Opportunities and Challenges in CO₂ Reduction by Gold- and Silver-Based Electrocatalysts: From Bulk Metals to Nanoparticles and Atomically Precise Nanoclusters

Abstract

To tackle the excessive emission of greenhouse gas CO 2 , electrocatalytic reduction has been recognized as a promising way. Given the multielectron, multiproduct nature of the CO 2 reduction process, an ideal catalyst should be capable of converting CO 2 with high rates as well as high selectivity to either gas-phase (e.g., CO, CH 4 ) or liquid-phase products (e.g., HCOOH, CH 3 OH, etc.). Gold-and silver-based materials have been extensively investigated as CO 2 reduction catalysts for the formation of CO. This Perspective focuses on the advances of gold-and silver-based electrocatalysts for CO 2 reduction in terms of catalyst design as well as some insights from theoretical investigations. In particular, a special emphasis is placed on the newly emerging, atomically precise metal nanoclusters for CO 2 electroreduction. The strong quantum confinement effect and molecular purity as well as the crystallographically solved atomic structures of nanoclusters make this new class of catalysts quite promising in fundamental studies, and valuable mechanistic insights for CO 2 electroreduction at the atomic scale can be obtained. We hope that this Perspective highlights the opportunities and challenges in the exploration of emerging nanomaterials.

Electrolyte Effects on the Electrochemical Reduction of CO2

“…In general, CO production is dominant on transition metals such as Au, Ag and Zn, while formate production is dominant on p-block metals such as Sn, Pb and In. [8][9][10] In most cases, significant overpotentials are required to drive the electrochemical reduction of CO 2 and obtain products. For CO 2 reduction on copper surfaces the production of 16 different products has been reported, with low product selectivity.…”

Metal Nanoclusters: New Paradigm in Catalysis for Water Splitting, Solar and Chemical Energy Conversion

“…MNCs have a precise number of atoms providing maximum electrochemical accessibility of the core atoms during catalysis and are being considered as effective catalysts to address these problems. Despite their small size with low number of coordinating sites, they provide a high electronic density around the metal core atoms, which improves durability and selectivity, which facilitates the desorption of the poisoning species such as CO during catalysis …”

“…Despite their smalls ize with low number of coordinating sites, they provide ah igh electronic density around the metal core atoms, which improves durability and selectivity,w hich facilitates the desorption of the poisoning species such as CO during catalysis. [230] In addition to the NC size, their uniform dispersion and optimum interaction with the support (usually oxides) is also critical. Pd, Cu, andN ia re selective catalysts for CO 2 reduction.…”

Microwave‐Assisted Synthesis of Copper‐Based Electrocatalysts for Converting Carbon Dioxide to Tunable Syngas

“…[1] CO is highly desired in the industrial sector, since its mixture with hydrogen (H 2 ), namely synthetic gas or syngas, can be further converted to oxygenates and hydrocarbons through the Fischer-Tropsch process. [2][3][4] According to experimental and theoretical studies, gold (Au) and silver (Ag) are considered to be the best metal catalysts for converting CO 2 to CO. [5,6] Instead, copper (Cu) shows unique features of electrochemically converting CO 2 to a range of chemicals including alcohols and hydrocarbons, [7,8] while its selectivity for CO is low. However, by tuning the morphology and surface composition of the Cu-based catalysts, it is possible to adjust the selectivity for CO and to obtain syngas with various H 2 /CO ratios.…”