Electrocatalytic CO<sub>2</sub> Reduction with Atomically Precise Au<sub>13</sub> Nanoclusters: Effect of Ligand Shell on Catalytic Performance
Tetyana I. Levchenko, Hong Yi, Mark D. Aloisio, Ngoc Kim Dang, Guorui Gao, S. J. Sharma, Cao‐Thang Dinh, Cathleen M. Crudden
Abstract
High Resolution Image Download MS PowerPoint Slide Supported gold nanoclusters of the formula [Au 13 (L) 5 Cl 2 ] 3+ where L = N -heterocyclic carbene (NHC) or phosphine ligands are examined in the electrocatalytic CO 2 reduction reaction (eCO 2 RR) in a membrane electrode assembly cell configuration. Gold nanoclusters bearing bis NHC ligands are shown to exhibit improved catalytic performance compared with diphosphine-stabilized nanoclusters after activation at the optimum treatment temperatures. The thermal properties of the nanoclusters are shown to have a significant impact on their catalytic activity. Thermogravimetric analysis, UV–vis absorption spectroscopy, and X-ray photoelectron spectroscopy revealed that thermal treatment of [Au 13 (diphosphine) 5 Cl 2 ] 3+ nanoclusters results in complete loss of diphosphine ligands while [Au 13 ( bis NHC) 5 Cl 2 ] 3+ nanoclusters show stepwise and partial removal of bis NHC ligands. We propose that the partial removal of bis NHC ligands enables efficient activation of [Au 13 ( bis NHC) 5 Cl 2 ] 3+ clusters while conserving the core structure. This leads to the implication that intact clusters retaining at least some ligands in their coordination environment are more active than ligand-free clusters.