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Published on: January 4, 2018
Ampere-Level Acetylene-to-Ethylene Electrosynthesis by a Spillover-Storage-Relaxation Hydrogenation Mechanism to
Fanpeng Chen1, Yichen He1, Bo-Hang Zhao1
1Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, China.
Abstract:
The scaling relationship between the activity and selectivity of electrocatalytic hydrogenation reactions (EHRs) is caused by severe hydrogen evolution reactions and overhydrogenation because of the inevitable blocking of active sites through excessive adsorbed hydrogen (*H) at high current density. Herein, a spillover-storage-relaxation hydrogenation mechanism is proposed to overcome the scaling relationship. By employing acetylene (C2H2) to ethylene (C2H4) conversion as an example, Cu-supported atomically dispersed WOx (WOx/Cu), with abundant interfacial *H-formation Cu and *H-reservoir WOx sites, is theoretically predicted and experimentally proven to be a promising catalyst. Consequently, WOx/Cu is synthesized and demonstrates a C2H4 partial current density of ∼1.43 A cm-2, with a C2H4 Faradaic efficiency higher than 95%. The *H transfer from Cu to WOx not only frees sites for C2H2 adsorption but also reserves a hydrogen source for subsequent hydrogenation. Additionally, such a mechanism is suitable for Mo(W)Ox/Cu(Ag) in other EHRs.
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