Harmonizing the Electronic Structures of the Adsorbate and Catalysts for Efficient CO₂ Reduction

Abstract

In CO₂ electroreduction, the critical bottleneck lies in the CO₂ activation which requires high overpotentials. CO₂ activation is related to both the electronic structures of catalysts and those of adsorbates, thus an ideal catalyst should match its electronic structures with those of the adsorbate. Here, we harmonized the electronic structures of the adsorbate and Mn-doped In₂S₃ nanosheets for efficient CO₂ reduction. The introduction of Mn dopants into In₂S₃ nanosheets enhanced both the Faradaic efficiency (FE) for carbonaceous products and current density (<i>j</i>). At -0.9 V vs RHE, Mn-doped In₂S₃ nanosheets exhibited a remarkable FE of 92% for carbonaceous product at a high <i>j</i> of 20.1 mA cm^-2. Mechanistic studies revealed that Mn doping enabled the harmonic overlaps between the <i>p</i> orbitals of O atoms and <i>d</i> orbitals of Mn atoms near the conduction band edge of Mn-doped In₂S₃ nanosheets during the activation of CO₂. Due to the unique electronic structures of the coadsorbed configurations, Mn-doped In₂S₃ nanosheets exhibited an energy barrier for CO₂ activation into HCOO* lower than that over pristine In₂S₃ nanosheets.