Zhang Yusheng, Cai Zhao, Zhao Yuxin, Wen Xuemei, Xu Wenwen, Zhong Yang, Bai Lu, Liu Wen, Zhang Ying, Zhang Ying, Kuang Yun, Sun Xiaoming
State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
Nanoscale Horiz. 2019 Mar 1;4(2):490-494. doi: 10.1039/c8nh00259b. Epub 2018 Nov 28.
Copper is one of the most efficient electrocatalysts for switchable carbon dioxide conversion, but the design of an advanced Cu-based catalyst with high selectivity while suppressing hydrogen evolution remains a great challenge. Herein, we use Cu nanowires (Cu NWs) as the starting materials and polytetrafluoroethylene (PTFE) as the surface modifier to make a superaerophilic electrode using a wettability control strategy. This strategy allows tuning of the selectivity of the CO reduction reaction (CORR) and a decrease of the hydrogen evolution rate simultaneously by facilitating the supply of CO reactants and inhibiting the adsorption of water (protons). The transferring point from a pinning to bursting state turned out to be the optimized condition leading to the highest CORR faradaic efficiency without significant interference of current density. The optimized superaerophilic Cu NW catalyst showed CO-selectivity with a Faraday efficiency of 71% at -0.4 V vs. RHE and HCOOH-selectivity with a Faraday efficiency of 68% at -0.6 V vs. RHE. Moreover, the accelerated gas and ion diffusion and homogenized reactions also avoided accumulative damage on the surface of the Cu NWs and enhanced the stability of the Cu catalyst. This wettability tuning strategy provides a facile and efficient way to optimize the gas and ion diffusion layers, therefore promoting the performance of the CORR. This strategy potentially can be extended to the design of other gas consumption electrocatalysts.
铜是用于可切换二氧化碳转化的最有效的电催化剂之一，但设计一种在抑制析氢的同时具有高选择性的先进铜基催化剂仍然是一个巨大的挑战。在此，我们以铜纳米线（Cu NWs）为起始材料，聚四氟乙烯（PTFE）为表面改性剂，采用润湿性控制策略制备了一种超亲气电极。该策略通过促进一氧化碳反应物的供应和抑制水（质子）的吸附，实现了对一氧化碳还原反应（CORR）选择性的调节，并同时降低了析氢速率。从钉扎状态到爆发状态的转变点被证明是优化条件，可实现最高的CORR法拉第效率，且电流密度无显著干扰。优化后的超亲气铜纳米线催化剂在相对于可逆氢电极（RHE）为-0.4 V时表现出一氧化碳选择性，法拉第效率为71%；在相对于RHE为-0.6 V时表现出甲酸选择性，法拉第效率为68%。此外，加速的气体和离子扩散以及均匀化反应还避免了铜纳米线表面的累积损伤，提高了铜催化剂的稳定性。这种润湿性调节策略提供了一种简便有效的方法来优化气体和离子扩散层，从而提升CORR的性能。该策略有可能扩展到其他气体消耗型电催化剂的设计中。
