Premium
Synthesis and Characterization of Degradation‐Resistant Cu@CuPd Nanowire Catalysts for the Efficient Production of Formate and CO from CO 2
Author(s) -
Hou Yuhui,
Erni Rolf,
Widmer Roland,
Rahaman Motiar,
Guo Huizhang,
Fasel Roman,
MorenoGarcía Pavel,
Zhang Yucheng,
Broekmann Peter
Publication year - 2019
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201900752
Subject(s) - bimetallic strip , formate , catalysis , materials science , single displacement reaction , selectivity , faraday efficiency , galvanic cell , electrochemistry , palladium , inorganic chemistry , nanoparticle , chemical engineering , copper , degradation (telecommunications) , chemistry , nanotechnology , electrode , metallurgy , organic chemistry , telecommunications , computer science , engineering
Not only are the product selectivity and the activity of electrocatalysts important aspects for the evaluation of their overall performance, but also their stability and resistance against structural and compositional degradation during the electrocatalytic reaction. Palladium nanoparticles (Pd‐NPs) have already been identified as superior electrocatalysts for the electrochemical conversion of CO 2 into formate at extremely low overpotentials and into carbon monoxide (CO) at medium overpotentials. However, these catalysts suffer from fast degradation, owing to irreversible CO poisoning of Pd reaction sites. Herein, we report on nanoparticulate bimetallic Pd 45 Cu 55 catalysts, demonstrating a similar selectivity and activity to the pure Pd‐NPs, but showing additional superior degradation stability and resistance against CO poisoning. Pd 45 Cu 55 catalysts were synthesized by means of a galvanic displacement reaction using copper nanowires (Cu‐NWs) as the starting material (template) for the galvanic displacement reaction, which leaves a surface‐confined alloy film and respective nanoparticles on the Cu‐NW template (denoted as Cu@CuPd‐NWs). A faradaic efficiency (FE) up to FE formate ≈80 % can be achieved at −0.3 V vs. RHE, thus clearly proving that the ‘anomalous’ CO 2 reaction mechanism via the CO 2 hydrogenation pathway, discussed for pure Pd‐NPs, can also be transferred to Pd‐based bimetallic systems. At medium overpotentials, the product selectivity changes from selective formate to predominant CO formation with a maximum faradaic efficiency of FE CO =86 %. Extended CO 2 electrolyses demonstrate, for both formate and CO production, superior degradation stability, for example, FE CO remains at 85 %±5 % for the duration of 20 h. For the first time, identical location high‐angle annular dark‐field scanning transmission electron microscopy (IL‐HAADF‐STEM) in combination with energy‐dispersive X‐ray spectrometry and identical location scanning electron microscopy (IL‐SEM) were applied to demonstrate the compositional and structural stability of the bimetallic catalyst under CO 2 reduction conditions.