Ni films with a thickness of 700-800 nm were deposited on carbon fiber layers using electroless deposition, and Ni films with different porosities and thicknesses were prepared by post-annealing at various temperatures (300, 500, 600, 700, 800 and 900 degrees C). 600 degrees C-annealing under atmospheric conditions resulted in formation of highly porous surface structures with a mean pore size of similar to 100 nm, whereas the other samples showed less or non-porous surface structures. Surface structures and chemical properties of three selected Ni filters annealed at 300, 600 and 900 degrees C (a nonporous Ni filter, a highly porous one, a hollow structured one, respectively) were further studied using XRD, XPS, toluene adsorption and CO oxidation. 600 degrees C-annealed Ni film showed much higher reactivities for toluene adsorption and CO oxidation comparing to other non-porous surfaces. (c) 2012 Elsevier B.V. All rights reserved.