Bottom-Up Top-Down Fabrication of Structurally and Functionally Tunable Hierarchical Palladium Materials

Palladium nanomaterials have shown great promise for use in sensing and energy storage devices, and developing simple and inexpensive top-down and bottom-up methods for creating such materials has attracted much attention. In spite of tremendous progress in recent years, creating hierarchical multiscale materials which are dually optimized at the nanoscale for addressing various functional demands and are amenable for micro/macroscale integration into practical devices, remains a challenge. Here we demonstrate a rapid and simple approach based on kinetically-controlled electrochemical deposition and photolithography for creating programmable hierarchical multiscale palladium structures. Through electrochemical methods, we are able to structurally and functionally program palladium materials based on their deposition kinetics. Structures ranging from 2D thin films into 3D globules decorated with nano-needles are created with a tunable hydrogen storage capacity, Raman signal magnitude, and analytical sensitivity. Furthermore, lithography-based methods are used to pattern these programmable structures into highly organized and periodic configurations.