Interface-sensitive Spectroscopy of Atomically-defined Solid/Liquid Interfaces Under Operating Conditions

Introduction

Charge-transfer reactions are key not only to the way that nature fuels life in photosynthesis but also in synthesizing sustainable fuels like hydrogen. Charge transfer occurs at interfaces with an applied potential, yet almost all our understanding of electrocatalytic activity trends comes from the bulk material properties in the as-prepared state.

Limitations in Current Understanding

We still lack interface-sensitive spectroscopy tools that can probe the composition and electronic structure under reaction conditions. Only with such interface-sensitive operando information can we fully understand the underlying reaction mechanisms and devise strategies for efficient energy conversion and storage.

Project Overview

In Interfaces at Work, I will overcome these limitations by developing novel interface-sensitive operando X-ray spectroscopies combined with model electrochemical surfaces with atomic-layer compositional control, merging the fields of surface science and liquid electrochemistry.

Objectives

My aim is to fully visualize the physico-chemical properties of the solid/liquid interface under operating conditions. Specifically, I will:

1. Develop a new laboratory-based, multicolour operando “meniscus XPS” (X-ray photoelectron spectroscopy).
2. Transform the recently invented “membrane XPS” by making it accessible to the relevant electrochemical materials using these materials themselves as new membranes.

Application of Techniques

I will apply these novel techniques to electrocatalyst and pseudocapacitor model systems based on epitaxial oxide thin films and 2D carbides.

Expected Outcomes

Ultimately, the proposed approach will allow me to track the surface and subsurface properties under applied potential to shed light on the electrochemical mechanisms. The operando insights will result in design rules for efficient energy conversion and storage based on the chemical and electronic properties of a true electrochemically active surface under operating conditions rather than the as-prepared bulk. This will help our transition towards sustainability.