Noncovalent interactions on the electrocatalytic oxidation of ethanol on a Pt/C electrocatalyst

Abstract

Due to their environmentally friendly nature and high energy density, direct ethanol fuel cells have attracted extensive research attention in recent decades. However, the actual Faraday efficiency of the ethanol oxidation reaction (EOR) is much lower than its theoretical value and the reaction kinetics of the EOR is sluggish due to insufficient active sites on the electrocatalyst surface. Pt/C is recognized as one of the most promising electrocatalysts for the EOR. Thus, the microscopic interfacial reaction mechanisms of the EOR on Pt/C were systematically studied in this work. In metal hydroxide solutions, hydrated alkali cations were found to bind with OHad through noncovalent interactions to form clusters and occupy the active sites on the Pt/C electrocatalyst surface, thus resulting in low Faraday efficiency and sluggish kinetics of the EOR. To reduce the negative effect of the noncovalent interactions on the EOR, a shield was made on the electrocatalyst surface using 4‐trifluoromethylphenyl, resulting in twice the EOR catalytic reactivity of Pt/C.

Enhanced surface reconstruction of V-doped Ni3N driven by strong OH adsorption to boost 5-hydroxymethylfurfural electrooxidation for energy-saving H2 production

“…11 Therefore, enormous efforts have been made to develop more thermodynamically favorable organic oxidation reactions for replacing the OER. [12][13][14] In recent years, a wide range of organic oxidation reactions, including the oxidation of alcohols, 15 ammonia, 16 urea, 17 hydrazine 18 and biomass-derived compounds 19,20 have been explored to establish hybrid electrochemical water splitting. Particularly, the study on electrocatalytic oxidation of biomass derivatives has attracted extensive attention.…”

Mechanistic Investigations of Electrochemical Ethanol Oxidation Reaction by In Situ Raman Spectroscopy

“…The Electrochemical Ethanol Oxidation Reaction (EOR) constitutes the anodic reaction for a myriad of renewable energy conversion devices, [1] including Direct Ethanol Fuel Cells (DEFCs), [2] hybrid ethanol electrolysis, [3] and zinc‐ethanol‐air batteries [4] . Throughout the EOR process, ethanol initially adsorbs onto the catalyst surface, evolving into several adsorbed intermediates before final desorption [5,6] . To date, over 40 possible intermediates have been identified, [7] suggesting varied reaction pathways and correspondingly diverse catalytic performances across different catalysts.…”

“…[4] Throughout the EOR process, ethanol initially adsorbs onto the catalyst surface, evolving into several adsorbed intermediates before final desorption. [5,6] To date, over 40 possible intermediates have been identified, [7] suggesting varied reaction pathways and correspondingly diverse catalytic performances across different catalysts. Therefore, the accurate detection of reaction intermediates is crucial for elucidating the reaction mechanism, thereby improving selectivity and reducing the reaction barrier.…”

Alkali Metal Cation–Sulfate Anion Ion Pairs Promoted the Cleavage of C–C Bond During Ethanol Electrooxidation

“…Metal cations in the electrolytes have significant effects on reaction pathways of CO 2 reduction, oxygen reduction reaction, and hydrogen evolution reaction in addition to the role in conducting ions. − For example, metal cations facilitated the C–C bond formation in the CO 2 reduction on Cu electrodes . The cation and anion effects on the electrooxidation of ethanol were observed in alkaline and acidic electrolytes, respectively, − while the alkali metal (AM) cation effect in an acidic electrolyte has not been well investigated yet.…”

“…For the methanol oxidation, the catalytic performance correlated monotonically to the the hydration energy of the alkali metals, which affected the water activation through formation of OH ad –M + (H 2 O) x clusters at the interface . The theory has been used to explain the cation effect in other electrooxidation systems in the alkaline media. ,, However, few studies of the cation effect were reported in acidic media because of the complex interaction among cations, anions, and hydrated water molecules. Here, it is found that the cations affected the formation of AM + sulfate ion pairs evidenced by the in situ Raman spectroscopy.…”