Current atomic-level understanding of electrochemical nucleation and growth on low-energy surfaces

Abstract

This review presents recent progress in the understanding of electrochemical phase formation on low-energy substrates, which is essential for metal electrodeposition and the design of stable batteries. Advanced characterization techniques and ultrasensitive electrochemical instrumentation give access to experimental data that were not available a few years back. Besides, the continuous development of theoretical models gradually provides a more complete description of multiple nucleation. However, important contradictions between experimental findings and theoretical formulations are found: nonclassical growth pathways, single-atom critical clusters, and cluster densities that are orders of magnitude higher than the calculated number of active sites. New descriptions of the initial steps of nucleation are discussed. They are grounded on nucleation being a nonactivated process, in which the initial stages of phase formation could involve simply adsorbed atoms collapsing into larger clusters driven by minimization of the overall interfacial energy. Finally, some remaining challenges and possible research directions are outlined.

Electrodeposition of nanostructured catalysts for electrochemical energy conversion: Current trends and innovative strategies

“…The focus is set on correlating innovative electrochemical growth strategies with the field of application and mechanistic understanding of the electrodeposition process. This paper complements our recent review of the latest advances in electrochemical nucleation and growth [8].…”

“…In general, we expect that electrodeposition will keep unravelling its potential as the preferred method for electrocatalyst synthesis, once a deeper understanding of the electrochemical growth process [8] is attained for complex chemistries and surfaces. This would allow 1) better controlling the morphology and the surface composition of complex bifunctional electrocatalysts, and 2) studying, in a systematic way, the interplay of kinetics and mass transport during electrocatalysis at nanostructured electrodes.…”

Scanning electrochemical cell microscopy for the study of (nano)particle electrochemistry: From the sub‐particle to ensemble level

“…Complementary high‐resolution STEM imaging revealed that a range of nanostructures from single Pt atoms (imaged directly on the CCTG support) to amorphous, monocrystalline, and polycrystalline PtNPs (and aggregates of these) coexist during the early stages of nucleation and growth, providing further support to the recently proposed electrochemical aggregative growth mechanism. [ 42 ]…”

Deciphering Competitive Routes for Nickel‐Based Nanoparticle Electrodeposition by an Operando Optical Monitoring

“…The electrodeposition of metal-based nanostructures is paramount in various applications (next-generation transistors, or preparation of active electrodes). [1,2] This is because the control of the electrode current or potential enables to predict the nature of the electrodeposits (composition, size, etc.). However, such prediction is more complex for earthabundant iron group elements whose electrochemical reduction competes with inhibiting reactions such as water reduction.…”

“…[12] To apprehend the contributions of such competing chemical pathways, a complementary in situ signature is needed. [2,[13][14][15][16][17] E.g. coupling electrochemistry to high resolution label-free optical microscopy [15][16][17] has proved to be effective to monitor metal deposition at single NPs with high temporal resolution and sensitivity, [18][19][20][21] as well as to differentiate metallic NPs from other nanoobjects (e.g.…”