Amorphous nickel–boron alloys supported on α-alumina (NiB/Al2O3) and on titania-modified α-alumina (NiB/TMA) with titania loadings ranging from 1·25 to 10 wt% were prepared by a reductive impregnation method, which resulted in a highly dispersed NiB amorphous alloy on the support. When used as catalysts for partial hydrogenation of cyclopentadiene to cyclopentene in a flow fixed-bed reactor at atmospheric pressure, the NiB/Al2O3 showed higher activity than Ni/Al2O3 and Pd/Al2O3 but the NiB/TMA with 5 wt% of titania loading (NiB/TMA5) showed the highest activity of all for the production of cyclopentene in a temperature range of 80–200°C with 10 g gcat−1 h−1 of cyclopentadiene feed. The maximum yield of cyclopentene was 97% on NiB/TMA5, 92% on NiB/Al2O3, 60% on Ni/Al2O3 and 23% on Pd/Al2O3, respectively. The catalytic stability of the amorphous NiB/TMA5 was also excellent with time on stream. The catalyst samples were characterized by ICP, XRD, XPS, BET, TEM and O2 adsorption. The probable modification mechanism is discussed. © 1998 SCI