10:30am - 11:00amKeynote
Novel Strategies for Enzyme Immobilization on Nanomaterials
University of Erlangen-Nuremberg, Germany
Enzymes are highly effective and versatile biological catalysts, which display high stereo-, chemo- and regioselectivity while operating under ambient conditions. However, the use of enzymes in their native form is often hindered by their high costs, low operational stability and the difficulties in recovery and reuse. Immobilization of the enzymes onto porous silica supports provides one of the most attractive concepts to overcome these drawbacks . Immobilization often results in improved stability of enzymes under harsh reaction conditions such pH, temperature or organic solvents and enables their facile separation from the reaction media.
Mesoporous silica materials and related inorganic supports are well suited to accommodate large enzyme molecules due to their ordered pore structure, uniform pore size distribution, high specific pore volumes and large internal surface areas. Furthermore, they are water insoluble, thermally, mechanically and chemically stable and resistant towards microbiological attacks.
In this lecture, the encapsulation of different enzymes on a range of porous supports inclusing silica, stainless steel [2[ and ceramics will be discussed with respect to their use as enzymatic catalysts in e.g. the conversion of biomass into sugars.
 M. Hartmann, X. Kostrov, Chem. Soc. Rev., 42 (2013), 6277-6289.
 V.R. Marthala, M. Friedrich, Z. Zhou, M. Distaso, S. Reuss, W. Peukert, W. Schwieger and M. Hartmann, Adv. Funct. Mater. 25 (2015) 1832-1836.
11:00am - 11:30amInvited
Establishing a Reliable Thermochemical Databank with Solution Synthesis Methods
1Rutgers University, United States; 2OLI Systems, Inc, United States; 3University of California Davis, United States
The Critical Materials Institute (CMI) focuses on identifying materials whose scarcity or price instability could endanger existing and future technologies from entering the marketplace. CMI’s current focus is primarily on materials that use rareearth elements (REEs). CMI has a thrust in chemical thermodynamics to create a thermodynamic simulation engine that uses a solution and solidstate databank to assist CMI investigators to design experiments that enable process discovery and optimization more rapidly than through the use of Edisonian methods. Materials synthesis plays an important role in establishing reliable thermochemical data for REEs as well as model validation. Synthetic methods are used to simulate various minerals found in rareearthcontaining rocks and wasteproducts from industrial manufacturing. These materials are used for solubility and calorimetry studies that not only generate thermochemical data but also provide fundamental information about how the REE is incorporated into the rock and mineral.
11:30am - 11:45amOral
Nanocatalysts for Brine Splitting using Continuous Hydrothermal Flow Synthesis
1University College London, United Kingdom; 2Imperial College London, United Kingdom; 3Queen's University Belfast, United Kingdom
Highly active and selective metal oxide nanocatalysts for the light-driven generation of chlorine and hydrogen gases from salt water were produced using continuous hydrothermal flow synthesis (CHFS). This process is presented as an alternative to water splitting and produced valuable chemical feedstocks of chlorine gas, used in a wide range of chemical processes including water purification, and hydrogen gas, which can be stored and used as a fuel or converted to electricity via a fuel cell. CHFS produced materials exhibited increased activity and selectivity when compared to other synthesis methods.
High throughput synthesis and screening methods were used before more detailed electrochemical, photoelectrochemical and structural characterisation methods were carried out on the best performing materials. Synchrotron-based techniques, X-ray absorption spectroscopy and pair distribution function analysis, were used to determine the local atomic structure of the materials and when combined with computational modelling, results suggested that solid solution structures were formed. Solid solutions are expected to be the driving force for the increased selectivity towards chloride oxidation.
Exploration of alternative nanomaterials based on inexpensive, earth-abundant elements are facilitated by applying the understanding of the structure-property relationships and the ability to rapidly produce and screen libraries of materials.
11:45am - 12:00pmOral
Sol-gel Synthesis, Crystal Structure, Electronic, Magnetic Properties in GaxGd2+xZn4-3xO7+δ(0.0 ≤x≤ 0.33) Nano-oxides
Pondicherry University, India
Synthesis of GaxGd2+xZn4-3xO7+δ (S1–S4:x=0.0, 0.11, 0.22, 0.33) nano-oxides are performed by sol-gel method. Powder X-ray diffraction studies show tetragonal phase having lattice parameters: a= 9.8879, 9.8856, 9.8662, 9.8728 Å; c = 6.8343, 6.8362, 6.8477, 6.8559 Å, space group P42/mnm and Z = 2 in S1-S4, respectively. Average crystallite sizes ~ 29-96 nm, ~22-83 nm, ~28-83 nm and ~22-81 nm in S1-S4, respectively indicate nanoparticle formation in the oxides. On refinement of the unit cell structures, agreement factors are lowered to: Rp=0.96, 0.96, 0.96, 0.96 Rwp=0.98, 0.98, 0.98, 0.98; Rexp=0.01, 0.01, 0.01, 0.01 in S1-S4, respectively. Circular contours around the ions indicate significant ionic character in Gd-O and Zn-O bonds. AC electrical conductivity, σac, results in the range 1-10 MHz indicate frequency dependent hopping of Gd3+(4f7)) electrons. DC activation energies, Eg ~0.672, 0.822, 0.803 and 0.799 eV in S1-S4, respectively indicate weakly semiconducting nature of the oxides. Dielectric permittivity, ε′, versus AC frequency plots of S1-S4 show decreasing trend in the higher temperature range ~210-300 oC, while the lower temperature range ~30-190 oC show marginal decrease with frequency from 1 Hz to 10 MHz. Dielectric loss factor, ε′′, increases with increasing temperatures from 30-300 oC at a fixed frequency, f (Hz), and decreases more rapidly for high temperature cases (~110-300 oC) with increasing AC frequencies as compared with the decrease at lower temperature cases (30 - 90 oC) in the samples S1-S4. Magnetic studies show superparamagnetic nature of the oxides at 300 K. Broad optical absorption band ~276 nm is assigned to Gd+3 (4f7) 8S7/2→6IJ (J=1/2, 9/2, 7/2) transitions. Optical energy band gap, Eg, values ~2.82, 2.85, 2.86, and 2.87 eV in S1-S4, respectively are different from Eg values obtained from the DC electrical conductivity data and DFT calculations. These discrepancies are due to the limitations of the techniques used.