This work explores the deposition of Pt monolayers on 3D graphene and 2D MoS₂ as catalyst architectures for electrocatalysis. Ni foam was utilized as a starting substrate for the 3D graphene growth before Pt was deposited layer-by-layer in a surface-limited electrochemical scheme to achieve highly wetted and atomically thin growth. A similar surface-limited technique was utilized for the deposition of Pt on both vertically and horizontally aligned MoS₂. High resolution TEM, XPS, SEM/EDX, and electroanalytical techniques were used to characterize these samples and reveal the evolution of the atomic/electronic structure as a function of the number of Pt monolayers. Specifically, the ORR and the HER reactions were used to characterize the catalytic activities of the graphene- and the MoS₂-templated catalysts, respectively. It is demonstrated that the synthesis scheme outlined here allows for the design of dimensionally-controlled and ligand-flexible catalyst architectures that can have a wide range of chemical applications.