In this work, we report a vacuum-assisted approach to synthesize tiny Au nanopartciles (Au NPs) entrapped into mesoporous carbon matrix (denoted as Au@MC). The tiny Au NPs are stably entrapped within the mesoporous structure and possess a small particle size (similar to 2.64 nm). The composite also exhibits a high specific surface area (similar to 421 m(2) g(-1)), which may provide convenient transportation and diffusion for substrate molecules. Thus, Au@MC exhibits superior catalytic activity and reusability for 4-nitropheno (4-NP) reduction. The vacuum-assisted synthesis with unique nanostructure is expected to be applied in the preparation of other catalysts. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.