%0 Journal Article
%A Bhowmik, Arghya
%A Hansen, Heine Anton
%A Vegge, Tejs
%D 2017
%T Electrochemical Reduction of CO2 on IrxRu(1–x)O2(110) Surfaces
%U https://acs.figshare.com/articles/journal_contribution/Electrochemical_Reduction_of_CO_sub_2_sub_on_Ir_sub_i_x_i_sub_Ru_sub_1_i_x_i_sub_O_sub_2_sub_110_Surfaces/5601553
%R 10.1021/acscatal.7b02914.s001
%2 https://ndownloader.figshare.com/files/9746428
%K RuO 2
%K O 2 exhibits
%K OCHO
%K adsorbate binding
%K Ir atom
%K OH
%K RuO 2 surface
%K alternative reaction mechanism
%K RHE
%K CO 2
%K CO 2RR onset
%K faradic efficiencies plague metal catalysts
%K adsorbate binding energies
%K ligand effects
%K t 2 g orbitals
%K methanol
%K CO 2RR volcano
%X High
overpotentials and low faradic efficiencies plague metal catalysts
for direct conversion of CO2 to methanol and other liquid
fuels. RuO2-based electrocatalysts have been observed to
evolve methanol at low overpotentials, which has been attributed to
an alternative reaction mechanism with oxygen-coordinated intermediates
that can circumvent the limitations imposed by the scaling relations
on metal catalysts. Here, we introduce an innovative concept of ligand
effects in oxide catalysts. Both IrO2 and RuO2 binds OH* and other intermediates from the electrochemical reduction
of CO2 (CO2RR) strongly, but the stable and miscible system
IrxRu(1‑x)O2 exhibits anomalous weaker binding energy in the presence of CO*
spectators, because of Ru–Ir ligand effects. The weakened adsorbate
binding leads to a very low CO2RR onset potential (methanol evolution
at −0.2 V RHE). An Ir atom at the bridge site with Ru neighbors
binds intermediates such as OH* and OCHO* much weaker, because of
synergistic ligand effects and adsorbate–adsorbate interactions.
Consequently, a RuO2 surface doped with Ir move close to
the top of the predicted CO2RR volcano for oxides, which offers a
significant improvement over state-of-the-art electrocatalysts for
conversion of CO2 into methanol. Analysis of electronic
structure parameters with adsorbate binding energies indicates the
ligand effect depletes electrons from the Ir atom and shifts the t2g orbitals. The lack of electron donation from CO* spectators
to Ir at the active site cause favorable adsorbate binding.
%I ACS Publications