Hierarchical Bimetallic Electrocatalyst with Amorphous SnO Layer for Highly Efficient Electroreduction of CO₂

Abstract

Renewable electricity-driven reduction of CO 2 into value-added chemicals has been recognized as a promising sustainable energy conversion method to achieve carbon-neutrality. Although Sn-based catalysts show excellent selectivity towards CO and HCOOH in CO 2 reduction, the reaction activity, i. e. current density, remains quite low (< 100 mA cm À 2 ). Herein, a hierarchical bimetallic electrocatalyst consisting of Cu foamsupported bundle-like structure and thin amorphous SnO layer was fabricated for efficient electroreduction of CO 2 to C1 products (CO and HCOOH). The hierarchical structure ensured higher large electrochemically active surface area, while the thin amorphous SnO layer could efficiently adsorb CO 2 , and stabilize the *CO 2 À intermediate formed in the rate-determining step, thereby boosting the reaction activity of CO 2 reduction. As a result, an unprecedented partial current density of 128.6 mA cm À 2 was achieved for C1 products at À 1.4 V vs. RHE with a Faradaic efficiency of 79.2 % in an H-type cell. The strategy of integrating optimized structure with active site here may be beneficial to other related energy conversion systems.

Tuning the oxidation state of SnOx and mass transport to enhance catholyte-free CO2-to-formate electrolysis

“…We note that SnO x layers are known to be robust against full reduction under CO 2 electrolysis conditions. 7,32,33 Thus, the XPS spectra in Fig. 3 indicate lasting differences in the characteristic surface chemistry and electronic structure of the catalysts prepared with SnO and SnO 2 -rich surfaces.…”

Sn-based electrocatalysts for electrochemical CO2 reduction

“…The observed improvements in electrocatalytic performance provided valuable insights into the significance of oxide-derived nanostructures in enhancing catalytic activity for CO 2 conversion. 111 Inspired by this, Huo et al 112 synthesized Cu bundle@SnO composite catalyst with high rough surface via deposition method, as depicted in Fig. 5a.…”