While electrochemical water splitting is one of the most promising methods to store electrical energy in chemical bonds, facile fabrication of transition metal electrocatalyst materials with judicious chemical and structural design to facilitate high electrochemical reactivity with an in-built gas bubble release mechanism is currently lacking. Here, a facile pseudomorphic-phase transformation of a diversified ternary NiCo hierarchical structure is demonstrated. Essentially, a universal template of hydroxide derivatives facilitates successive pseudomorphic-phase transformation with structural framework preservation. Direct growth of integrated 2D nanosheet-1D nanowire hierarchical features onto a conductive electrode leads to strong interfacial contact and an extended platform for electrolyte accessibility as well as provision of a discontinuous surface for low adhesion gas bubble evolution. Collectively, the as-prepared mixed transition metal and multi-dimensional structured electrode presents a uniquely advantageous electrochemical energy conversion material design.