Traditionally, the conversion of propane to propene has relied on expensive catalysts that contain precious metals such as platinum or chromium. These metals, while effective, contribute to high operational costs and have negative environmental impacts. In light of this, cobalt-based catalysts have emerged as a promising alternative. Cobalt not only provides superior catalytic activity but also possesses the capacity to selectively activate carbon-hydrogen (C-H) bonds in propane and other alkanes.

Despite the advantages of cobalt-based catalysts, the mechanisms behind the dehydrogenation of propane remain a subject of intense debate among chemists. The nature of the active species involved—whether it’s Co0, Co2+, or Co3O4—has generated significant discussion in the literature. One prevailing theory suggests that the isolated Co2+Ox species present on the surfaces of supports like silica or zeolites are primarily responsible for facilitating the PDH reaction. Conversely, metallic Co0 species are believed to catalyze the cracking of propane, leading to the formation of undesirable by-products rather than the desired propene.

Nonetheless, compelling evidence suggests that well-dispersed Co0 species formed in situ from CoOx can selectively dehydrogenate propane to propene under the right conditions. This transformational approach counts on the effective management of catalyst morphology and the operational environment to control the catalytic activity and selectivity towards desired products. The challenge remains to elucidate the conditions that favor the formation of active Co0 sites while suppressing parallel reactions that lead to carbon deposition and methane production.

Recent studies led by Professor Evgenii V. Kondratenko from the Leibniz Institute for Catalysis in Germany shed new light on this critical aspect of catalytic science. Conducting research on cobalt oxide (CoOx) species supported on silicalite-1 zeolite, their findings reveal the dynamic behavior of these species under reaction conditions. The restructuring and transformation of CoOx during the dehydrogenation process are pivotal in understanding how selectivity can be controlled in PDH reactions.

The team discovered that the lattice oxygen of oxidized CoOx serves a dual purpose: it oxidizes propane not just to propene but also to carbon oxides. Interestingly, larger CoOx species tend to favor the latter reaction pathway, which is less desirable in propene production. This oxidation process typically occurs rapidly during the initial seconds of propane exposure under PDH conditions, which can detract from overall selectivity and yield.

As CoOx is reduced to form Co0 species during the reaction, it becomes critical to optimize these active sites to favor propene production. Research indicates that small Co0 particles, if covered with a carbon-containing layer, can mitigate deep dehydrogenation and cracking reactions, thus enhancing selectivity for propene. This observation has profound implications for catalyst design, as it suggests that controlling the surface chemistry of Co0 could drastically improve the efficiency of the PDH process.

In summary, the work conducted at the Leibniz Institute marks a significant advancement in the field of catalysis, particularly in refining the mechanisms of the PDH process. The ability to manipulate the structure of CoOx species to favor propene formation could potentially revolutionize the landscape of propene production, making it both economically viable and environmentally sustainable. This research was published in the esteemed Chinese Journal of Catalysis, where it joins a growing body of literature aiming to redefine catalysis in the context of modern chemical engineering challenges.

The overarching goal in advancing these catalytic systems is to create methodologies that are not only cost-efficient but also minimize ecological footprints. As global industries strive toward more sustainable practices, the ongoing research into cobalt-based catalysts for PDH continues to be a promising field, combining practical applications with fundamental scientific inquiry.

By emphasizing the importance of selectivity control through the innovative management of catalyst morphology, the research community can lay the groundwork for the development of next-generation catalysts. This evolution in catalyst science may ultimately lead to transformative practices in the production of valuable petrochemicals, aligning industrial processes with the pressing needs of environmental stewardship.

As the world continues to navigate the challenges of resource management and sustainable chemical production, pioneering investigations into cobalt catalysts for propane dehydrogenation will undoubtedly play a critical role in shaping future practices in the chemical industry.

Subject of Research: Cobalt-based catalysts for propene production
Article Title: Understanding the reaction-induced restructuring of CoOx species in silicalite-1 to control selectivity in non-oxidative dehydrogenation of propane
News Publication Date: 24-Jul-2025
Web References: Chinese Journal of Catalysis
References: None
Image Credits: Credit: Chinese Journal of Catalysis

Keywords

Applied sciences and engineering

The research, recently published in Nature Chemistry, details an innovative reaction pathway where the Cu₁/TiO₂ single-atom catalyst, when exposed to water vapor and illuminated by light, facilitates propane dehydrogenation at temperatures as low as 50 to 80 degrees Celsius. This marks an unprecedented breakthrough, indicating that the PDH process can be driven efficiently by photo-thermo catalytic techniques rather than relying solely on traditional thermal energy inputs. The incorporation of water vapor into the reaction environment not only reduces the thermal barrier but also catalytically participates in the reaction mechanism without being consumed, presenting a paradigm shift in how endothermic dehydrogenation reactions might be understood and engineered.

At the heart of this transformation is the unique role played by the copper single atoms dispersed on the titanium dioxide support. These individual copper atoms act as highly active catalytic centers that synergize with water molecules and light energy. Under illumination, the Cu₁/TiO₂ catalyst undergoes photocatalytic water splitting, generating reactive hydrogen and hydroxyl species on the catalyst surface. Hydroxyl radicals then engage directly with propane molecules, abstracting hydrogen atoms and resulting in the formation of propylene and water. This reaction mechanism starkly contrasts with conventional PDH and oxidative dehydrogenation pathways, which typically depend on high thermal activation and often create unwanted byproducts or suffer from catalyst deactivation.

In continuous-flow fixed-bed reactor experiments, the team achieved remarkable reaction rates, reaching up to 1201 micromoles per gram of catalyst per hour, a metric that underscores both the efficiency and potential scalability of this method. Operating near room temperature and under water vapor, the novel photo-thermo catalytic system minimizes energy consumption, offering a sustainable alternative to the existing high-temperature PDH processes that dominate the petrochemical industry. This innovation addresses long-standing industrial challenges and opens new avenues for more energy-efficient production of propylene, a cornerstone molecule for plastics, fibers, and rubbers worldwide.

Beyond propane, this method’s versatility extends to other light alkanes such as ethane and butane, underscoring the broad applicability of the copper single-atom catalytic system combined with water and light. The researchers demonstrated that the catalyst system could directly harness sunlight as an energy source, favoring the integration of renewable energy into hydrocarbon conversion processes. Such developments align closely with global efforts to reduce carbon footprints and transition towards cleaner, solar-driven chemical manufacturing.

Photocatalysis traditionally involves light-induced electron-hole pair generation to drive chemical reactions, but this study presents a nuanced hybrid of photo-thermo catalysis that leverages both photon energy and moderated thermal inputs to break the tight C–H bonds in propane molecules. The generation of hydroxyl radicals plays a pivotal role in this catalytic mechanism, acting as highly reactive intermediates that selectively strip hydrogen atoms from propane, thus facilitating the formation of propylene with minimal side reactions. Importantly, water’s role as a catalytic medium rather than a reactant underpins a sustainable approach that avoids excessive reagent consumption and waste formation.

This discovery not only offers a path to more efficient and environmentally benign propylene production but also lays foundational knowledge for designing next-generation heterogeneous catalysts that can operate under ambient conditions. The insights gained into the single-atom copper catalytic sites pave the way for rational design of atomically dispersed catalysts tailored for specific photochemical and thermochemical processes in the energy and chemical industries. In essence, controlling catalytic activity at the atomic scale, aided by light and water, promises to revolutionize how complex molecular transformations are achieved in the future.

Moreover, the implication of utilizing solar energy directly to drive PDH aligns with the growing imperative to decarbonize the chemical industry, often cited as a major contributor to global carbon emissions. The ability to carry out industrial-scale chemical synthesis powered by sunlight and water vapor could dramatically reduce reliance on fossil fuel combustion, thus steering chemical manufacturing toward more sustainable paradigms. Such technologies have vast potential applications, ranging from portable chemical reactors to decentralized production units harnessing natural sunlight.

Professor LIU Xiaoyan, a corresponding author of the study, emphasized that this research not only introduces a breakthrough catalytic process but also establishes an important conceptual framework for high-temperature reactions driven principally by solar energy. This work signifies a vital stride toward marrying catalysis with renewable energy inputs, demonstrating how fundamental scientific insights can catalyze disruptive technologies in petrochemical processing. The combined expertise of the Dalian and Shanghai research teams exemplifies the vibrancy of multidisciplinary collaboration required to tackle energy-intensive industrial challenges.

The detailed mechanistic understanding revealed in this study also has profound implications for the future design of catalysts that leverage single-atom active sites, a field garnering immense attention due to the exceptional selectivity and activity such catalysts offer. By elucidating the synergistic effects between copper single atoms, water-derived reactive species, and light, researchers can now conceive tailored catalysts for a variety of hydrocarbon conversions previously limited by thermodynamic or kinetic constraints.

In conclusion, the photo-thermo catalytic system employing a copper single-atom catalyst under water vapor illumination inaugurates a new frontier in alkane dehydrogenation chemistry. It opens sustainable and energy-efficient avenues for producing vital chemical intermediates under mild, near-ambient conditions. By exploiting water as a catalytic medium and solar energy as a clean power source, this research points the way toward greener chemical manufacturing processes, aligning with international aspirations for sustainable industrial development and carbon neutrality in the decades to come.

Subject of Research: Not applicable

Article Title: Light-driven propane dehydrogenation by a single-atom catalyst under near-ambient conditions

News Publication Date: 21-Mar-2025

Web References:

• https://www.nature.com/articles/s41557-025-01766-3
• http://dx.doi.org/10.1038/s41557-025-01766-3

References:
Zhang Tao, Wang Aiqin, Gao Yi, and colleagues, "Light-driven propane dehydrogenation by a single-atom catalyst under near-ambient conditions," Nature Chemistry, March 2025.

Image Credits: Dalian Institute of Chemical Physics (DICP)

Keywords

Catalysis, Dehydrogenation