Enlarging the specific surface area and increasing the number of active sites of catalysts have been the key factors to improve the properties of hydrogen evolution reaction (HER) catalysts. Herein, we report a novel remarkable octopus tentacles-like tungsten oxide and carbon coated cobalt oxide (WO3/C@CoO) catalyst on Ni foam (NF) for HER at the first time, which is synthesized via simple hydrothermal process and immersion method. The obtained Ar/H-2-treated WO3/C@CoO/NF catalyst exhibits excellent electrocatalytic activity toward HER with an onset potential of 40mV (vs. RHE) and a Tafel slope of 115mV dec(-1) in 1M KOH, which is significantly better than the Ar-treatedWO3/C@CoO/NF and the CoO/NF NWs. In addition, the prepared Ar/H-2-treated WO3/C@CoO/NF electrode has an outstanding electrocatalytic durability in a long period of stability test for 110 h. Such outstanding property of the Ar/H-2-treated WO3/C@CoO/NF electrocatalyst is attributed to its 3D conductive substitute, carbon coating, strong synergistic effect of between WO3 and CoO and the unique octopus tentacles-like structure making it a very excellent catalyst for hydrogen production. All these experimental results clearly suggest that Ar/H-2-treated WO3/C@CoO/NF electrocatalyst can improve HER catalytic activity and thus has potential practical applications in water splitting. (c) 2018 Elsevier Ltd. All rights reserved.