Photo/electrochemical Carbon Dioxide Conversion into C₃₊ Hydrocarbons: Reactivity and Selectivity

Abstract

Producing high‐value fuels and chemicals via photo/electrochemical CO2 reduction reaction (CO2RR) remains an attractive goal to mitigate the negative impact of CO2 emissions and provide a sustainable energy source. The large industrial scale is currently discriminated by the relatively low product selectivity (a high cost is expected for separating the products) and the activity. The selective CO2 reduction into higher‐order multi‐carbon products is desirable from the economic point of view. Yet, most of the reported electrocatalysts have produced C1 and C2 products; however, the production of C3 products is less common. Cu‐based catalysts are the most documented systems to produce C3 products because of the exclusive C−C coupling ability of the Cu system. However, creating multi‐carbon products on non‐Cu catalysts is unfairly discussed. Growing the research activity on non‐Cu catalysts will enrich the categories of alternative catalysts and propose more understanding of the CO2RR mechanism. This should guide the development of more creative catalysts with the optimum configuration for high activity and selectivity for high‐value C3 products. The catalysts′ development progress, including metallic Cu, biphase, or bimetallic Cu, non‐Cu‐based catalysts, has been discussed in light of the catalyst activity and selectivity. Some insights on the reaction mechanism for the desired C3 product (most commonly, n‐propanol) and other C3+ products are also discussed.

Alloy Catalysts for Electrocatalytic CO2 Reduction

“…[ 13,14 ] However, ECRR tends to develop C 2 and C 3 high‐value products and harsh reaction conditions. [ 15 ] The uniform surface with a homoatomic center is difficult to provide a high‐energy catalytic center for multi‐carbon products and keep good durability under acidic and alkaline conditions.…”

Enhancement in CO Selectivity by Modification of ZnO with CuxO for Electrochemical Reduction of CO2

“…Different products varying from C 1 , [ 11 ] C 2 to even C 3 [ 12,13 ] can be produced via electrochemical CO 2 RR. The activity and selectivity are affected by several parameters, including the nature of the electrocatalyst, applied potential, pH, type of electrolyte, etc.…”

“…Moreover, electrochemical CO 2 RR is performed using electrochemical principles where the only source of energy needed is electricity that can be harvested from renewable sources such as solar cells or wind turbines. [9,10] Different products varying from C 1 , [11] C 2 to even C 3 [12,13] can be produced via electrochemical CO 2 RR. The activity and selectivity are affected by several parameters, including the nature of the electrocatalyst, applied potential, pH, type of electrolyte, etc.…”

Electrochemical Reduction of CO2 using Solid Oxide Electrolysis Cells: Insights into Catalysis by Nonstoichiometric Mixed Metal Oxides

“…CO 2 is characterized by strong C–O bonds, making this compound very stable and inert, requiring a significant amount of energy for its activation . Processes to convert CO 2 into high-value products have been multifaceted, including thermal catalysis, and photo- and electro-catalysis. − Among these, electrocatalytic processes have shown promise, since product selectivities and yields from CO 2 can be tuned through adjusting the applied potential under mild reaction conditions, while circumventing the complexity of photocatalytic systems associated with direct coupling of photon and electron processes. Different types of electrochemical systems have been investigated for CO 2 electroreduction over the years. ,, This review mainly focuses on high-temperature electrochemical reduction using solid oxide electrolysis cells (SOECs) for converting CO 2 selectively to CO. CO is a valuable platform chemical with a wide range of industrial applications: for example, the synthesis of acetic acid by catalytic carbonylation of methanol and the production of formic acid by hydrolysis of methyl formate. − CO can also be coupled with H 2 and converted to liquid hydrocarbons using Fischer–Tropsch synthesis. , The electrochemistry at the solid/gas interface of the SOEC cathode is generally simpler than that of low-temperature electrochemical systems at solid/liquid interfaces .…”