Luo Dan, Xie Zhiheng, Chen Shuangqun, Yang Tianyi, Guo Yalin, Liu Ying, Zhu Zhouhao, Gan Liyong, Liu Lingmei, Huang Jianfeng
State Key Laboratory of Coal Mine Disaster Dynamics and Control, Institute of Advanced Interdisciplinary Studies, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China.
College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China.
ACS Nanosci Au. 2024 Aug 8;4(5):349-359. doi: 10.1021/acsnanoscienceau.4c00030. eCollection 2024 Oct 16.
Electrochemical semihydrogenation (ESH) of alkynes to alkenes is an appealing technique for producing pharmaceutical precursors and polymer monomers, while also preventing catalyst poisoning by alkyne impurities. Cu is recognized as a cost-effective and highly selective catalyst for ESH, whereas its activity is somewhat limited. Here, from a mechanistic standpoint, we hypothesize that electron-deficient Cu can enhance ESH activity by promoting the rate-determining step of alkene desorption. We test this hypothesis by utilizing Cu-Ag hybrids as electrocatalysts, developed through a welding process of Ag nanoparticles with Cu nanowires. Our findings reveal that these rationally engineered Cu-Ag hybrids exhibit a notable enhancement (2-4 times greater) in alkyne conversion rates compared to isolated Ag NPs or Cu NWs, while maintaining over 99% selectivity for alkene products. Through a combination of operando and computational studies, we verify that the electron-depleted Cu sites, resulting from electron transfer between Ag nanoparticles and Cu nanowires, effectively weaken the adsorption of alkenes, thereby substantially boosting ESH activity. This work not only provides mechanistic insights into ESH but also stimulates compelling strategies involving hybridizing distinct metals to optimize ESH activity.
炔烃电化学半氢化生成烯烃是一种生产药物前体和聚合物单体的有吸引力的技术，同时还能防止炔烃杂质导致催化剂中毒。铜被认为是一种具有成本效益且选择性高的电化学半氢化催化剂，但其活性在一定程度上受到限制。在此，从机理角度出发，我们假设缺电子的铜可以通过促进烯烃解吸这一速率决定步骤来提高电化学半氢化活性。我们通过使用铜 - 银杂化物作为电催化剂来验证这一假设，该杂化物是通过银纳米颗粒与铜纳米线的焊接过程制备而成。我们的研究结果表明，与孤立的银纳米颗粒或铜纳米线相比，这些经过合理设计的铜 - 银杂化物在炔烃转化率上有显著提高（高出2 - 4倍），同时对烯烃产物的选择性保持在99%以上。通过原位和计算研究相结合，我们证实了由于银纳米颗粒与铜纳米线之间的电子转移而产生的缺电子铜位点有效地削弱了烯烃的吸附，从而大幅提高了电化学半氢化活性。这项工作不仅为电化学半氢化提供了机理见解，还激发了涉及混合不同金属以优化电化学半氢化活性的引人注目的策略。
