Electrocatalytic hydrogenation (ECH) produces high-value chemicals from unsaturated organics using water as a hydrogen source. However, ECH is limited by the low solubility of substrates when operated under aqueous conditions, by electrical losses when performed in organic electrolytes and, in general, by low faradaic efficiency and fastidious work-up. Here, we show that a Pickering emulsion compartmenting organic substrates and aqueous electrolytes in different phases enables efficient ECH at the interface. We designed a construct comprising Pd nanoparticles immobilized on positively charged carbon nanotubes that localizes at the interface to act as both emulsion stabilizer and electrocatalyst. Applied to the ECH of styrene, the system delivers ethylbenzene at high faradaic efficiency (95.0%) and mass specific current density (–148.1 mA \({{{\mathrm{mg}}}}_{{{{\mathrm{Pd}}}}}^{ - 1}\)). The system combines good substrate solubility, high conductivity and simplified product isolation, and has proved applicable to the conversion of various alkenes. This strategy may thus provide alternative solutions to the ECH of substrates with low water solubility, such as bio-oil and bio-crude.

电催化氢化 (ECH) 以水为氢源，从不饱和有机物中生产高价值化学品。然而，ECH 受到在水性条件下操作时底物的低溶解度、在有机电解质中进行时的电损耗以及通常法拉第效率低和后处理苛刻的限制。在这里，我们展示了在不同相中分隔有机底物和含水电解质的皮克林乳液能够在界面处实现高效的 ECH。我们设计了一种包含固定在带正电荷的碳纳米管上的 Pd 纳米颗粒的结构，该碳纳米管位于界面处，可作为乳液稳定剂和电催化剂。应用于苯乙烯的ECH，该系统以高法拉第效率（95.0%）和质量比电流密度（–148.1 mA）输送乙苯\({{{\mathrm{mg}}}}_{{{{\mathrm{Pd}}}}}^{ - 1}\)）。该系统结合了良好的底物溶解性、高电导率和简化的产品分离，并已证明适用于各种烯烃的转化。因此，该策略可以为低水溶性底物（例如生物油和生物原油）的 ECH 提供替代解决方案。