Preparation of Zirconium Phosphate Nanomaterials and Their Applications as Inorganic Supports for the Oxygen Evolution Reaction

Zirconium phosphate (ZrP) nanomaterials have been studied extensively ever since the preparation of the first crystalline form was reported in 1964. ZrP and its derivatives, because of their versatility, have found applications in several fields. Herein, we provide an overview of some advancements made in the preparation of ZrP nanomaterials, including exfoliation and morphology control of the nanoparticles. We also provide an overview of the advancements made with ZrP as an inorganic support for the electrocatalysis of the oxygen evolution reaction (OER). Emphasis is made on how the preparation of the ZrP electrocatalysts affects the activity of the OER.

BLACK AND WHITE LAHAR AS INORGANIC SUPPORT FOR THE IMMOBILIZATION OF YEAST INVERTASE

Volcanic ejecta or lahar can serve as an inorganic support for the immobilization of invertase. Pampanga and Bicol lahar samples were pretreated by ignition at 550oC for 5 hrs followed by concentrated hydrochloric acid treatment, activatedby reaction with aminopropyltriethoxysilane (APTS) and then covalently bound to invertase using glutaraldehyde as linker. Chemical tests confirmed the attachment of APTS to lahar and glutaraldehyde to silanized lahar. The quantity of immobilized invertase on Pampanga white, Pampanga black and Bicol black lahar were 98.73%, 96.73% and 84.27%,respectively. Conditions for maximum activity of invertase immobilized on Pampanga white lahar were pH 3.5, 45oC and 0.3 M sucrose concentration. The Kmand Vmaxfor free invertase and immobilized invertase on Pampanga white lahar were 2.37 M and 48.75 mmol/min, and 3.88 M and 38.87 mmol/min, respectively. Invertase bound to Pampanga white lahar was most stable towards repeated and continuous use and towards storage with intermittent use as indicated by its relatively greater activity.

A study of biocatalysts based on glucose oxidase

During this work, we studied the possibility of glucose oxidase (GOx) covalent immobilization on a modified inorganic support. A series of GOx-based biocatalysts was synthesized by crosslinking the enzyme to a surface of modified silica or alumina. Polyelectrolyte layers were used as modifiers for the silica and alumina surfaces. These layers promote tight binding of the GOx to the support. The biocatalyst’s activity and stability were studied using an oxidation reaction of d-glucose to d-gluconic acid. It was found that GOx immobilized on the modified SiO2 using glutardialdehyde as a crosslinking agent was the most active and stable catalytic system, showing an 85% yield of gluconic acid. A study of the synthesized biocatalyst structure using FTIR spectroscopy showed that the enzyme was covalently crosslinked to the surface of an inorganic support modified with chitosan and glutardialdehyde. In the case of SiO2, the quantity of the immobilized enzyme was higher than in the case of Al2O3.

High yield, controlled synthesis of graphitic networks from dense micro emulsions

We propose a new synthesis method to produce hyper-branched carbon nano structures that we call carbon nano networks. These porous, graphitic materials directly grow into a networked structure, do not require the use of an inorganic support, and can be tailored by experimental conditions to better suit their application.

Organic/Inorganic Support for Immobilizing Cp2ZrCl2/ TiCl4 Hybrid Catalyst to Prepare Bimodal Polyethylene

Organic/inorganic support for immobilizing hybrid catalyst (Cp2ZrCl2/ TiCl4) was devised. Silica was the inorganic part using in the immobilization of Cp2ZrCl2. Subsequently, styrene and acrylic copolymer (PSA) was coated on the silica. TiCl4 was finally supported on the PSA. PSA layer played obvious barrier ability to triethylaluminium (TEA) in the support which was observed by ethylene polymerization. This outstanding barrier property dramatically restrained the toxic effect of TEA to Cp2ZrCl2. Thus, the property of Cp2ZrCl2 could be maintained using cocatalyst TEA. Bimodal polyethylene was achieved cocatalysted by TEA.