Hindawi Publishing Corporation Journal of Nanomaterials Volume 2013, Article ID 542753, 6 pages http://dx.doi.org/10.1155/2013/542753 Research Article Hydrogen Adsorption Properties of Nano- and Microstructures of ZnO Rizwan Wahab, 1 Farheen Khan, 2 Naushad Ahmad, 3 Hyung-Shik Shin, 4 Javed Musarrat, 5 and Abdulaziz A. Al-Khedhairy 1 1 Department of Zoology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia 2 Department of Chemistry, Aligarh Muslim University, Aligarh, Uttar Pradesh 202002, India 3 Department of Chemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia 4 Energy Materials & Surface Science Laboratory, Solar Energy Research Center, School of Chemical Engineering, Chonbuk National University, Jeonju 561-756, Republic of Korea 5 Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh 202002, India Correspondence should be addressed to Rizwan Wahab; rwahab@ksu.edu.sa Received 16 May 2013; Revised 31 August 2013; Accepted 10 September 2013 Academic Editor: Xuedong Bai Copyright © 2013 Rizwan Wahab et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Nanoparticles, microfowers, and microspheres of zinc oxide have been synthesized in a large quantity via solution process at low temperature and were tested for the hydrogen adsorption studies. Te experiments were carried out using Sievert’s apparatus which resulted in highest hydrogen adsorption value for nanoparticles is ∼1.220 wt%, whereas for microfower composed with thin sheets value reduced (∼1.011 wt%) but in case of microspheres composed with nanoparticles having below one wt% (∼0.966 wt%). Te FE-SEM and XRD clarify that the obtained products are crystalline with wurtzite phase. Including morphological and crystalline characterization, the surface area of the prepared nano- and microstructures was observed with BET. 1. Introduction Hydrogen (H 2 ) is the most valuable and convenient energy source, which holds tremendous properties due to its high energy density. It is a clean, environmental friendly versatile source of energy that can be transformed to a desired form, without releasing harmful emissions [1, 2]. Since it is free from air pollution and greenhouse gas therefore, attracted a great deal of attention towards a green energy regime [1, 2]. Analyses have concluded that “most of the hydrogen supply chain path releases signifcantly less carbon dioxide into the atmosphere than the gasoline used in the hybrid electric vehicles” and thus leads to the signifcant reduction in carbon dioxide emission. Te mass and volume density problems associated with hydrogen/molecular hydrogen storage are the current barrier to practical storage schemes. Te properties of hydrogen storage in materials were assessed for auto- motive applications, due to its low cost, high gravimetric and volumetric density, fast kinetics, proper thermodynamics and low temperature dissociation/decomposition properties, and long-term stability. Numerous metal hydrides, chemical hydrides, adsorbents, and the nanomaterials have been used for hydrogen storage purposes [3–9]. Till date, the fulfllment of hydrogen storage criteria from these materials does not reach their high H 2 content. Te hydrogen content is very less and it is below 6 wt% [10]. Nanostructured materials have potential capacity due to their high surface area and adsorption properties on the surface and can easily infuence thermo dynamics and kinetics of hydrogen adsorption [9, 10]. It can ofer the possibility of controlling and tailoring the parameters independently of their bulk counterparts. Due to high surface area it ofers various advantages for the physico- chemical reactions such as surface interactions, adsorptions, rapid kinetics, low-temperature sorption, hydrogen atom dissociation, and molecular difusion via the surface catalyst [9, 10]. Several reports have been published to explore the approaches on to absorb molecular hydrogen onto a solid storage material. CNTs are recently studied for hydrogen storage purpose due to its excellent physical, chemical, and electronic properties [1, 2]. Te hydrogen adsorption capacity