Tailoring 2D Materials for Enhanced Electrocatalysis: Insights from AFM Imaging and in situ Dynamics

Session

Nanoscale Science of Materials for Energy Storage and Generation

Authors

Professor Mingdong Dong (1)

Affiliations

1. Aarhus University

Keywords

AFM, electrochemical catalysis, operando evolution, 2D materials 

Abstract text

2D materials are highly promising for electrochemical catalysis in oxygen and hydrogen evolution reactions (OER and HER). Surface catalysis plays a crucial role in facilitating these reactions by providing active sites on the catalyst surface where the reaction can occur. Atomic force microscopy (AFM) can provide high-resolution imaging of the surface structure and morphology of 2D materials, allowing for the identification of active sites for catalysis and insight into reaction mechanisms. In this presentation, we introduce a novel top-down process for creating high-density active edge sites on the basal plane of 2D MoS2 through selective etching. This process can tailor the etched structure to create 1D nano-channels, 2D in-plane triangular pits, and 3D vertical hexagonal cavities on the MoS2 basal planes, with distinct crystallographic orientations that are directly monitored by AFM. The etched MoS2 samples show significant enhancement of electrocatalytic activity for HER based on a single entity electrochemical setup.  In addition to AFM observations, we employed in situ electrochemical AFM (EC-AFM) to track the structural dynamics of materials at the nanoscale under OER operation. We used single-layered NiCo LDHs nanosheets as the model system due to their well-defined geometry and impressive OER activity. Through in situ AFM, we were able to observe that water oxidation induces lattice strain on the nanosheets, leading to structural dynamics. Furthermore, we monitored the operando evolution of defective and stacking nanosheets to understand how structural heterogeneity and material interactions. AFM offers a powerful tool for studying and optimizing electrochemical catalysis for renewable energy applications.

 

References

Scanning probe microscopy for electrocatalysis
Y Wang, SA Skaanvik, X Xiong, S Wang, M Dong
Matter 2021 4 (11), 3483-3514

Controllable etching of MoS2 basal planes for enhanced hydrogen evolution through the formation of active edge sites
Z Wang, Q Li, H Xu, C Dahl-Petersen, Q Yang, D Cheng, D Cao, M Dong
Nano Energy 2018 49, 634-643

in situ Tracking Water Oxidation Generated Lattice Strain Effects in Layered Double Hydroxides Nanosheets
Y Wang, X Xiong, S Skaanvik, Z Wang, E Bøjesen, W Liu, M Dong
DOI: https://doi.org/10.21203/rs.3.rs-2486537/