Revamped Catalyst Design for Electrocatalytic Semihydrogenation of Acetylene

Recently, the research group of Professor Zeng Jie of Hefei National Research Center for Physical Sciences in Microscale and University of Science and Technology of China (USTC), in collaboration with Professor Xia Chuan and research team Zheng Tingting of University of Electronic Science and Technology of China, uncoordinated catalyst of copper nanoparticles to achieve semihydrogenation of acetylene with high self-efficacy and efficiency. Research published in Nature Communications.

Ethylene is a prominent substance in the chemical industry. Typically, the industrial production process of ethylene (C₂h₄) deterministically yields 0.5%-3% acetylene (C₂h₂) a by-product that irreversibly poisons Ziegler-Natta catalysts, leading to decreased activity.

Therefore, it is important to remove C₂h₂ impurities in ethylene production. The conventional semi-thermohydrogenation of C₂h₂ It requires high temperature, high pressure, and an expensive palladium-based catalyst, which limits its further development.

The decreasing cost of electrostimulation stimulated the development of electro-acetylene semihydrogenase (EASH) using copper-based catalysts as an alternative. However, previous copper-based catalysts still suffered from side reactions, leading to unsatisfactory purification.

To solve this problem, the team first synthesized non-coordinated Cu NDs as catalysts by in situ reduction. When tested for activity under pure acetylene flow, uncoordinated copper NDs achieved Faradaic efficiencies in excess of 90% over a wide range of current densities, reaching a peak of 95.6% at a current density of −350 mA cm.^-2. In addition, in situ spectroscopy revealed a lower energy barrier for uncoordinated Cu NDs catalysts.

Membrane electrode assembly (MEA) reactors have the advantages of low resistance, low power consumption and compact configuration. Therefore, the team designed a two-electrode MEA reactor for continuous generation of the C-grade polymer₂h₄.

In the 25 cm performance appraisal test² The MEA reactor can fully convert 0.5% C₂h₂ to C.₂h₄ At various flow rates from 10 to 50 standard cubic centimeters per minute (sccm). With increasing flow rate, the selectivity of C₂h₄ Show an upward trend. The team has been able to continuously synthesize the C-grade polymer₂h₄ for 130 hours under a flow rate of 50 cubic meters per minute with little performance decay (residual C₂h₂ Less than one part per million, the cell voltage is maintained at -1.89 volts).

This work achieved high efficiency EASH for polymer grade ethylene production through catalyst development, reaction mechanism study and reactor design, which provides prospects for future development of electrocatalytic ethylene purification.