Unusual CH₄ dry reforming performance over Ni-based catalyst separated from nickel metal hydride battery waste

The Ni-based compound (s-NiO) has been successfully separated from nickel metal hydride battery waste by a series of acid and base treatments. The catalytic activity of s-NiO reduced to Ni metal was investigated for the CH₄ dry reforming at 780 °C. It was found that the CH₄ conversion over s-NiO was superior to that over regent NiO (r-NiO) and exhibited an unusual behavior. The differences of catalytic activities between s-NiO and r-NiO were examined in terms of carbon deposition and the sinterability of the samples. Carbon deposited by side reactions prevented Ni particles from sintering, and Ni fine particles were highly dispersed on the deposited carbon in the sample obtained from s-NiO.