Modulating Activity through Defect Engineering of Tin Oxides for Electrochemical CO₂ Reduction

Abstract

The large‐scale application of electrochemical reduction of CO2, as a viable strategy to mitigate the effects of anthropogenic climate change, is hindered by the lack of active and cost‐effective electrocatalysts that can be generated in bulk. To this end, SnO2 nanoparticles that are prepared using the industrially adopted flame spray pyrolysis (FSP) technique as active catalysts are reported for the conversion of CO2 to formate (HCOO−), exhibiting a FEHCOO− of 85% with a current density of −23.7 mA cm−2 at an applied potential of −1.1 V versus reversible hydrogen electrode. Through tuning of the flame synthesis conditions, the amount of oxygen hole center (OHC; SnO●) is synthetically manipulated, which plays a vital role in CO2 activation and thereby governing the high activity displayed by the FSP‐SnO2 catalysts for formate production. The controlled generation of defects through a simple, scalable fabrication technique presents an ideal approach for rationally designing active CO2 reduction reactions catalysts.

Nanostructured β‐Bi2O3 Fractals on Carbon Fibers for Highly Selective CO2 Electroreduction to Formate

“…[37,54] We confirmed that these fractal morphology is retained after long-term CO 2 electrolysis under negative bias, as observed by SEM analysis of the post-reacted f-Bi 2 O 3 ( Figure S10). The XPS analysis of the post-reacted f-Bi 2 O 3 ( Figure S11) reveals the presence of -phase Bi 2 O 3 alongside metallic Bi, which is in line with the literature, [55] where negative potentials applied during CO 2 RR leads to the formation of metastable oxide species/interfaces that play a role in the CO 2 RR pathway. Interestingly, the TEM imaging of the post-reacted f-Bi 2 O 3 indicates that the surface of these f-Bi 2 O 3 are reduced to metallic Bi while the core remains oxidized (Figure S11).…”

A Disquisition on the Active Sites of Heterogeneous Catalysts for Electrochemical Reduction of CO2 to Value‐Added Chemicals and Fuel

“…We also carried out a thorough mechanistic investigation into the oxygen vacancy defects by synthetically manipulating the amount of defects in flame‐sprayed SnO 2 catalyst. Our results indicate a strong correlation with catalytic activity and the amount of oxygen hole centers, highlighting the importance of defect engineering for CO 2 RR in traditional catalysts …”

“…Data from refs. . The detailed catalytic activity of these catalysts is presented in Table S3 (Supporting Information).…”

Engineering Sn‐based Catalytic Materials for Efficient Electrochemical CO2 Reduction to Formate

“…prepared SnO 2 nanoparticles using flame spray pyrolysis and manipulated the concentration of oxygen hole centres and surface area by tuning the precursor feed rate due to incomplete combustion (Figure 5). [76] These oxygen hole centres arise from the cleavage of the Sn−O−Sn or the Sn−OH links, which results in additional electrons that could be trapped in the vacancies or donated to adjacent metal sites. This results in an electron‐rich catalyst surface which promotes CO 2 adsorption and lowers activation energy for the subsequent CO 2 reduction.…”