Abstract
Particle-based electrocatalysts need to be glued on an electrode, where fast and slow steps of the reaction are spatially and temporally convoluted near the particles. Since the particles are under continuous electrochemical stress, decay in their catalytic performance (a.k.a., fatigue) often occurs due to degradation of the active materials, detachment of particles and deteriorating kinetics. Here we report that these problems are well addressed by fluidizing the particles. The catalysts, instead of being fixed on an electrode, are now fluidized in the electrolyte. Reaction occurs when individual particles collide with the electrode, which collectively delivers a continuous, scalable and stable electrochemical current. Since the catalysts now work in rotation, they experience much faster kinetics and avoid the buildup of excessive electrochemical stress, leading to orders of magnitude higher particle-average efficiency and greatly enhanced fatigue resistance. Proof-ofconcepts are demonstrated using Pt/C catalysts for three well-known reactions, including oxygen evolution, hydrogen evolution and methanol oxidation reactions, all of which suffer severe performance decay using Pt/C under different mechanisms. Fluidized electrocatalysis breaks the spatial and temporal continuum of electrocatalytic reactions, and makes them drastically more fatigue resistant. It is material- and reaction-agnostic, and should be a general approach to enhance electrocatalytic reactions.
Original language | English (US) |
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Pages (from-to) | 31-41 |
Number of pages | 11 |
Journal | CCS Chemistry |
Volume | 2 |
Issue number | 1 |
DOIs | |
State | Published - Feb 2020 |
Funding
Y.Z. and Y.K. thanks University of Electronic Science and Technology of China (UESTC) for supporting their academic visit and research activities at Northwestern that generated most data reported in this work. Y.Z. also thanks her new faculty startup fund at Hunan University, which supported her to reproduce the work and generate some new data during the review of the manuscript. J.H. thanks the support from the Robert R. McCormick School of Engineering and Applied Science at Northwestern, and the Humboldt Research Award, an earlier Guggenheim Fellowship and an earlier gift fund from the Sony Corporation, which offered the intellectual freedom for him to indulge in new and unfunded research ideas during his academic leaves and conceptualize this work. This work made use of the TEM facility of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. The authors thank Luke Prestowitz, Alane Lim, Kevin Chiou, Prof. Markus Antonietti from Max Planck Institute of Colloids and Interfaces for helpful discussions. We also thank the anonymous reviewers for their helpful comments and suggestions.
Keywords
- Electrocatalyst stability
- Fatigue-resistance
- Fluidized electrocatalysis
- Reaction time scale
- Single particle reactions
- Transient current
ASJC Scopus subject areas
- General Chemistry