Constructing a CuZn Alloy from a Metal–Organic Framework via Electrochemical Reduction for Electrocatalytic Alkyne Semihydrogenation

The selective semihydrogenation of alkynes to alkenes is a fundamental reaction in organic synthesis. However, developing efficient, cost-effective, and uniformly distributed nonprecious alloy electrocatalysts remains a significant challenge. In this study, we report the design and synthesis of a uniformly distributed nonprecious CuZn alloy catalyst through the direct electrochemical reduction of a presynthesis CuZn-BTC metal–organic framework (MOF) precursor. Experimental results combined with theoretical calculations reveal that the incorporation of Zn facilitates the electron transfer to Cu. This modification lowers the Cu d-band center, weakening the adsorption strength of alkenes, which enhances the alkenes selectivity. Furthermore, the presence of Zn breaks the scaling relationship between alkynes and their hydrogenation intermediates, promoting efficient alkyne conversion. Zn also effectively suppresses the competitive hydrogen evolution reaction (HER), further boosting the catalytic efficiency. At the optimal potential of −1.40 V vs Hg/HgO, the catalyst achieves 94% alkyne conversion, 98% alkene selectivity, and 49.4% alkene Faradaic efficiency. Additionally, the catalyst exhibits good stability, retaining its structure integrity and catalytic performance after ten reaction cycles. The catalyst also demonstrates broad applicability in the semihydrogenation of various functionalized alkynes. Among the reported Cu-based catalysts, the CuZn alloy catalyst exhibits relatively better performance in the semihydrogenation of alkenes. This study offers an approach for designing highly efficient bimetallic electrocatalysts with uniformly distributed active sites, addressing the challenges faced by non-noble-metal catalysts in electronic and geometric structure optimization.