Jeon Hyo Sang, Timoshenko Janis, Rettenmaier Clara, Herzog Antonia, Yoon Aram, Chee See Wee, Oener Sebastian, Hejral Uta, Haase Felix T, Roldan Cuenya Beatriz
Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany.
J Am Chem Soc. 2021 May 19;143(19):7578-7587. doi: 10.1021/jacs.1c03443. Epub 2021 May 6.
In this study, we have taken advantage of a pulsed CO electroreduction reaction (CORR) approach to tune the product distribution at industrially relevant current densities in a gas-fed flow cell. We compared the CORR selectivity of Cu catalysts subjected to either potentiostatic conditions (fixed applied potential of -0.7 V) or pulsed electrolysis conditions (1 s pulses at oxidative potentials ranging from = 0.6 to 1.5 V, followed by 1 s pulses at -0.7 V) and identified the main parameters responsible for the enhanced product selectivity observed in the latter case. Herein, two distinct regimes were observed: (i) for = 0.9 V we obtained 10% enhanced C product selectivity (FE = 43.6% and FE = 19.8%) in comparison to the potentiostatic CORR at -0.7 V (FE = 40.9% and FE = 11%), (ii) while for = 1.2 V, high CH selectivity (FE = 48.3% vs 0.1% at constant -0.7 V) was observed. spectroscopy (XAS, SERS) and microscopy (SEM and TEM) measurements revealed that these differences in catalyst selectivity can be ascribed to structural modifications and local pH effects. The morphological reconstruction of the catalyst observed after pulsed electrolysis with = 0.9 V, including the presence of highly defective interfaces and grain boundaries, was found to play a key role in the enhancement of the C product formation. In turn, pulsed electrolysis with = 1.2 V caused the consumption of OH species near the catalyst surface, leading to an OH-poor environment favorable for CH production.
在本研究中，我们利用脉冲式一氧化碳电还原反应（CORR）方法，在气体进料流动池中，于工业相关电流密度下调节产物分布。我们比较了在恒电位条件（固定施加电位为 -0.7 V）或脉冲电解条件（在氧化电位范围为 = 0.6至1.5 V下进行1 s脉冲，随后在 -0.7 V下进行1 s脉冲）下的铜催化剂的CORR选择性，并确定了导致后一种情况下产物选择性增强的主要参数。在此，观察到两种不同的情况：（i）与在 -0.7 V下的恒电位CORR（FE = 40.9%和FE = 11%）相比，对于 = 0.9 V，我们获得了10%的C产物选择性提高（FE = 43.6%和FE = 19.8%），（ii）而对于 = 1.2 V，观察到高CH选择性（FE = 48.3%，而在恒定 -0.7 V下为0.1%）。光谱学（XAS、SERS）和显微镜（SEM和TEM）测量表明，催化剂选择性的这些差异可归因于结构修饰和局部pH效应。在用 = 0.9 V进行脉冲电解后观察到的催化剂形态重构，包括存在高度缺陷的界面和晶界，被发现对C产物形成的增强起关键作用。反过来，用 = 1.2 V进行脉冲电解导致催化剂表面附近的OH物种消耗，导致有利于CH生成的贫OH环境。
