Probing Temperature Effect on Enhanced Electrochemical CO2 Reduction of Hydrophobic Au25(SR)18 Nanoclusters

The widely studied electrocatalytic CO2 reduction reaction (eCO2RR) has typically been operated at room temperature. However, practical electrolyzers might operate at elevated temperatures, but a major concern is low CO2 solubility. One promising strategy is to construct a hydrophobic interface to enhance CO2 diffusion. Regarding this, atomically precise gold nanoclusters (NCs) can be accurately decorated with hydrophobic ligands to create a local hydrophobic microenvironment to ensure rapid CO2 transfer, yet the temperature effect on the reaction kinetics remains unknown. Here, we report, for the first time, the temperature-dependent eCO2RR performance of hydrophobic Au25(SR)18 NCs by a close interplay between theory and experiment. Simulations revealed that the hydrophobic surface is very conducive to CO2 activation, and the proton transfer process for *COOH and *CO formation can be significantly affected by temperature via modulating interface hydrogen bonding. Particularly, an elevated temperature at 330 K dramatically increases the catalytic activity while simultaneously suppressing the competitive hydrogen evolution reaction. We experimentally demonstrate that Au25 exhibits high eCO2RR performance at 330 K, achieving a high CO Faradaic efficiency of ∼93% and a CO partial current density about 2 times higher than that at room temperature. This work opens exciting opportunities in developing efficient electrocatalysts via synergistic implementation of surface hydrophobicity and temperature-mediated interface engineering.