Promoting Electrocatalytic Semihydrogenation of Alkynols to Alkenols over a Bimetallic CuAu Alloy Catalyst
Qinghui Ren, Leilei Hao, Jiangrong Yang, Mengyu Lv, Hua Zhou, Zhenhua Li, Haohong Duan, Mingfei Shao
Abstract
Electrocatalytic semihydrogenation of alkynols to alkenols under ambient conditions using H 2 O as a hydrogen source is highly attractive in synthetic chemistry. However, it is still challenging to achieve a high Faradaic efficiency (FE) in a wide potential window. Herein, we reported a bimetallic Cu 3 Au alloy as an efficient catalyst for electrocatalytic semihydrogenation of alkynols to alkenols. Specifically, during semihydrogenation of 2-butyne-1,4-diol (BYD) to 2-butene-1,4-diol (BED), the Cu 3 Au catalyst achieves 12.6-fold greater reaction rate and higher FE compared with pure Cu (99 vs 63%). Moreover, the Cu 3 Au maintains >96% FEs in a wide potential window from −0.19 to −0.59 V vs RHE. We demonstrate that the competitive adsorptions of reactive hydrogen (H*) and BYD greatly influence the semihydrogenation processes. The presence of Au in Cu 3 Au facilitates H* formation and reduces BYD adsorption on Cu, thus enhancing the BYD hydrogenation performance. The Cu 3 Au catalyst affords a broad substrate scope from alkynols to aromatic alkynes, producing the corresponding alkenes in good selectivities. Finally, we coupled BYD semihydrogenation with glycerol oxidation to replace oxygen evolution reaction in a two-electrode system, showing 40% energy saving at 200 mA for BED production and coproduction of valuable formate at the anode, demonstrating an economical manner.