Ultra‐thin Pd and CuPd bimetallic alloy nanosheets for electrochemical reduction of CO2

Selective exposure of (111) crystal plane in Pd49Ag30Te4 by Tb doping to weaken Pd - C bond and promote electroreduction of CO2 to CO

Employing electric energy to convert carbon dioxide (CO2) into valuable small molecules is a potentially practical method in energy storage and greenhouse gas alleviation. A huge challenge for electrocatalytic CO2 reduction is to reduce overpotential to improve energy efficiency. Herein, we demonstrate that doping alloy Pd49Ag30Te4 (PAT) with rare-earth element Tb is beneficial for selective exposure of (111) crystal plane, which is a highly active crystal plane for producing carbon monoxide (CO). The as-prepared Tb2.9PAT exhibited high electrocatalytic performance with 95.7 % CO faradic efficiency at - 0.8 V (vs RHE), far exceeding that of PAT, and coupled with good durability. In situ spectral study and theoretical calculations disclose that the introduction of Tb regulates the d-band center of PAT alloy, weakens the Pd - C bonding ability, and promotes the desorption of *CO in the rate-determining step. This study provides a method for doping induced selective exposure of crystal face, which provides new idea for improving catalytic performance.

Alloying strategies for tuning product selectivity during electrochemical CO2 reduction over Cu

Excessive reliance on fossil fuels has led to the release and accumulation of large quantities of CO₂ into the atmosphere which has raised serious concerns related to environmental pollution and global warming. One way to mitigate this problem is to electrochemically recycle CO₂ to value-added chemicals or fuels using electricity from renewable energy sources. Cu is the only metallic electrocatalyst that has been shown to produce a wide range of industrially important chemicals at appreciable rates. However, low product selectivity is a fundamental issue limiting commercial applications of electrochemical CO₂ reduction over Cu catalysts. Combining copper with other metals that actively contribute to the electrochemical CO₂ reduction reaction process can selectively facilitate generation of desirable products. Alloying Cu can alter surface binding strength through electronic and geometric effects, enhancing the availability of surface confined carbon species, and stabilising key reduction intermediates. As a result, significant research has been undertaken to design and fabricate copper-based alloy catalysts with structures that can enhance the selectivity of targeted products. In this article, progress with use of alloying strategies for development of Cu-alloy catalysts are reviewed. Challenges in achieving high selectivity and possible future directions for development of new copper-based alloy catalysts are considered.