RESEARCH ARTICLE Copyright © 2013 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Nanoscience and Nanotechnology Vol. 13, 2613–2623, 2013 Development of Nanoporous Structure in Carbons by Chemical Activation with Zinc Chloride Rinita Rajbhandari 1 , Lok Kumar Shrestha 2 ∗ , Bhadra Prasad Pokharel 1 , and Raja Ram Pradhananga 3 1 Department of Science and Humanities, Institute of Engineering, Tribhuvan University, Pulchowk Campus, Kathmandu, 44613, Nepal 2 International Center for Materials Nanoarchitectonics WPI-MANA, National Institute for Materials Science (NIMS), 1-1 Namiki, Ibaraki Tsukuba, 305-0044, Japan 3 Central Department of Chemistry, Tribhuvan University, Kathmandu, 44613, Nepal Series of activated carbons (ACs) have been prepared from Lapsi (Choerospondias axillaris) seed powder (LSP) by chemical activation with zinc chloride (ZnCl 2 ) and the effects of ZnCl 2 impregna- tion ratio, carbonization time, and precursor sources on the structure and properties of ACs have been systematically investigated. Carbonization was carried out at 400  C and the ratio of LSP and ZnCl 2 was varied from LSP:ZnCl 2 = 1:0.25 (AC-0.25), 1:0.50 (AC-0.50) 1:1 (AC-1), 1:2 (AC-2), and 1:4 (AC-4). The ACs were characterized by Fourier transform-infrared (FTIR) spectroscopy, Raman scattering, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Surface properties (effective surface areas, pore volumes, and pore size distri- butions) were studied by nitrogen adsorption–desorption measurements. The electrochemical and vapor sensing properties were investigated by cyclic voltammetry, and quartz crystal microbalance (QCM) method, respectively. All the ACs are amorphous materials containing oxygenated surface functional groups and having nanoporous (microporous and mesoporous) structures. We found that surface properties depend on the LSP:ZnCl 2 ratio, carbonization time, and also on the precursor type. The effective surface area increased significantly with increasing LSP:ZnCl 2 ratio from 1:0.25 to 1:0.5 and then remain apparently constant. However, total pore volume increased continuously with ZnCl 2 ratio. Increase in the carbonization time above 4 h decreased both the surface area and pore volume. ACs prepared from bamboo and coconut shell showed better surface properties compared to AC prepared from sugarcane; surface area and pore volume of the former systems are nearly double of the later system. AC derived from LSP (AC-4) showed excellent electrochemi- cal performance giving specific capacitance value of 328 F/g in 1 M H 2 SO 4 solution demonstrating the potential use of this material for supercapacitor electrodes. Our ACs showed good capability of molecule sensing of toxic solvent vapors such as carbon tetrachloride and pyridine. Keywords: Lapsi (Choerospondias axillaris) Seed Powder, Nanoporous Activated Carbon, Zinc Chloride Activation, Electrochemical Properties, Vapor Sensing. 1. INTRODUCTION Recent developments in nanoscience and nanotechnology are expected to produce innovative advanced functional materials with advanced properties and smart functions, which can be utilized successfully for the production of extremely efficient solar cells and energy storage devices. Such materials would be of great benefit to the human society and also advantageous to resolve the current issues on environmental and energy problems. However, ∗ Author to whom correspondence should be addressed. advanced techniques available so far have mostly been applied in synthetic approaches to macroscopic mate- rials and production of functional materials based on atom/molecular technology has not yet fully developed. To overcome this technological problem, establishment of a novel concept, which is able to construct novel func- tional materials from atomic/or molecular units has been long awaited. Although significant efforts have been made to synthesize various nanomaterials; nanoparticles in differ- ent length scale and having diverse morphologies, sheets, tubes etc., their individual functions are limited com- pared with the huge potential available from integrated J. Nanosci. Nanotechnol. 2013, Vol. 13, No. 4 1533-4880/2013/13/2613/011 doi:10.1166/jnn.2013.7373 2613