Bromide in Aqueous Solutions

Exceptional High and Reversible Ammonia Uptake by Two Dimension Few-layer BiI3 Nanosheets.

Nanoplasmonically Engineered Interfaces on Amorphous TiO2 for Highly Efficient Photocatalysis in Hydrogen Evolution

Hierarchically porous covalent organic frameworks assembled in ionic liquids for highly effective catalysis of C–C coupling reactions