Superscalar Phase Boundaries Derived Multiple Active Sites in SnO₂/Cu₆Sn₅/CuO for Tandem Electroreduction of CO₂ to Formic Acid

Abstract

The electrocatalytic CO2 reduction reaction (CO2RR) to fuels driven by electrocatalysts is a viable strategy for efficient utilization of emitted CO2. CO2RR involves multiple‐steps, including adsorption, activation, hydrogenation, etc. At present, copper‐tin alloy catalysts have shown the capability to reduce CO2 to formic acid or formate. However, their poor adsorption and activation capacities for CO2 molecules, as well as the sluggish kinetics in *H supply restrict the proton‐coupled electron transfer processes in the electrocatalytic CO2RR to produce formic acid. In order to solve the above problems, the ultra‐small SnO2/Cu6Sn5/CuO nanocatalysts with superscalar phase boundaries are fabricated by laser sputtering. The introduction of SnO2 enhances the adsorption and activation of CO2, while CuO promotes H2O decomposition and provides abundant *H intermediates, resulting in tandem catalytic sites on the SnO2/Cu6Sn5/CuO composite catalysts and thus leading to excellent CO2RR activity and high selectivity to formic acid. The Faradic efficiency of formic acid (FEHCOOH) at the SnO2/Cu6Sn5/CuO electrode reaches 90.13% along with a high current density of 25.2 mA cm−2 at −0.95 V versus reversible hydrogen electrode. The role of the multiphase boundaries constructed by introduction of oxides is confirmed by in situ infrared spectroscopy and kinetic isotope effects experiments, which is consistent with the design concept.

Laser-controlled tandem catalytic sites of CuNi alloys with ampere-level electrocatalytic nitrate-to-ammonia reduction activities for Zn–nitrate batteries

“…In this work, as a case study of regulated tandem site catalysts, Ni was successfully introduced into the Cu foil by a facile and fast laser irradiation method, which is conducive to the formation of alloys due to the characteristics of rapid heating and cooling during the preparation. 19,20 The obtained CuNi alloy nanoparticles on the Cu foil (CuNi NPs/CF) show the ampere-level NIRR performance with the highest NH 3 production rate of 94.57 mg h −1 cm −2 , the maximum faradaic efficiency (FE) of 97.03% and good stability for 12 h in an ultrahigh-concentration NO 3 − (44.3 g L −1 ) alkaline solution. The introduced Ni sites display great ability of O–H activation and strong capacity of H* supply, which is beneficial for the subsequent hydrogenation steps of NH 3 synthesis.…”

Cobalt Doping in MOF-Derived Carbon-Loaded Tin Nanomaterials for Enhanced Electrocatalytic CO2 Reduction

“…The results showed that the Co/Sn@C composite maintained a porous frame structure (Figure a), accompanied by crystals such as rhomboids, irregular cuboids, and hexagons, with sizes around 30–40 nm (Figure b). A high-resolution transmission electron microscopy (HRTEM) image of Co/Sn@C (Figure c) shows three distinct lattice spacings of 0.33, 0.27, and 0.16 nm, which are assigned to the (110) crystal plane of tetragonal SnO 2 , , the (002) crystal plane of tetragonal CoSn 2 , and the (002) crystal plane of tetragonal Sn, respectively. Further patterns of selected area electron diffraction (SAED) confirmed the above results.…”

Tin as a co-catalyst for electrocatalytic oxidation and reduction reactions

“…This tandem catalysis on Cu 6 Sn 5 /oxides provides an abundant supply of hydrogen species (*H) via proton transfer, resulting in enhanced CO 2 RR activity and selectivity. 141 2.4.1.2 Inhibition of the HER and improvement of CO selectivity by Sn doping. Sarfraz et al used Sn, an economical and abundant metal, in combination with oxide-derived copper (OD-Cu) to prepare highly selective catalysts.…”

“…This tandem catalysis on Cu 6 Sn 5 /oxides provides an abundant supply of hydrogen species (*H) via proton transfer, resulting in enhanced CO 2 RR activity and selectivity. 141…”