Electro‐Reconstruction‐Induced Strain Regulation and Synergism of Ag‐In‐S toward Highly Efficient CO₂ Electrolysis to Formate

Abstract

Formate production from direct CO2 electrolysis is economically appealing yet challenging in activity, selectivity, and stability. Herein, sulfur and silver dual‐decorated indium quasi‐core–shell structures with compressive or tensile strain are rationally designed for efficiently electrocatalyzing CO2 to formate. The introduction of Ag and S increases the current density, Faradaic efficiency, and operational stability of formate both in H‐cell and flow cell systems. As a result, the optimized Ag‐In‐S bimetallic catalysts exhibit the FEHCOO− of ≈94.0% with a JHCOO− of more than −560.0 mA cm−2 at ≈−0.951 VRHE in the flow cell system, which far surpasses the undecorated In catalyst. The experimental and theoretical calculations provide a deeper understanding of the role of the interfacial strain between In or In4Ag9 shell and AgIn2 core in boosting the electrocatalytic CO2 reduction efficiency, in which the formation energy of *OCHO intermediate decreases and the charge transfer rate is accelerated by interface strain.

Stabilizing Oxidation State of SnO2 for Highly Selective CO2 Electroreduction to Formate at Large Current Densities

“…In in situ ATR-IR spectra (Figure S22a,b), there are two typical peaks detected at 1630 and 1400 cm –1 for Cu–SnO 2 , while only one peak at 1630 cm –2 appears for pure SnO 2 even under high reduction potentials. We further used isotope D 2 O electrolyte to confirm that the 1630 cm –2 peak corresponds to H 2 O only for Cu–SnO 2 but associates with both H 2 O and CO 2 RR intermediate *COOH for SnO 2 (Figure a). − More importantly, the peak at 1400 cm –2 on Cu–SnO 2 can be assigned to the OCHO* species, which is the key intermediate for formate formation. ,, In addition, Bi substitution induces a similar adsorption effect to Cu–SnO 2 , and Pt substitution can adsorb little *OCHO only at high cathodic potentials and display an intermediate adsorption ability more like pure SnO 2 (Figures S22c,d and S23). In in situ Raman spectroscopy, the peak located at 630 cm –1 ascribed to A 1g modes of the Sn–O bond can be a response to the oxidation state of SnO 2 .…”

“…33−35 More importantly, the peak at 1400 cm −2 on Cu−SnO 2 can be assigned to the OCHO* species, which is the key intermediate for formate formation. 9,36,37 In addition, Bi substitution induces a similar adsorption effect to Cu−SnO 2 , and Pt substitution can adsorb little *OCHO only at high cathodic potentials and display an intermediate adsorption ability more like pure SnO 2 (Figures S22c,d and S23). In in situ Raman spectroscopy, the peak located at 630 cm −1 ascribed to A 1g modes of the Sn−O bond can be a response to the oxidation state of SnO 2 .…”

Doping and pretreatment optimized the adsorption of *OCHO on bismuth for the electrocatalytic reduction of CO2to formate

“…S4, † the HRTEM images of Cu/Bi 2 S 3 -0.59%, Cu/Bi 2 S 3 -1.24%, Cu/Bi 2 S 3 -2.67% and Cu/Bi 2 S 3 -3.49% show that the lattice spacings of 0.275 nm, 0.348 nm, 0.477 nm and 0.545 nm are smaller than those of the standard lattice spacings corresponding to (221), (310), ( 210) and (200) crystal planes, indicating that Cu is successfully incorporated into the lattice of Bi 2 S 3 and the lattice shrinkage is attributed to the small size of Cu compared with Bi. 32 In addition, the elemental mapping images show that Cu is uniformly distributed in Bi 2 S 3 . As shown in the high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image (Fig.…”

Lattice-strain and Lewis acid sites synergistically promoted nitrate electroreduction to ammonia over PdBP nanothorn arrays

“…39 Moreover, strain engineering of metal-based electrocatalysts is a powerful strategy to boost their electrocatalytic properties as the strain effect could lead to a shi in the d-band center and alter binding energies toward adsorbates. [40][41][42] As an example, Yu et al doped oxygen into a Ru unit cell to trigger tensile strains, which inhibited the HER by unblocking the hydrogen-hydrogen coupling but facilitated the formation of hydrogen radicals ($H). 31 The generated $H could promote the hydrogenation of reaction intermediates to produce ammonia.…”