The Necessity for Multiscale In Situ Characterization of Tailored Electrocatalyst Nanoparticle Stability

Abstract

Tailored nanoparticles have opened up several exciting avenues to boost the activity and selectivity of structure-sensitive electrocatalytic reactions, such as the electrochemical carbon dioxide (CO2) reduction (eCO2RR). Colloidal chemistry provides the perfect toolbox to synthesize electrocatalyst nanoparticles on demand with atomic precision, in order to control and steer the electrocatalytic reactions of interest to the desired products. Not only does colloidal chemistry offer a means to prepare nanoparticles with well-defined sizes and shapes, it also allows easy deposition on any desired substrate (e.g., porous substrates) due to the solution processability. But what you see after synthesis with ex situ characterization techniques is not always what you get during the electrocatalytic reaction. Like any other electrocatalyst material, colloidal nanoparticles are prone to restructuring, and hence, the reaction output is altered due to destabilization of the electrocatalyst. This destabilization of the electrocatalyst nanoparticles is currently one of the major bottlenecks for the widespread implementation of electrocatalysts in the chemical industry. This calls for the necessary development and application of in situ characterization techniques to probe the morphology and composition of the tailored electrocatalyst nanoparticles over multiple length scales, in order to rationally design the next generation of stable electrocatalyst nanoparticles. Through detailed spatiotemporal in situ characterization, we can take full advantage of the possibilities that colloidal chemistry offers for electrocatalyst preparation with superior activity, selectivity, and stability. In this perspective, the necessity for in situ characterization of electrocatalyst nanoparticle stability is highlighted. For this purpose, first the progress of colloidal nanoparticles for electrocatalytic conversion reactions is briefly discussed, after which the focus shifts toward in situ characterization of the (in)stability of the tailored nanoparticles during the reaction of interest, ideally under industrially relevant conditions. This perspective shows that in situ characterization of electrocatalyst deactivation requires a multiscale approach, and that without combined in situ characterization we will remain blind to several aspects that are known to influence electrocatalyst performance.

Operando methods: A new era of electrochemistry

“…For electrochemistry, operando methods are defined here as analytical techniques that provide a comparable driving force (applied potential) to achieve a comparable reaction rate (current density), relative to standard electrochemical cells [4]. This review will first introduce recent breakthroughs in developing multimodal operando/in situ methods [9,11], particularly operando electrochemical liquid-cell STEM (EC-STEM) and correlative synchrotron X-ray methods. Selected examples of representative STEM or TEM (S/TEM), hard and soft X-ray methods will be discussed in detail.…”

“…The overview of Table 1 delivers the important message that no single technique can possibly satisfy such an ideal requirement. Therefore, multimodal techniques are highly desirable to provide comprehensive information and approach a complete understanding of complex solidliquid interfaces [11]. Although aberration-corrected STEM imaging can routinely achieve sub-Å spatial resolution in vacuum, the imaging resolution of EC-STEM is often limited to a few nanometers by counting statistics, at a beam dose of 1-10 e -/Å 2 or lower to reliably study beamsensitive samples in liquid [12,[15][16][17].…”

“…and/or X-ray techniques, correlation of electrons and X-rays as structural probes with molecular probes (vibrational spectroscopy) [1,5,8], online product detection (DEMS) [9,66,67], online inductively coupled plasma (ICP) MS [68] and local activity (SECM) [10,69,70]. This combined approach will contribute to elucidating complex structural evolution under realistic electrochemical conditions, which otherwise will be impossible to comprehend with individual techniques [11,71]. (4) Synchronization of electrochemical measurements with EC-STEM or X-ray data acquisition with the development of integrated and automated data processing software.…”

Highlights from 2023 and Chemistry of Materials’ 35th Year

“…Like the analysis by Click and Rosenthal, Jonathan De Roo emphasized The Surface Chemistry of Colloidal Nanocrystals Capped by Organic Ligands , and Emily Tsui and her team discussed Redox Reactions at Colloidal Semiconductor Nanocrystal Surfaces . Moving toward applications, Ward van der Stam puts emphasis on The Necessity for Multiscale In Situ Characterization of Tailored Electrocatalyst Nanoparticle Stability . Additional Reviews or Perspectives make our list of recommended reading and include Differential Analysis of Galvanostatic Cycle Data from Li-Ion Batteries: Interpretative Insights and Graphical Heuristics , Advances in the Synthesis of Halide Perovskite Single Crystals for Optoelectronic Applications , Self-Driving Laboratory for Polymer Electronics , and Chemical Principles of Intrinsic Topological Superconductors .…”

Structure−Performance Relationships of Copper and Post−Transition Metals in Electrochemical CO2 Reduction

“…Figure 1.18 depicts multiscale characterization techniques for catalyst materials, including their respective ranges of lateral resolution and atomic detection limits. [125] Vibrational spectroscopies such as infrared (IR) and Raman, [126,127] microscopies including Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM), [128][129][130] and X−ray characterization techniques such as X−ray Absorption Spectroscopy (XAS), [131,132] X−ray Photoelectron Spectroscopy (XPS), [133,134] 1 and X−ray Diffraction (XRD) [135] have been utilized to investigate the morphology, composition, and surface chemical state of electrocatalysts. In addition, these techniques have been used to track the interaction between adsorbed intermediates and electrode−electrolyte interfaces.…”