Zeeshan Nawaz

Abstract The dehydrogenation of light alkanes, especially propane and butane, is widely exploited for the large-scale production of corresponding olefins. The industrial application of the direct dehydrogenation of light alkanes is limited due to reaction and thermodynamic constraints. The dehydrogenation of light hydrocarbons involves the breaking of two carbon–hydrogen bonds with the simultaneous formation of a hydrogen and carbon-carbon double bond selectively. It may appear to be simple, but their endothermic nature and selectivity control at higher temperature is difficult. The same technologies with minor changes in process and catalyst were used for the production of both propane and isobutane dehydrogenation. The economic analysis of the available technologies based on the specific consumption of feedstock, operational ease, and capital investment indicates an internal rate of return ~25%. The attractiveness of light alkane dehydrogenation is largely dependent on the difference in feedstock and the price of olefins produced. The available technologies and how they manage reaction constraints at commercial scale have been compared. The possible solution for improvement is by focusing on catalyst improvements and the unique design of reactors.

A highly sensitive amperometric biosensor based on Pt-incorporated fullerene-like ZnO hybrid nanospheres has been investigated. Pt−ZnO nanospheres (PtZONS) with diameters in the range 50−200 nm have been successfully synthesized by electrodeposition on a glassy carbon electrode (GCE). The Pt nanoparticles in ZnO nanospheres have been identified with high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS). The doped Pt nanoparticles demonstrate the abilities to electrocatalyze the oxidation of hydrogen peroxide and substantially raise the response current. The sensitivity of the PtZONS/GCE to hydrogen peroxide is 147.8 μA μM−1 cm−2, which is much higher than that of a conventional electrode. The PtZONS/GCE was functionalized with cholesterol oxidase (ChOx) by physical adsorption. The enzyme electrode exhibits a very high and reproducible sensitivity of 1886.4 mA M−1 cm−2 to cholesterol with a response time less than 5 s and a linear range from 0.5 to 15 μM. Furthermore, it has been revealed that the biosensor exhibits a good anti-interference ability and favorable stability over relatively long-term storage (more than 5 weeks). All these results strongly suggest that the PtZONS not only enhance the sensitivity to cholesterol but also help to eliminate the interference at low applied potential.