Cobalt-Copper Nanoparticles on Three-Dimensional Substrate forEfficient Ammonia Synthesis via Electrocatalytic Nitrate Reduction
Cobalt-Copper Nanoparticles on Three-Dimensional Substrate forEfficient Ammonia Synthesis via Electrocatalytic Nitrate Reduction
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DOI：
10.1021/acs.jpcc.1c10781
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发表时间：
2022-04-28
影响因子：
3.7
通讯作者：
Wang, Haotian
中科院分区：
文献类型：
--
作者：
Jeon, Tae Hwa;Wu, Zhen-Yu;Wang, Haotian
氨（NH3）是一种用于肥料生产和用作有效氢载体的有价值的化学品。电催化硝酸盐还原反应由于具有良好的反应动力学特性，近年来受到了广泛的关注。然而，这种有前途的策略在大电流密度下受到法拉第效率（FE）低的影响（>100 mA cm-2）和低硝酸盐浓度，因为竞争析氢反应。（Co 1-xCux）纳米颗粒负载在三维基底上，通过电催化硝酸盐还原进行高效和选择性的NH3合成。通常，优化后的Co_（0.5）Cu_（0.5）催化剂在-0.03 V时的NH_3法拉第效率（FE）超过95%，在50 mM硝酸盐时的NH_3分电流密度接近176 mA cm ~（-2），比纯Co和Cu催化剂分别高7.3倍和1.7倍。重要的是，用Cu替代Co能够调节Co催化剂上的起始电位，保持对NH3的高选择性。超过12个循环的稳定性测试证实了该催化剂的长期操作。这项工作提供了一个简单的策略，调整催化剂的元素组成，以获得所需的电催化活性。
Ammonia (NH3) is a valuable chemical for fertilizer productionand for use as an effective hydrogen carrier. Electrocatalytic nitrate reductionhas recently received great attention as an alternative for NH3synthesis due toits kinetically favorable reaction. However, this promising strategy suffers fromlow Faradaic efficiency (FE) at large current density (>100 mA cm-2) and lownitrate concentrations because of the competing hydrogen evolution reaction.Herein, we report a catalyst consisting of earth-abundant cobalt-copper(Co1-xCux) nanoparticles supported on a three-dimensional substrate forefficient and selective NH3synthesis via electrocatalytic nitrate reduction.Typically, the optimized Co0.5Cu0.5catalyst performs at a high NH3Faradaicefficiency (FE) of over 95% at-0.03 V with NH3partial current density of similar to 176 mA cm-2at 50 mM nitrate, which is 7.3- and 1.7-fold higher than that ofpure Co and Cu counterparts. Importantly, replacing Co with Cu enables thetuning of onset potential on Co catalyst maintaining high selectivity toward NH3. A stability test over 12 cycles confirmed the long-term operation of this catalyst. This work offers a facile strategy for tuning the catalyst's elemental composition to attain a desiredelectrocatalytic activity.