"Polyoxometalate-Based Au–Ag Alloy Nanocatalysts for Efficient Electrochemical CO2 Reduction Reaction"
K. Kawakami, K. Yonesato, S. Kikkawa, S. Yamazoe, T. Kaneko, T. Uruga, F. Amano, Y. Honjo, T. Hatsui, K. Yamaguchi, K. Suzuki
ChemCatChem, 18, e01423.
The electrochemical CO2 reduction reaction (CO2RR) to carbon monoxide (CO) offers a promising strategy for mitigating global warming while providing a valuable industrial feedstock. Polyoxometalates (POMs), anionic metal–oxo clusters, are attractive precursors for CO2RR catalysts owing to their structural and compositional tunability, as well as their versatility of their countercations. However, POM-based CO2RR catalysts often exhibit limited activity and require high overpotentials. Herein, we report a high performance CO2RR nanocatalyst derived from a Ba2+ salt of an Au–Ag alloy nanocluster incorporated in a POM framework, [Au8Ag26(P8W48O184)]24− (AuAg), supported on a carbon black (Ba-AuAg/C). This system achieves a high current density (171 ± 4 mA cm−2) and Faradaic efficiency (95.3 ± 4.2%) for CO production at a low overpotential (−0.39 VRHE), outperforming previously reported POM-based CO2RR catalysts. Postreaction analyses reveal the transformation of Ba-AuAg/C into small Au–Ag alloy nanoparticles with uniform elemental distribution, along with WOx nanoaggregates. Control experiments and detailed characterizations highlight the critical roles of the constituent elements, countercations, and catalyst structure in achieving superior catalytic performance. This work provides a new design strategy for the development of highly efficient and selective POM-based nanocatalysts for electrochemical CO2 conversion.