Vertical Growth of 2D Amorphous FePO4 Nanosheet on Ni Foam: Outer and Inner Structural Design for Superior Water Splitting

at potentials of 1.54 and 1.72 V, respectively, which is comparable to the best bifunctional electrocatalyst reported in the literature. The strategies, introduced in the present work, may open new opportunities for the rational design of other 3D transition-metal-based electrocatalyst through an outer and inner structural control to strengthen the electrocatalytic performance.