Engineering Electrocatalytic Microcells for Two-Dimensional Materials

Profiting from intriguing structures and electronic properties, two-dimensional (2D) materials garner increasing attention in energy fields, electrocatalysis in particular. Ultrathin 2D materials possess considerable specific surface area and abundant active sites and are strong candidates for high-activity catalysts. Traditional three-electrode systems reflect the average electrocatalytic properties of multiple samples. As such, it is difficult to accurately understand the electrocatalytic reaction mechanisms and further optimize the electrocatalytic properties of 2D materials. Therefore, establishing microcells to explore the electrocatalytic performance in the microregion is of great practical significance. In this review, recent progress in electrocatalysis in 2D materials explored with microcells is highlighted. This includes the unveiling of active sites and the control of interface behaviors. Two archetypal types of electrocatalytic microcells are discussed, on-chip microcell and scanning electrochemical cell microscopy (SECCM) microcell. Finally, open challenges for the field are discussed.