Week 10
Speaker: Sayan Banerjee
Title: On the Critical Role of Surface Reconstruction, Molecular Speciation, and Geometric Curvature: Controlling Electrochemical Selectivity and Where the Molecule Goes
Abstract: The grand challenges related to the global climate crisis and sustainable energy sources demand new design strategies to perform selective small molecule transformations and explore novel chemical phenomena, thereby creating additional dimensions in the materials design space. Toward this end, I will discuss: A) strategies to suppress the electrocatalytic hydrogen evolution reaction (HER) and boost the selectivity of CO2 reduction reaction (CO2RR) and N2 reduction reaction (N2RR), and B) the prediction of geometry-driven mechanochemical molecular motion on 2D materials, which opens new directions for controlling surface chemistry.
For part A,[1-4] I will highlight design strategies aimed at solving the challenge of HER vs. selective small molecule electroreduction, drawing lessons from distinct systems, including heterogeneous electrochemistry via nickel phosphides and homogeneous tandem electrocatalytic systems consisting of a redox mediator and molecular cocatalyst. In heterogeneous electrochemistry, we demonstrate how surface reconstructions can be leveraged under electrocatalytic conditions to achieve selective HER and CO2RR. In homogeneous electrochemistry, I will showcase how different speciation of a base-appended cobaltocene mediator can control HER vs. N2RR chemistry.
For part B,[5-7] I will describe how geometric effects, specifically curvature, can be exploited to achieve directional molecular motion of adsorbates on two-dimensional materials. This concept can be generalized to various types of curvature, including 1D and 2D curvature, for both one-legged and two-legged molecular walkers. By envisioning these molecular walkers as carriers of charge and disruptors of local bonding, our findings offer a novel approach to tuning the electronic structure of 2D materials for applications spanning from optoelectronics to catalysis.
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