Selectivity Control of Cu Nanocrystals in a Gas-Fed Flow Cell through CO(2) Pulsed Electroreduction.
Selectivity Control of Cu Nanocrystals in a Gas-Fed Flow Cell through CO(2) Pulsed Electroreduction.
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DOI：
10.1021/jacs.1c03443
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发表时间：
2021-05-19
影响因子：
15
通讯作者：
Roldan Cuenya B
中科院分区：
文献类型：
--
作者：
Jeon HS;Timoshenko J;Rettenmaier C;Herzog A;Yoon A;Chee SW;Oener S;Hejral U;Haase FT;Roldan Cuenya B
在这项研究中，我们已经利用了脉冲CO2电还原反应（CO2 RR）的方法来调整在工业相关的电流密度在气体进料的流通池中的产品分布。我们比较了恒电位条件（固定施加电位为-0.7 VRHE）或脉冲电解条件（在氧化电位Ean = 0.6至1.5 VRHE范围内的1 s脉冲，然后在-0.7 VRHE下的1 s脉冲）下Cu催化剂的CO2 RR选择性，并确定了在后一种情况下观察到的提高产物选择性的主要参数。在此，观察到两种不同的制度：（i）对于Ean = 0.9VRHE，我们获得了10%的提高的C2产物选择性（FEC 2 H4 = 43.6%和FEC 2 H5 OH = 19.8%），与−0.7 VRHE下的恒电位CO2 RR相比（FEC 2 H4 = 40.9%和FEC 2 H5 OH = 11%），（ii）而对于Ean = 1.2 VRHE，观察到高CH 4选择性（FECH 4 = 48.3%，恒定-0.7 VRHE时为0.1%）。操作光谱（XAS，Sers）和非原位显微镜（SEM和TEM）的测量结果表明，催化剂选择性的这些差异可以归因于结构修饰和局部pH值的影响。脉冲电解后观察到的催化剂的形态重建与Ean = 0.9 VRHE，包括高度缺陷的界面和晶界的存在下，被发现在C2产品形成的增强中发挥了关键作用。反过来，Ean = 1.2 VRHE的脉冲电解导致催化剂表面附近OH-物质的消耗，导致有利于CH 4生产的OH-贫乏环境。
In this study, we have taken advantage of a pulsed CO2 electroreduction reaction (CO2RR) approach to tune the product distribution at industrially relevant current densities in a gas-fed flow cell. We compared the CO2RR selectivity of Cu catalysts subjected to either potentiostatic conditions (fixed applied potential of −0.7 VRHE) or pulsed electrolysis conditions (1 s pulses at oxidative potentials ranging from Ean = 0.6 to 1.5 VRHE, followed by 1 s pulses at −0.7 VRHE) and identified the main parameters responsible for the enhanced product selectivity observed in the latter case. Herein, two distinct regimes were observed: (i) for Ean = 0.9 VRHE we obtained 10% enhanced C2 product selectivity (FEC2H4 = 43.6% and FEC2H5OH = 19.8%) in comparison to the potentiostatic CO2RR at −0.7 VRHE (FEC2H4 = 40.9% and FEC2H5OH = 11%), (ii) while for Ean = 1.2 VRHE, high CH4 selectivity (FECH4 = 48.3% vs 0.1% at constant −0.7 VRHE) was observed. Operando spectroscopy (XAS, SERS) and ex situ 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 Ean = 0.9 VRHE, including the presence of highly defective interfaces and grain boundaries, was found to play a key role in the enhancement of the C2 product formation. In turn, pulsed electrolysis with Ean = 1.2 VRHE caused the consumption of OH– species near the catalyst surface, leading to an OH-poor environment favorable for CH4 production.
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影响因子：
56.9
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