Breaking the Energy Linear Relationships between C≡C and C═C Bonds over Porous Intermetallic Pd<sub>2</sub>Ga Metallene Boosting Alkynol Semihydrogenation.

Deng, Kai; Yu, Jiabao; Mao, Qiqi; Yang, Ruidong; Yu, Hongjie; Wang, Ziqiang; Wang, Jianguo; Wang, Liang et al. · ACS Nano · 2026

basic_science · Level V

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Abstract

The electrochemical semihydrogenation (ECSH) of 2-methyl-3-butyn-2-ol (MBY) to 2-methyl-3-buten-2-ol (MBE), using water as a hydrogen source, offers a sustainable pathway for chemical synthesis. However, conventional Pd-based catalysts are limited by the linear scaling relationships (LSRs) between the adsorption energies of C≡C and C═C bonds, often leading to overhydrogenation into 2-methyl-3-butan-2-ol (MBA) and, thus, reduced selectivity toward MBE. In this work, we report a solvothermal approach for synthesizing porous intermetallic Pd<sub>2</sub>Ga (PI-Pd<sub>2</sub>Ga) metallene as a high-performance catalyst for the ECSH of MBY to MBE. The PI-Pd<sub>2</sub>Ga metallene exhibits an optimized electronic structure and an expanded Pd interatomic distance (<i>d</i><sub>Pd-Pd</sub>), which facilitates MBY adsorption, H<sub>2</sub>O dissociation, and MBE* desorption. These distinctive structural properties effectively break the LSRs between C≡C and C═C bonds, resulting in a high MBE selectivity of 96.99%, an MBE Faradaic efficiency (FE<sub>MBE</sub>) of 92.85%, excellent stability, and broad substrate applicability. This work provides a strategy for the rational design and development of efficient catalysts for selective semihydrogenation reactions.