First Authors: Zhiling Tang and Yingli Wang
Corresponding Authors: Yuechang Wei, Min Liu, Yunpeng Liu, and Xi Liu
DOI: 10.1038/s41467-026-68830-5
Research Highlights
(1) Deep synergy between single atoms and sulfur vacancies unlocks a “1 + 1 >> 2” enhancement mechanism for photocatalytic CO2 reduction. The central breakthrough of this study lies in clarifying the intrinsic synergistic coupling between Mn single atoms and sulfur vacancies, rather than attributing the catalytic performance to either structural feature alone. Efficient conversion of CO2 into C2H4 requires both the low-coordination chemical environment created by sulfur vacancies and the active-site characteristics of Mn single atoms. Only through their strong coupling can the performance bottleneck be overcome. The low-coordination environment regulates the electronic structure, strengthens the interaction between the Mn 3d orbitals and the 2π* and 5σ orbitals of CO, and enhances Mn–CO π-backbonding. The Mn single atom, in turn, benefits from this environment by promoting electron transfer, shifting the d-band center upward, and stabilizing key intermediates. This synergistic effect increases the C2H4 yield to 58.9 times that of pristine ZnS and raises selectivity to 99.1%, effectively addressing the dual challenges of low C2-product activity and dominant side reactions, including hydrogen evolution and CO formation, in photocatalytic CO2 reduction.
(2) Low-coordination single-atom sites regulate intermediates throughout the entire reaction pathway, enabling selective C2H4 production. Guided by theoretical calculations, this work proposes a full-pathway intermediate-regulation mechanism dominated by low-coordination single-atom sites, progressively strengthening each step of the photocatalytic CO2 reduction pathway. The low-coordination Mn single-atom sites preferentially lower the energy barrier for CO2-to-*CO conversion while balancing the competitive adsorption of *CO and *H, thereby suppressing premature CO desorption. The sites subsequently promote hydrogenation of *CO to *CHO, followed by asymmetric C–C coupling to form the key *COCHO intermediate. By lowering the energy barrier at each stage, this mechanism provides both theoretical and experimental support for the rational structural design of photocatalysts for CO2 reduction.
(3) Breakthrough catalytic performance with nearly 100% ethylene selectivity. Guided by theoretical calculations, a low-coordination Mn single-atom-embedded ZnS catalyst, denoted Mn1–ZnSv, was developed through a microwave-irradiation-induced targeted defect-engineering strategy. The Mn1–ZnSv catalyst exhibits outstanding photocatalytic performance in CO2 reduction, achieving a C2H4 production rate of 76.6 μmol g-1 h-1 with selectivity approaching 100%. It also maintains stable operation for 200 h without deactivation. The strategy is broadly applicable to other transition-metal single-atom systems, including Fe, Co, Ni, and Cu, offering a new route for efficient conversion of CO2 into multicarbon products.
Introduction
In January 2026, Nature Communications published online the latest research in photocatalytic CO2 reduction from a collaborative team led by Professor Yuechang Wei of China University of Petroleum (Beijing), Professor Min Liu of Central South University, Associate Professor Yunpeng Liu of the Institute of High Energy Physics, Chinese Academy of Sciences, and Professor Xi Liu of Shanghai Jiao Tong University. The study reports that a low-coordination Mn single-atom catalyst enables photocatalytic reduction of CO2 to ethylene with selectivity approaching 100%. The co-first authors are Zhiling Tang and Yingli Wang, and the corresponding authors are Yuechang Wei, Min Liu, Yunpeng Liu, and Xi Liu.
Background
The solar-driven conversion of CO2 into C2+ solar fuels has attracted considerable attention as a promising green solution to global energy demand and climate change. However, achieving high selectivity remains a major challenge because the formation of C2+ products strongly depends on stabilizing carbon-containing intermediates at catalytic active sites to enable efficient C–C coupling. Transition-metal sulfides are considered promising photocatalysts for CO2 reduction because of their tunable d-orbital properties. Nevertheless, these materials generally bind C1 intermediates such as *CO too weakly, leading to premature desorption and preferential formation of C1 products such as CO and CH4 rather than the desired C2+ compounds. In recent years, single-atom catalysts, with atomically dispersed metal centers and well-defined coordination environments, have provided an excellent platform for regulating intermediate adsorption and improving the activity and selectivity of the CO2 reduction reaction. Low-coordination single-atom catalysts can break geometric symmetry, tune the local electronic structure, strengthen the adsorption of carbon-containing intermediates, and promote coupling reactions. Therefore, integrating low-coordination single-atom catalysts into binary sulfides is of great significance for stabilizing *CO and enabling efficient photocatalytic CO2-to-C2+ conversion.
Equipment Used in the Study
Figure Analysis
Figure 1. Schematic illustration of how the coordination environment regulates *CO adsorption.
Figure 2. Theoretical Guidance.
Figure 2 reveals, through theoretical calculations, how low-coordination Mn single-atom sites regulate the key *CO intermediate. Mn1–ZnSv exhibits the lowest energy barrier for CO2-to-*CO conversion, indicating that the low-coordination Mn single-atom structure facilitates CO2 activation and *CO formation. Orbital interactions between the Mn 3d orbitals and the 2π* lowest unoccupied molecular orbital and 5σ highest occupied molecular orbital of *CO are central to regulating *CO adsorption. The low-coordination Mn sites significantly strengthen Mn–CO π-backbonding and enhance *CO adsorption. Introducing these sites also balances the competitive adsorption of *CO and *H, effectively suppressing premature *CO desorption and allowing it to participate in subsequent protonation steps. Electronic-structure analysis shows that the enhanced electronic interaction in Mn1–ZnSv shifts the Mn d-band center upward and increases antibonding-state contributions, thereby promoting the adsorption of reaction intermediates and subsequent C–C coupling. The theoretical screening of catalyst coordination structures provides a basis for the targeted synthesis of highly efficient catalysts and precise regulation of reaction pathways.
Figure 3. Structural Characterization.
Guided by the Mn1–ZnSv structure identified through DFT screening, the researchers successfully prepared a low-coordination Mn single-atom-substituted ZnS catalyst using a microwave-irradiation-induced targeted defect strategy. STEM-EDS elemental mapping and ADF-STEM confirmed the uniform spatial distribution of the constituent elements and the atomic dispersion of Mn. Quantitative ICP-OES and EPR analyses showed that the sulfur-vacancy concentration in the Mn1–ZnSv catalyst closely matched the theoretically optimized configuration obtained by DFT. Structural characterization further demonstrated that Mn was highly dispersed as isolated atoms and predominantly existed in an Mn–S2 coordination environment.
Figure 4. In Situ Spectroscopic Analysis.
Figure 4 systematically explains why Mn1–ZnSv achieves highly selective C2H4 production during photocatalytic CO2 reduction by examining the adsorption and evolution of key intermediates and the overall reaction pathway. In situ DRIFTS measurements showed that, with increasing irradiation time, characteristic absorption bands associated with the key *COCHO intermediate appeared on Mn1–ZnSv, confirming that asymmetric coupling between *CO and *CHO proceeds efficiently to generate *COCHO. Meanwhile, the *COL signal on Mn1–ZnSv was substantially stronger than that on Mn1–ZnS, indicating a stronger ability to adsorb *CO intermediates. Based on these findings, the study proposed a photocatalytic CO2 reduction pathway over Mn1–ZnSv and clarified the key role of low-coordination Mn single-atom sites in stabilizing reaction intermediates, promoting *CO–*CHO coupling, and ultimately enabling highly selective ethylene formation.
Figure 5. Photocatalytic CO2 Reduction Performance.
Figure 5 systematically evaluates the catalytic performance and stability of Mn1–ZnSv for photocatalytic reduction of CO2 to C2H4 under visible light without a photosensitizer or sacrificial agent. Comparative tests show that the low-coordination Mn1–ZnSv catalyst delivers excellent C2H4 activity and selectivity, achieving a C2H4 production rate of 76.6 μmol g-1 h-1 with selectivity approaching 100%. Control experiments and isotope-labeling experiments confirmed that C2H4 formation depends on light, CO2, and H2O, establishing CO2 and H2O as the carbon and proton sources, respectively. The H/D kinetic isotope effect further identified *CHO formation as the rate-determining step. Stability tests over 50 consecutive cycles, together with post-reaction characterization, demonstrated excellent stability of the catalyst structure, electronic state, and Mn coordination environment, with no obvious deactivation.
Conclusion
This study constructed an Mn1–ZnSv photocatalyst containing low-coordination Mn single-atom active sites. Guided by DFT calculations and supported by XAS, in situ spectroscopy, and other characterization techniques, the work systematically clarified the key catalytic mechanism through which the low-coordination environment regulates the electronic state of Mn single atoms, induces anisotropic charge redistribution, and thereby controls *CO adsorption and directional C–C coupling. This mechanism enables efficient photocatalytic CO2 reduction with highly selective C2H4 formation. The synergy between the low-coordination environment and Mn single atoms strengthens interactions between the Mn 3d orbitals and the 2π* and 5σ orbitals of CO, enhances Mn–CO π-backbonding, and shifts the Mn d-band center upward. It also precisely balances the competitive adsorption of *CO and *H, suppressing side pathways such as hydrogen evolution and CO formation while providing new active sites for subsequent C–C coupling. The Mn1–ZnSv catalyst exhibits excellent photocatalytic CO2 reduction performance, nearly 100% selectivity toward C2H4, and long-term catalytic stability for 200 h. The low-coordination single-atom active-site regulation strategy proposed in this work offers a new direction for designing highly efficient and selective photocatalysts for converting CO2 into multicarbon products.
About the Author
Yuechang Wei, born in 1982, is a professor and doctoral supervisor at China University of Petroleum (Beijing). He has been recognized under national-level talent programs administered by the Ministry of Education and the Organization Department of the Central Committee of the Communist Party of China. He received his bachelor's degree in Environmental Engineering from the University of Jinan in 2005, his master's degree in Environmental Engineering from the same university in 2008, and his Ph.D. in Chemical Engineering and Technology from China University of Petroleum (Beijing) in 2012. He currently serves as Secretary-General of the Energy and Environment Professional Committee of the China Energy Society and Executive Deputy Director of the Beijing Key Laboratory of Optical Detection Technology for Oil and Gas. He also serves on the editorial boards of journals including Nanomaterials and Chinese Chemical Letters.
His research focuses on the purification of soot particulates from motor-vehicle exhaust, photocatalytic CO2 reduction, and C1 resource conversion. He has published more than 220 SCI-indexed papers in journals including Nature Communications and Energy & Environmental Science, with more than 12,000 citations and an H-index of 65. He has led more than ten national, provincial, and ministerial research projects and holds 37 Chinese invention patents. He has received five scientific and technological awards, including the First Prize for Basic Research Achievements from the Chemical Industry and Engineering Society of China. He has also been selected for the Beijing Nova Program and several talent programs at China University of Petroleum (Beijing), including Distinguished Scholar, Outstanding Young Scholar, and Young Top-Talent programs. He received the Beijing Outstanding Doctoral Dissertation Award and the Young Scientist Award from the Council of the International Association of Catalysis Societies in 2020.
Reference
Tang, Z., Wang, Y., Qin, T., et al. Near-unity CO2-to-ethylene photoconversion over low-coordination single-atom catalysts. Nature Communications 17, 2081 (2026). https://doi.org/10.1038/s41467-026-68830-5
Founded in 2006, Beijing Perfectlight Technology Co., Ltd. is a National High-Tech Enterprise, a Zhongguancun High-Tech Enterprise, and one of Beijing's first recognized Specialized, Sophisticated, Distinctive, and Innovative enterprises. The company is certified under the ISO 9001, ISO 14001, and ISO 45001 management systems, and its after-sales service has received a five-star rating under GB/T 27922-2011. Perfectlight specializes in the research, development, manufacturing, sales, and service of intelligent, high-precision, and high-performance instruments and integrated solutions. Its product portfolio spans more than ten categories, including light sources, photochemical, photoelectrochemical, photothermal, and thermocatalytic systems, characterization and testing platforms, R&D and scale-up equipment, and photosynthesis systems, supporting applications from fundamental research and laboratory-scale studies to pilot testing and industrial scale-up. Perfectlight serves universities, research institutes, and industrial customers, with a focus on renewable energy, pharmaceutical synthesis, fine chemicals, and advanced materials. Its products are used in more than 3,000 laboratories across nearly 50 countries and have supported the publication of more than 9,000 SCI-indexed papers. The company has led or participated in the development of national and industry standards, undertaken projects under China's National Key Research and Development Program, obtained multiple core intellectual-property rights and Beijing New Technology and New Product certifications, and helped industrial customers establish photochemical production lines at both tonne and hundred-tonne scales.
The equipment used in this study was the Labsolar-6A All-Glass Automatic Online Trace Gas Analysis System. The system integrates automated control software for straightforward operation and offers strong compatibility. By replacing the reactor, it can perform trace-gas detection for photocatalytic, photothermal catalytic, electrocatalytic, and PEC photoelectrochemical reactions.
