CO₂‐to‐HCOOH Electrochemical Conversion on Nanostructured Cu_xPd_100−x/Carbon Catalysts

Abstract

Selective electrochemical conversion of CO 2 to HCOOH is obtained at the surface of a carbon-supported bimetallic cathode material composed of copper and palladium nanoparticles. Polycrystalline copper or large copper particles are well-known to catalyze CO 2 reduction to hydrocarbons at relatively negative potentials, or when their surface is covered by copper oxides (Cu 2 O and CuO). Cu-based materials modified by various palladium contents (0 < × < 100), were synthesized by using the microwave-assisted polyol method to serve as a cathode in the selective CO 2 -into-HCOOH transformation. Here-in, we developed a targeted preparation route toward the metal content/catalytic activity relationship correlating atomic ratio with faradaic efficiency (FE) to formate formation (ca. 60 % FE) at À 0.72 V vs. RHE, which represents a 703 mV overpotential at pH = 7. Consequently, the occurrence of this reduction reaction slows down the parallel H 2 production from the solvent consumption, while the neighboring CuÀ Pd provides excellent activity and a good efficiency toward CO 2 reduction via the hydridation of the CO 2 molecule to orientate the reaction to formate rather than carbon monoxide or H 2 evolution.

CO2 or Carbonates – What is the Active Species in Electrochemical CO2 Reduction over Fe‐Porphyrin?

“…This assessment agrees also well with evidence from X-ray absorption spectroscopy for Fe single atom catalysts. [58] Assuming a pH of 7 which is commonly used for CO 2 RR in water, [55][56][57][59][60][61] the Fe(I)(ppy) complex may react either with CO 2 , HCO 3…”

“…Assuming a pH of 7 which is commonly used for CO 2 RR in water, [55–57,59–61] the Fe(I)(ppy) complex may react either with CO 2 , HCO 3 − or H 2 CO 3 . CO 3 2− on the other hand is only present in very minor amounts under these conditions but has nevertheless been included in this study for the sake of completeness.…”

Recent advances in nanoscale engineering of Pd-based electrocatalysts for selective CO2 electroreduction to formic acid/formate

“…In electrocatalytic CO 2 reduction reaction (CO 2 RR) systems, renewable electricity powered electrocatalysis could convert CO 2 into several C 1 -C 3 products, including formic acid (HCOOH)/formate (HCOO -) [16,17] , carbon oxide (CO) [18] , methane (CH 4 ) [19] , ethanol (CH 3 CH 2 OH) [20] , ethylene (C 2 H 4 ) [21] , acetic acid (CH 3 COOH) [22,23] , n-propanol (CH 3 CH 2 CH 2 OH) [24] , etc. Of these reaction products, formic acid, in particular, is a highly valuable liquid product and an important platform chemical in a variety of industries, such as pharmaceuticals, metallurgical, and leather industries.…”

“…It is crucial to design sophisticated catalysts with superior catalytic performance given the ongoing development of ECO 2 RR and the rising demand for formic acid/formate products. Main-group p-block metals, such as indium (In) [30] , tin (Sn) [31] , and bismuth (Bi) [16] , have been reported to exhibit exclusive selectivity toward formic acid/formate [25,32] . Even though enormous progress has been made in achieving high Faraday efficiency (FE), it is still challenging to produce formic acid/formate with a high overall energy efficiency because the reactions have sluggish kinetics and high overpotentials on main-group p-block metals.…”