Titania‐Supported Cu‐Single‐Atom Catalyst for Electrochemical Reduction of Acetylene to Ethylene at Low‐Concentrations with Suppressed Hydrogen Evolution

Abstract

Electrochemical acetylene reduction (EAR) is a promising strategy for removing acetylene from ethylene‐rich gas streams. However, suppressing the undesirable hydrogen evolution is vital for practical applications in acetylene‐insufficient conditions. Herein, we immobilized Cu single atoms on anatase TiO2 nanoplates (Cu‐SA/TiO2) for electrochemical acetylene reduction, achieving an ethylene selectivity of ∼97% with a 5 vol.% acetylene gas feed (Ar balance). At the optimal Cu single atom loading, Cu‐SA/TiO2 was able to effectively suppress HER and ethylene over‐hydrogenation even when using dilute acetylene (0.5 vol.%) or ethylene‐rich gas feeds, delivering a 99.8% acetylene conversion, providing a turnover frequency of 8.9 × 10−2 s−1, which is superior to other EAR catalysts reported to date. Theoretical calculations showed that the Cu single atoms and the TiO2 support acted cooperatively to promote charge transfer to adsorbed acetylene molecules, whilst also inhibiting hydrogen generation in alkali environments, thus allowing selective ethylene production with negligible hydrogen evolution at low acetylene concentrations.This article is protected by copyright. All rights reserved

Hydrogen Spillover Accelerates Electrocatalytic Semi-hydrogenation of Acetylene in Membrane Electrode Assembly Reactor

“…First, the further increase of the current density while maintaining C 2 H 4 selectivity above 85% is necessary to enhance the economic viability and maximize the potential of this technology. Second, most of the reported data are derived from three-electrode measurement systems, which differ from real reactor devices. , Real devices typically employ zero-gap membrane electrode assemblies (MEAs) with polymer electrolytes, offering reduced cell voltage and improved energy efficiency. , In contrast, the three-electrode systems utilize a liquid electrolyte layer with a thickness on the order of centimeters between the electrode and membrane . Moreover, the interface reaction environment, including local pH and interfacial cation concentration, may vary between high-concentration alkaline KOH solutions used in three-electrode studies and polymer electrolyte systems. , These differences can impact EASH performance, and the results observed under three-electrode conditions may not fully reflect the behavior in real devices.…”

“…Second, most of the reported data are derived from three-electrode measurement systems, which differ from real reactor devices. 19,20 Real devices typically employ zero-gap membrane electrode assemblies (MEAs) with polymer electrolytes, offering reduced cell voltage and improved energy efficiency. 21,22 In contrast, the three-electrode systems utilize a liquid electrolyte layer with a thickness on the order of centimeters between the electrode and membrane.…”

Lattice Strain and Mott–Schottky Effect of the Charge-Asymmetry Pd1Fe Single-Atom Alloy Catalyst for Semi-Hydrogenation of Alkynes with High Efficiency

“…Selective hydrogenation of alkynes is a crucial reaction in academia and the modern chemical industry, − where Pd-based catalysts are considered the most efficient. However, their applications are limited due to the excessive hydrogenation caused by their high activity. ,, Therefore, strategies involving poisoning the active sites have been developed to improve the catalytic selectivity of Pd-based catalysts. − One example is the commercial Lindlar catalyst, which is prepared by poisoning the loaded Pd catalyst with quinoline and Pb salts .…”

Cu–Pd bimetal-decorated siloxene nanosheets for semi-hydrogenation of acetylene

“…15–17 This strategy is exemplified by replacing some or most of the precious Pd with the cheap and abundant copper (Cu, 3d-transition metal) to shift down the d-band of Pd and disperse its active sites, leading to weakened adsorption of ethylene to avoid over-hydrogenation. 18–22 Despite the efficacy of this strategy, previous efforts have predominantly been focused on only the metals, while there have been few explorations of functional support materials beyond the traditional ones like SiO 2 and Al 2 O 3 .…”