Electrochemical interfacial influences on deoxygenation and hydrogenation reactions in CO reduction on a Cu(100) surface

Abstract

a Electroreduction of CO2 to hydrocarbons on copper surface has attracted much attention in the last decades for providing a sustainable way for energy store. During the CO2 and further CO electroreduction processes, the deoxygenation that is C-O bond dissociation, and hydrogenation that is C-H bond formation, are two main types of surface reactions catalyzed by copper electrode. In this work, by performing the state-of-the-art constrained ab initio molecular dynamics simulations, we have systematically investigated the deoxygenation and hydrogenation reactions involving two important intermediates, COHads and CHOads, under various conditions of (i) on Cu(100) surface without water molecules, (ii) at the water/Cu(100) interface and (iii) at the charged water/Cu(100) interface, in order to elucidate the electrochemical interfacial influences. It has been found that the electrochemical interface can facilitate considerably the C-O bond dissociation via changing the reaction mechanisms. However, the C-H bond formation has not been affected by the presence of water or electrical charge. Furthermore, the promotional roles of aqueous surrounding and negative electrode potential in the deoxygenation have been clarified, respectively. This fundamental study provides an atomic level insight into the significance of electrochemical interface towards electrocatalysis, which is of general importance in understanding electrochemistry.

An insight into methanol oxidation mechanisms on RuO2(100) under an aqueous environment by DFT calculations

“…From the simulations performed in an aqueous interfacial model with explicit water molecules, we may learn a great deal about electrocatalysis at the atomic scale than without them. [25][26][27][28][29][30][31][32][33] Some results have shown that the presence of aqueous solution has a great impact on mechanisms and energetics of surface reactions.…”

Tuning the Selective Ethanol Oxidation on Tensile‐Trained Pt(110) Surface by Ir Single Atoms

“…For example, in acidic media, the Pt(110) surface can effectively catalyze CC bond cleavage, while the Pt(111) surface is almost inert. [ 15–17 ] Apart from (110) surface, alloying or doping Pt with other suitable metals to form Pt‐based nanocatalysts is an actionable strategy to enhance C1 pathway selectivity for EOR. [ 18–21 ] Among various Pt‐based nanocatalysts for the EOR, Pt–Ir nanocatalysts or nanocatalysts with Pt–Ir surface have attracted attention due to their remarkable advantages in C1 pathway selectivity.…”

Potential-Dependent Competitive Electroreduction of CO2 into CO and Formate on Cu(111) from an Improved H Coverage-Dependent Electrochemical Model with Explicit Solvent Effect

“…Electrochemical reduction of CO 2 into useful and stable chemical fuels represents a promising approach and attracts significant attention to mitigate CO 2 emissions in the atmosphere by supplying renewable electricity that generated from hydropower, wind, and solar. − Among a series of metals that can electrochemically reduce CO 2 , − Cu electrodes have unique ability to electro-reduce CO 2 into hydrocarbons, such as CH 4 and C 2 H 4 . − Moreover, early experimental and theoretical investigations had reached consensus on the existence of a crucial intermediate CO adsorbed on the Cu surface during CO 2 electroreduction. ,− However, a high overpotential of ca. 1.0 V for a significant current density and low selectivity toward a particular species, such as CO, limited its application. − Because of unique electrocatalytic ability of Cu electrodes, it is usually used to determine and validate CO 2 electroreduction mechanisms to seek new Cu-based alloy electrocatalysts in a more efficient way that can lower overpotentials and improve the selectivity of CO against its competitors, formate (HCOO – ) species and H 2 . − Thus, CO 2 electroreduction mechanisms on the Cu surface have been extensively investigated by using experimental and theoretical methodologies. − …”

“…However, theoretically studying the electrocatalytic mechanisms occurring at the electrode/aqueous interfaces is a challenging task because the considerations of solvation and electrode potential are required. Previously, the vacuum/solid interfacial model or the fixed H 2 O molecules were usually employed for the investigations of CO 2 reduction mechanism on the Cu electrodes in many theoretical calculations to reduce computational cost, leading to be not very convincing results. , To more realistically simulate the electrode/aqueous interfaces, some theoretical methods have been proposed. − For example, ab initio molecular dynamics simulations (AIMD) may be able to describe the dynamic nature of H 2 O molecules and provide atomic insights into the mechanisms of CO 2 electroreduction into CO on Cu(100). − Using the AIMD simulations model and an aqueous interfacial model with explicit H 2 O molecules, electrical field effects from solvated proton–electron transfer have been showed to play an important role in C–O bond breaking and CO formation mechanism. , The electroreduction pathways to CO and HCOO – species on Cu(100) were also examined by Goddard et al using AIMD simulation with an explicit description of H 2 O molecules . They concluded that chemisorbed CO 2 δ− can be an intermediate in forming CO with the conversion from CO 2 δ− to physisorbate CO 2 as the rate-determining step, while HCOO – species formation proceeded via a different route with surface-adsorbed H reacting directly with the physisorbate CO 2 .…”