Comparative Study of Carbon Supported Pb, Bi and Sn Catalysts for Electroreduction of Carbon Dioxide in Alkaline Medium

Abstract

A gas diffusion electrode type arrangement was employed to evaluate carbon supported Pb, Bi and Sn nanopowders as electrocatalysts for electrochemical reduction of carbon dioxide in alkaline media (0.5 M NaHCO 3 ). The structural analysis, shape and topographical characterization, and the surface composition analysis of the catalysts were performed by XRD, SEM, TEM and XPS, respectively. The electrochemical techniques used were cyclic voltammetry, linear sweep voltammetry and chronoamperometry. Cyclic voltammetry was used to study the basic redox properties of the surface, while linear sweep was used to measure the response in argon and carbon dioxide saturated solutions. Chronoamperometry was carried out at four potentials to compare the products and their rate of formation for all the catalysts at ambient temperature and pressure. The formate production rate was observed to be highest for lead among the three catalysts evaluated. The value obtained was 0.576 mmol/h at −1.94 V vs RHE with a Faradaic efficiency of ∼ 30%. Further, the activity was found to be stable during the electrolysis and the current density was almost ∼35 mA/cm 2 geo . Based on the experiments conducted in this study, a comparative result of activity towards CO 2 electroreduction to formate was concluded as Pb > Bi > Sn.

Facile Synthesis of Nanostructural High‐Performance Cu–Pb Electrocatalysts for CO2 Reduction

“…The oxidation peaks of Cu [Cu→Cu(I)→Cu(II)] and the reduction peak of PbO [PbO→Pb] on Pb ar /Cu NWs confirm the presence of Cu and Pb elements on the surface. The reduction peak of PbO to Pb has been previously observed on Pb/C electrode (around 0.1 V vs RHE) and Pb foil electrode (around 0 V vs RHE) in similar electrolyte systems. Clearly, the current density of Pb ar /Cu NWs was much lower than that of Cu NWs, indicating that Pb significantly suppressed the H 2 evolution reaction (HER).…”

“…As for the elemental speciation, both zero‐valent metals (Cu, Pb, and Ni) and their oxides are identified and the metal oxides are the results of re‐oxidation by air during the storage and characterization . In particular, Pb is prone to oxidation in air to form freshly native oxide (Pb Ntv Ox) and Kumawat and Sarkar have proved that the Pb peak at 138.5 eV was PbO formed during the manipulation of the characterization.…”

“…Of transition metals, Cu and post‐transition metals (Pb, Sn, In, Bi) are promising materials, primarily because of Cu's low cost, high abundance, and catalytic activity and the post‐transition metals' high overpotentials of H 2 evolution . Among these four post‐transition metals, Pb exhibits high H 2 overpotential and excellent selectivity to HCOOH, a key and basic chemical in widespread applications . However, pristine polycrystalline Cu catalyst suffers instability and poor selectivity toward reduction products, including carbon monoxide, formic acid, hydrocarbon fuels (e.g., methane), and alcohols (e.g., methanol), while low total current density (ranging from −0.6 to −5.5 mA cm −2 ) at the potential lower than −1.2 V versus reversible hydrogen electrode (RHE) and inconsistent faradic efficiency (ranging from 5% to 90%) are the major disadvantages of Pb …”

Electrochemical reduction of CO2 on Pb–Bi–Sn metal mixtures: importance of eutectics

“…reduces CO 2 exclusively to formate ions in alkaline medium. Recently we have demonstrated the use of a gas diffusion layer electrode wherein the nanoparticles of Pb, Bi and Sn reduced CO 2 to produce formate ions in alkaline medium [1]. It was observed that nanoparticles of Pb outperformed Bi and Sn, both in terms of formation rates of formate ions and Faradaic efficiencies.…”

“…It may be reiterated here that all the three metals exhibit different crystal structures. An attempt was made by the authors of this work to synthesize metal alloy nanoparticles (Pb, Bi and Sn) by a method similar to that of preparing monolithic/mono metallic metal nanoparticles by sodium borohydride reduction mentioned elsewhere [1]. The supported catalyst particles were then heat treated under Argon atmosphere at temperatures of 200 and 400 °C in two independent experiments.…”