1. Centre for Advanced Materials Research (CMR), University of Texas at El Paso, 500 W. University Ave., El Paso, Texas 79968, USA
2. Environmental Science and Engineering, University of Texas at El Paso, 500 W. University Ave., El Paso, Texas 79968, USA
3. Department of Electrical and Computer Engineering and Petersen Institute of NanoScience and Engineering, University of Pittsburg, Pittsburgh, Pennsylvania 15261, USA
4. Environmental Molecular Sciences Laboratory (EMSL), Pacific Northwest National Laboratory (PNNL), Richland, Washington 99352, USA
5. Department of Aerospace & Mechanical Engineering, University of Texas at El Paso, 500 W. University Ave., El Paso, Texas 79968, USA