Accelerating Pd Electrocatalysis for CO₂-to-Formate Conversion across a Wide Potential Window by Optimized Incorporation of Cu

Abstract

Electrochemical reduction of carbon dioxide (CO 2 ) to formate is a viable way to reduce CO 2 emissions and realize a carbon-neutral energy cycle. Although Pd can convert CO 2 to formate with a high Faradaic efficiency at minimal overpotentials, it suffers from a limited and narrow potential window. Alloying is an important strategy for the catalyst design and tuning the electronic structures. Here, we report a series of PdCu bimetallic alloy catalysts with tunable compositions based on dendritic architectures. Optimal introduction of Cu atoms into the Pd matrix facilitates formate production and suppresses CO generation. In 0.1 M KHCO 3 aqueous solution, our best candidate, Pd 82 Cu 18 catalyst, delivered a high formate Faradaic efficiency of 96.0% at −0.3 V versus RHE. More interestingly, the high selectivity (>90%) toward formate maintained an enlarged electrochemical potential window of 600 mV. The ensemble effect with electronic coupling between Pd and Cu upon alloying and its induced moderate surface O-containing configuration were found to enhance the formate formation and suppress CO poisoning during CO 2 reduction.

Upgrading CO2 into acetate on Bi2O3@carbon felt integrated electrode via coupling electrocatalysis with microbial synthesis

“…Because of some limitations of low solubility, storage, and safety issues, H 2 does not qualify as a broad applicable alternative; however, such limitations do not exist in formate 25 . Moreover, formate is a selective product easily obtained from ECO 2 RR by electrocatalysis 26,27 . Thus, coupling electrocatalysis and microbial synthesis in one compartment to establish a hybrid bioinorganic system is an appealing way for CO 2 conversion, which possesses their respective advantages of both CO 2 fixation ways, including high efficiency and specificity toward acetate by microbial synthesis and high selectivity for formate by electrocatalysis 28–31 .…”

“…25 Moreover, formate is a selective product easily obtained from ECO 2 RR by electrocatalysis. 26,27 Thus, coupling electrocatalysis and microbial synthesis in one compartment to establish a hybrid bioinorganic system is an appealing way for CO 2 conversion, which possesses their respective advantages of both CO 2 fixation ways, including high efficiency and specificity toward acetate by microbial synthesis and high selectivity for formate by electrocatalysis. [28][29][30][31] The in situ generated formate via ECO 2 RR proceeding on the catalyst surface provides reducing equivalent to attached microorganisms for subsequent biotransform of CO 2 to acetate.…”

Heterogeneous Structure of Sn/SnO2 Constructed via Phase Engineering for Efficient and Stable CO2 Reduction

“…Formic acid or formate is regarded as a suitable target product with high economic viability and widely applied in the realms of both industries and agriculture. , Previous studies demonstrate that the most appealing catalysts for formate production are represented by main group metals and their compounds, ,− possibly due to their non-close-packed crystal structures . In particular, Sn-based materials have attracted substantial interest since 1980s due to their low toxicity and earth-abundant features. − However, the sporadic Faraday efficiencies (ranging from 10 to 90%) and undesirable intrinsic activity still hinder their application, whereas the uncontrollable evolution of Sn species during the CO 2 RR process is proposed as the primary issue. ,− Generally, metallic Sn is prone to oxidation in air, and the oxide shell contributes to catalytic activity. , Nevertheless, the oxide shell tends to be reduced since the operating potential for the CO 2 RR is more negative than its standard redox potentials.…”

Composition sensitive selectivity and activity of electrochemical carbon dioxide reduction on Pd–Cu solid-solution alloy nanoparticles

“…34 Recently, Pd-based catalysts have attracted attention as highly active and selective catalysts for converting CO 2 to formate and CO in neutral electrolytes. [35][36][37][38] Although pure Pd generates CO and formate as CO 2 RR products, the competing hydrogen evolution reaction (HER) hinders the selectivity for the CO 2 RR products. 39 Alloying of Pd with Cu can suppress the HER activity and simultaneously improve the selectivity for the CO 2 RR products.…”