Chang Hwan Kim Assistant Research Scientist of Hydrogen Energy Technology Laboratory and Chemical Engineering 3086 H. H. Dow (734) 647-9707 Fax: (734) 763-0459 chkm@umich.edu Surface Science and Catalysis, fuel processing for hydrogen production, diesel emission control nanostructured gold based catalysts, microchannel catalytic reactor Short Bio Research Publications

Research Interests

Microscale Fuel Processors for H2 Generation:
A key challenge to the commercialization of PEM Fuel Cell is the lack of sufficiently small and inexpensive fuel processors to convert hydrocarbons like gasoline into H2. Significant improvements to existing fuel processor technologies will be achieved by integrating low-cost micro-channel systems, high performance catalysts. This micro-channel derived system will allow: (1) efficient thermal coupling of the fuel processor components and elimination of some heat exchangers, (2) optimization of reactor temperature profiles and minimization of the catalyst bed sizes, and (3) better cold start and transient responses.
Models developed here will take into account many effects that are normally neglected at larger scales. Factors such as the diffusion length and wall effects are normally omitted from the models for conventional macro-scale systems. The geometry and flow patterns was designed to maximize the rate of reaction and heat efficiency by constructing the reactor in the form of a micro heat exchanger. The micro-channel technology also provides the modular and flexible design that enables rapid system integration.

Supported Gold Catalysts:
Since Haruta’s discovery that catalysts containing nano-sized gold particles possess extraordinary activities for reactions including CO oxidation and water gas shift, there has been substantial interest in their use and the origin of their exceptional catalytic properties. Their performance is directly linked with preparation methods such as deposition-precipitation method. The support also appears to play an important role, in that the most active water gas shift (WGS) catalysts have typically employed reducible oxide supports like Fe2O3 and CeO2. While these oxides alone do not possess significant catalytic activities, the redox and oxygen storage properties appear to be important in catalyzing a bifunctional mechanism for WGS catalysis over supported gold catalysts.
Our research is focusing on development of highly active and stable nano-scaled gold WGS catalysts and investigation of potential use of gold catalysts in industrial applications.

Reformate Assisted NOx SCR Catalysts:
An emerging application is as a reductant for on-board removal of NOx emissions from diesel engines. Because hydrogen has the highest energy density of any non-nuclear fuel, can be converted to electrical or thermal energy via highly efficient, non-polluting processes, and can be easily distributed, it also holds great promise as a sustainable fuel. We have developed new, nanostructured catalysts that are effective for the production of hydrogen from water and biofuels including biodiesel and ethanol, and the Selective Catalytic Reduction (SCR) of NOx with hydrogen under lean-burn conditions. These catalysts will reduce the size and cost of the associated reactors.