Materials for Energy, Drug, and Information Storage

Author

Peifu Cheng, Michigan Technological UniversityFollow

Date of Award

2015

Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy in Environmental Engineering (PhD)

Administrative Home Department

Department of Materials Science and Engineering

Advisor 1

Yun Hang Hu

Committee Member 1

Jiann-Yang Hwang

Committee Member 2

Feng Zhao

Committee Member 3

Kazuya Tajiri

Abstract

It is generally recognized that H₂O adsorption on a porous material would inhibit H₂ adsorption. However, Chapter 3 reports that stable H₂O-functionalized ZIF-8(a representative MOF), which was obtained by the simple water treatment of ZIF-8 at ambient temperature, can increase its H₂ adsorption heat from 5.2 to 10.1 kJ/mol. As a result, the reversible H₂ capacity at ambient temperature increased by 77%.

A suitable isotherm equation for C₂H₂ adsorption on various MOFs has not been found. Chapter 4 demonstrates that Dubinin-Astakhov equation can be exploited as a general isotherm model to depict C₂H₂ adsorption on MOF-5, ZIF-8, HKUST-1, and MIL-53. Furthermore, it was found that the adsorption of C₂H₂ on the defected MIL-53 is stronger than that on MIL-53 without defection, reflected by adsorption-heat increase from 19.3 to 25.1 kJ/mol.

Chapter 5 finds that the adsorption of CO₂ on the defected ZIF-8 is stronger than that on ZIF-8 without defection, reflected by initial adsorption-heat increase from 16.0 to 22.8 kJ/mol. As a result, the specific reversible CO₂ capacity per surface area increased with increasing defects.

A novel strategy was developed to enhance the hydrophilicity on the external surface of ZIF-8 without reducing or blocking the internal pores in Chapter 6. A simple ball-milling approach combined with water treatment results in a significantly higher cell viability without compromising its hydroxyurea loading and release capacity.

It’s a challenge to build a memristor with odd-symmetric I–V features. In Chapter 7, a novel strategy, in which two same asymmetric switch components can be combined as a symmetric device, is reported to create an odd-symmetric memristor. Furthermore, with this strategy, the surface-sulphurization was performed on both sides of a Ag foil, leading to a Ag₂S/Ag/Ag₂S odd-symmetric memristor consisting of two asymmetric Ag₂S/Ag memristive switches.

Chapter 8 demonstrate that 2H phase of bulk MoS₂ possessed an ohmic feature, whereas 1T phase of exfoliated MoS₂ nanosheets exhibited a unique memristive behaviour due to voltage-dependent resistance change. Furthermore, an ideal odd-symmetric memristor with odd-symmetric I–V characteristics was successfully fabricated by the 1T phase MoS₂ nanosheets via combining two asymmetric switches anti-serially.

Recommended Citation

Cheng, Peifu, "Materials for Energy, Drug, and Information Storage", Campus Access Dissertation, Michigan Technological University, 2015.

https://doi.org/10.37099/mtu.dc.etdr/12