Steam reforming of ethanol over unsupported Ni and Ni–Cu catalysts was investigated. Ethanol and the reaction intermediates like acetaldehyde and acetone are entirely converted into hydrogen and C₁ products at 400°C, while methane steam reforming and reversible water gas shift are the major reactions at higher temperatures. The Ni–Cu catalyst exhibited stable performance during 40h on-stream at 650°C without apparent deactivation, but the Ni catalyst showed severe deactivation only after 12h on-stream due to heavy coke deposition. Filament carbon was mainly produced on the Ni catalyst through the Boudouard reaction, whereas condensed carbon was formed on the Ni–Cu catalyst by methane decomposition.