A series of butyric acid (BA)-assisted nickel/alumina catalysts (denoted as XBAN/A) with different butyric acid/Ni molar ratio (X) were prepared by an impregnation method, and they were applied to the hydrogen production by steam reforming of natural gas. All the XBAN/A catalysts exhibited X-ray diffraction patterns indicative of highly stable nickel aluminate phase. However, a XBAN/A catalyst with an appropriate amount of butyric acid showed the enhanced nickel dispersion because of steric hindrance of butyric acid shell surrounding nickel particle. Addition of butyric acid also increased methane adsorption capacity of the catalysts, which was directly related to the catalytic performance. In the steam reforming of natural gas, both natural gas conversion and hydrogen yield showed volcano-shaped trends with respect to butyric acid/Ni molar ratio (X). Nickel dispersion of XBAN/A catalysts was well correlated with natural gas conversion and hydrogen yield over the catalysts. Natural gas conversion and hydrogen yield increased with increasing nickel dispersion. Among the catalysts tested, 0.25BAN/A catalyst with the highest nickel dispersion exhibited the best catalytic performance in the steam reforming of natural gas. (c) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.