05/17/12

Research - the Big Picture

Hydrogen electrochemistry. The human kind requires renewable energy sources and, in that regard, hydrogen is the ultimate fuel --> hydrogen economy. Electrochemical production of hydrogen through water electrolysis (water supplies are literally unlimited) provides a means of storing electrical energy. Such produced hydrogen can be used in fuel cells to generate electricity and heat. We have been conducting research in hydrogen electrochemistry for over 15 years. Our efforts are related to electrochemical hydrogen generation (water electrolysis), hydrogen storage (pressurized or liquid hydrogen, organic hydrides), hydrogen embrittlement and hydrogen utilization (fuel cells, electrocatalytic hydrogenation). Because electrochemical reactions utilize electrical energy generated via renewable means (hydro electricity, wind power, solar energy, etc.), by their very nature electrochemistry is environmentally friendly and falls into the category of green science and technology.

Electrocatalysis. An industrial-scale electrochemical process is a sequence of atomic level events. We study mechanism and kinetics of electrochemical processes at the atomic/molecular level. We explore alternative reaction pathways and design means of controlling their rates (enhancement = catalysis; reduction = inhibition).

Electro-dissolution of platinum. Platinum is one of the most important electrocatalytic materials. Despite its great corrosion resistance and mechanical stability, it undergoes dissolution under electrochemical conditions --> electro-dissolution. This is of extreme importance to fuel cells which contain supported Pt nanoparticles at which electrochemical reactions take place. We study Pt electro-dissolution in relation to the potential, exposure time and electrolyte composition conditions.

Electrochemical surface and materials science. Electrochemistry provides means of assembling atoms and molecules into functional materials (electrodeposition, electroless deposition, electrochemically driven self-assembly) and means of assessing the stability of materials as a function of pH and E (Pourbaix diagrams) over long periods of time (corrosion science). We study electrochemical formation of thin layers at the atomic level (electrochemical nano-science and nano-technology) and the formation of metallic oxides. We study electro-oxidation (corrosion) with the objective of gaining molecular-level understanding of the processes.

Biocompatible materials and their bio-corrosion. No metallic or composite material lasts for ever. Stable metals such as Ti and its alloys undergo corrosion in the ambient, sea water or body fluids. We study the bio-corrosion in Ti and its alloys in simulated body fluids and artificial saliva.

Research - Details of Specific Projects

Our research focuses on the atomic/molecular level understanding of electrochemical processes taking place at the electrode surface or within its 3-dimensional matrix. Our Research Group studies electrochemical interfacial thermodynamics, electro-adsorption, electro-oxidation of metals, electro-dissolution processes, (bio)corrosion, electrolytic generation of H₂ and O₂, and electrocatalytic hydrogenation of achiral and pro-chiral unsaturated organic compounds. Our Group develops new experimental methodologies and advances existing experimental techniques. Some of the on-going projects are as follows:

• Under-potential deposition of H (UPD H) in the absence/presence of inorganic and organic surface modifiers (catalysts or inhibitors)

• Interfacial thermodynamics of the under-potential deposition of H, Ag, and Cu on M(hkl) electrodes, where M = Pt, Au

• Adsorption and electrocatalytic hydrogenation of unsaturated organic compounds at Pt(hkl) and Cu(hkl) electrodes

• Electro-oxidation and electro-dissolution of Pt, Pd, Ni and Fe

• Electro-dissolution of Pt-based electrocatalysts in acidic media mimicking PEM fuel-cell conditions

• Materials-science and electrochemical characterization of Ni foams

• Application of micrometric and nanometric Ni foams

• Electrochemical quartz-crystal nano-balance (EQCN) and its application to the study of electrochemical interfacial phenomena

• Growth and dissolution of surface oxides at transition metal electrodes (Pt, Au, Pd, Rh, Ni, Fe)

• Electrochemical preparation of colored passive layers on Ti, Zr, and Ti-containing alloys

• Biocompatible Ti-based materials and their applications in orthodontics

• Bio-corrosion of Ti-based alloys

Originality and Outstanding Accomplishments

We pursue in parallel several research avenues. Some projects are "safe", some are experimentally or theoretically demanding, while some might challenge existing paradigms and produce groundbreaking results or can even lead to discoveries. Some of the most original and outstanding accomplishments of our Group are as follows:

• We were the first group to perform very demanding temperature-dependent research on single-crystal Pt electrodes with the objective of determining thermodynamic state functions (DG_ads°, DS_ads°, DH_ads°) for UPD H and the Pt-H_UPD surface bond energy (E_M-Hupd); this line of research was extended to other metals and surface-modifies Pt(hkl) electrodes; in order to determine thermodynamic state functions for UPD H, we developed new theoretical methodology

• We performed very comprehensive research on the electrochemical growth of surface oxides on Pt, Rh, Pd, Au, and Ni; we were the first group to apply the theories developed by N. F. Mott (Nobel Prize for Physics, 1977) and B. E. Conway to surface oxides in order to determine important kinetic and mechanistic parameters; our group advanced the theoretical treatment originally proposed by B. E. Conway

• Our group designed a unique cell for the electrochemical quartz-crystal nanobalance (EQCN) that allows one to study mass variations associated with interfacial phenomena in unprecedented detail; the mass detection limit (currently at ~200 pg cm^-2) and improved vibration isolation system even allow one to monitor sub-monolayer quantities of oxides and mass changes during UPD H

• Our group has performed comprehensive research on the electro-oxidation of Pt using EQCN, CV, and Auger electron spectroscopy (AES); the outcome of this research indicates that OH_ads is not involved in the process and that the electro-oxidation of Pt leads directly to anhydrous PtO

• Our group has developed a unique method of forming brightly colored passive layers on Ti, Zr and Ti-based alloys; we discovered that the coloration can be switched reversibly (the first ever electrochemical multi-color switching effect)

Research Support - Current and Recent Funding

1. NSERC, Discovery Grant - Individual, "Surface Electrochemistry. Adsorption, Reduction, Oxidation and Corrosion Phenomena", Principal Investigator; 2007 - 2012.

2. NSERC, Automotive Partnership Canada, “Strategic Network in Low-Pt PEMFC Research”, Co-Applicant (project led by Prof. S. Holdcroft, SFU); 2011 – 2016.

3. NSERC, Strategic Research Grant, “Design and Integration of Nanostructured Catalyst Layers for PEM Fuel Cells”, Co-Applicant (project led by Prof. M. Eikerling, SFU); 2009 – 2012.

4. Nissan Motor Company, Research Grant, “Investigation of Catalyst Degradation Mechanisms Under Simulated PEMFC Automotive Conditions: Contribution Towards Enhanced Durability, Extended Lifetime and Reduced Cost of PEMFC Stacks”, Principal Investigator; 2010 – 2013.

5. NSERC, Research Tools and Instruments – Category 1, “Electrochemistry Instrumentation for Research on Materials, Interfaces, Electrocatalysts, Photovoltaics and Aqueous Corrosion”, Principal Investigator; 2011 – 2012.

6. NSERC, Research Tools and Instruments – Category 1, “Focused Ion Beam”, Co-Applicant; 2008 – 2009.

7. NSERC, Research Tools and Instruments – Category 1, “Deposition System”, Co-Applicant; 2008 – 2009.

8. Canada Foundation for Innovation and Ministry of Research and Innovation, Ontario, Leaders Opportunity Fund, “Infrastructure for the Search of Quantum Entanglement in Electrochemical Phenomena Involving Hydrogen”, Principal Investigator; 2008 – 2009.