Yaron Paz

Ph.D.: Weizmann Institute of Science, 1994

M.Sc.: Chemistry, Weizmann Institute of Science, 1989 

B.Sc.: Chemical Engineering, Technion, 1987 

Main Nano Field:

Utilizing organized organic monolayers, in particular self-assembled monolayers, in photocatalysis and microelectronics.

Research Interests

 Photocatalysis

Characterization and properties of thin and ultrathin films.

Fourier – Transformed Infra-Red Spectroscopy (FTIR)

Our main scientific interest and challenge is to understand how to utilize light in order to efficiently de-contaminate water, air and surfaces and to serve as a source for renewable energy. Accordingly, a variety of aspects related to the use of photocatalysts are under study.

Being based on the strong oxidation potential of the hydroxyl radicals formed on the photocatalyst surface, TiO2 photocatalysis can be expected to have very low selectivity. This lack of sensitivity to the type of contaminants seems to be benevolent at first glance, however it also implies that the photocatalyst does not give any priority to highly hazardous contaminants coexisting with organic contaminants of low toxicity. This shortcoming is further aggravated by the fact that while many low-toxicity contaminants can be degraded by biological means, many of the highly hazardous materials are non-biodegradable. During the last decade we have worked on introducing new means to achieve specificity. In this context, two approaches are under developing: (a) the construction of robust, immobile organic molecular recognition sites (MRS) on inert substrates, located in the vicinity of the photocatalyst. These covalently bound self-assembled molecules physisorb target molecules in a selective manner. Once physisorbed, the target molecules surface-diffuse from site to site towards the interface between the inert domains and the photocatalytic domains, where they are destroyed. (b)  

imprinting the target contaminants at the surface of the photocatalyst during its preparation, thus affecting not only the rate by which the target molecules are degraded, but also the distribution of their end- products.

Coupling between titanium dioxide and inert supports may affect photocatalysis not only through enhancing adsorption, but also by assisting the separation of photogenerated holes from photogenerated electrons.  These phenomena are studied in systems comprising of TiO2 and carbon nanotubes (CNTs), either embedded within polymeric nanofibers made by electrospinning, or within hybrid particles where the CNTs are partially embedded in the particles.

During the last three years we are engaged in an effort to study and develop new materials that have prospects in utilizing light. Along this line we have synthesized and characterized a variety of bismuth-containing ternary oxides and have studied their photocatalytic properties, found to be very promising. We are currently seeking ways to control the surface properties of these materials in order to promote not only photocatalysis but also other closely-related phenomena such as water splitting (hydrogen formation) and photovoltaics.