Laboratory for Low Carbon Energy and Sustainable Environment  
     
  Research  
     
  1. Photocatalytic Reduction of CO2 to Fuels by Sunlight  
     
 
The goal of this research project is to effectively produce solar fuels by using CO2 and water as building blocks and novel TiO2 nanocomposites as photocatalysts. The climate change due to increased greenhouse gas concentrations in the atmosphere has revealed the urgent need to control CO2 emissions. Instead of sequestering the huge amount of CO2 in geological formations, using solar energy to recycle CO2 offers a brand new opportunity for simultaneous reduction of CO2 and production of energy-bearing compounds (e.g. syngas, methane, and methanol) that can be processed to liquid transporation fuels. We are developing nanostructured TiO2-based photocatalysts that can dramatically increase the efficiency of CO2 conversion to fuels by facilitating photoinduced charge transfer and improving utilization of the visible light. Recently, we have developed a hybrid adsorbant/photocatalyst material that can effectively adsorb and convert CO2 at a moderately-elevated temperature (150 C) with high catalytic stability, which is promising for power plant flue gas CO2 emission control.
 
     
  2. Advanced Electrode Materials for Lithium-Ion and Lithium-Sulfur Batteries  
     
 

Lithium secondary batteries are considered the most promising energy storage technology for emerging large-scale applications such as for hybrid, plug-in hybrid, and electric vehicles, and for smoothing out the intermittency of wind and solar power. However, fundamental improvements in lithium ion batteries (LIBs) s are needed to meet the demanding requirements for power, safety, cycle life, cost, etc. To improve the battery performance, it is essential to advance the electrochemical properties of electrode (anode and cathode) materials. TiO2 and LiMn2O4 are promising materials for anode and cathode, respectively. In this project, we are advancing the structure and composition of the electrode materials with the goal of achieving low-cost and high-performance LIBs.

Lithium-sulfur (Li-S) batteries holds great promise for achieving the goal of EV applications because of the very high theoretical energy density of sulfur. The major obstacle is the low electrical conductivity of sulfur and the dissolution of polysulfides in the electrolyte during cycling. In this project, we have designed a novel multi-modal porous carbon/sulfur microsphere as the cathode material using a simple and inexpensive method. The unique combination of macropores, mesopores and micropores has led to a high electrochemical performance.

 
     
  3. Novel Nanofiber Membranes for Water and Wastewater Treatment  
     
 
This project focuses on fabricating and testing novel hybrid nanofiber materials and resultant membranes for concurrent filtration of fine particles and removal of multi-pollutants in water. Heavy metals (e.g., As, Cr) are removed through adsorption, while TOC (e.g., humic acid) and micro-contaminants (e.g. endocrine disruptors, pharmaceuticals) are decomposed upon photo-illumination.? The hybrid materials have unique features of high surface area, high adsorption capacity, and ability of anti-fouling and on-site regeneration. They are advantageous over benchmark activated carbon adsorbents that are ineffective for heavy metal removal and suffer from capacity loss over regeneration cycles.
 
     
  4. Mercury Emission Control from Coal Combustion Flue Gas  
     
 
Mercury is a toxic air pollutant and coal-fired power plants are currently the largest source of mercury emissions in the United States. Conventional mercury control technology is costly by using activated carbons to adsorb mercury present in the coal combustion flue gas. We have developed a novel vanadia-titania-silica catalyst that can effectively oxidize elemental mercury so that the oxidized mercury species can be captured by electrostatic precipitators or be scrubbed away by wet scrubbers equipped in the power plants. Current focus is to understand the mechanism of catalytic mercury oxidation and reaction kinetics under flue gas conditions.
 
     
  5. Nanomaterial Synthesis and Characterization  
     
 
In our laboratory, we are using various methods to synthesize nanomaterials such as sol-gel method, hydrothermal method, and aerosoal assisted methods. Material characterization includes XRD, BET, UV-vis, SEM, TEM, HRTEM, EDX, XPS, etc. These nanomaterials are successfully applied in the above described research projects.
 
     
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