In the process of global industrialization, the massive emission of carbon dioxide has become a serious challenge causing global climate change. Therefore, developing efficient CO2 conversion technologies to produce high-value-added chemicals holds significant strategic importance. Among various technological approaches, the electrocatalytic carbon dioxide reduction reaction (CO2RR) is regarded as a highly promising means to achieve carbon neutrality due to its environmental friendliness and high potential for integration with renewable energy. Among various metal catalysts, copper-based catalysts stand out as the most promising candidate for large-scale application because of their unique ability to produce multi-carbon products and their low cost advantage.

However, copper-based catalysts still face two major core challenges in practical applications: low selectivity and poor stability. On the one hand, due to the extreme complexity of the carbon-carbon coupling process and the severe competing hydrogen evolution reaction, it is difficult for catalysts to maintain high ethylene selectivity at industrial-level current densities. On the other hand, under the high overpotential conditions required for producing multi-carbon products, copper-based catalysts are highly prone to structural reconstruction, fragmentation, or dissolution. This dynamic instability severely shortens the catalyst's service life and hinders its industrialization. Therefore, developing novel copper-based catalytic systems that can simultaneously achieve high selectivity and long-term durability is a bottleneck problem that urgently needs to be addressed in this research field.

To address the above issues, a team from Fuzhou University and other institutions conducted systematic research using ZEPTOOLS' in-situ TEM measurement system. By introducing a nitrogen-rich Schiff base network to synergistically modify the surface of copper nanoparticles, they successfully developed a novel electrocatalyst capable of achieving both high ethylene selectivity and excellent durability at high current densities.

Title: Synergistic surface modification of Cu with schiff-base networks for high selectivity and durability in CO2-to-C2H4 electroreduction
Journal: Nature Communications
URL: doi.org/10.1038/s41467-026-70595-w

To address the issue of active site deactivation in copper-based catalysts, the research team developed a unique synergistic modification strategy. By coupling copper nanoparticles with different crystal facets with a nitrogen-rich Schiff base network (SNW), they constructed closely contacted core-shell or partially coated structures. The experiments successfully synthesized copper nanoparticles in three morphologies—cubic, spherical, and tetrahedral—and utilized the high CO2 adsorption capacity of SNW to form a local reactant enrichment zone around the active sites. This structural design not only optimized the charge distribution on the copper surface through electronic interactions but also leveraged the hydrophobicity of SNW to reduce direct erosion of the metal surface by the electrolyte, thereby establishing the material foundation for improving reaction selectivity and structural stability.

In the electrochemical performance evaluation, the researchers found that the ethylene yield of the catalyst exhibited a significant crystal-face dependence, with the cubic copper component exposing the (200) crystal facet playing a dominant role in product conversion. Experimental results confirmed that the SNW-modified cubic copper catalyst achieved a Faradaic efficiency of 71.2% for ethylene at a high current density of 265 mA per square centimeter, a value far exceeding that of unmodified pure copper materials and other morphology control groups. This performance leap is attributed to the synergistic effect between SNW and the copper (200) crystal facet, which effectively suppresses the generation of byproducts such as carbon monoxide and hydrogen by lowering the coupling energy barrier of key intermediates.

To reveal the dynamic stability of the catalyst in a real reaction environment, the research team employed real-time monitoring with high spatiotemporal resolution, in which the in-situ static liquid electrochemical holder provided by ZEPTOOLS played a key role. Using transmission electron microscopy equipped with the ZEPTOOLS in-situ holder, the researchers clearly observed that under strong reducing potential, pure copper particles undergo severe corrosion, reconstruction, and even dissolution starting from the corners, while the SNW-protected catalyst maintained its morphological integrity. This direct microscopic evidence accurately demonstrates that the organic network layer acts as a chainmail-like protective barrier, significantly extending the service life of the catalyst under harsh operating conditions through physical shielding and electronic stabilization mechanisms.

During the in-depth mechanistic investigation, the study combined in-situ infrared spectroscopy with theoretical simulation techniques to systematically reconstruct the molecular pathway of carbon dioxide conversion to ethylene. Spectroscopic analysis captured key carbon-containing intermediate signals, confirming that the presence of SNW accelerates the hydrogenation steps and promotes the carbon-carbon coupling process. Density functional theory calculations further revealed that charge transfer from copper to SNW makes the nitrogen sites at the interface ideal adsorption centers, significantly reducing the free energy of the rate-determining step. This explains, from both thermodynamic and kinetic perspectives, why the catalytic system can achieve both high efficiency and high stability.

ZEPTOOLS, as a Chinese high-end precision instrument company, is a leading supplier of in-situ electron microscopy characterization solutions. The PicoFemto series of in-situ transmission electron microscopy characterization solutions have successively provided technical support for major research achievements of users both domestically and internationally. The figure below shows the ZEPTOOLS in-situ TEM sample holder product used in this research achievement: