Antonio José Martín

Achieving selective polyolefin waste hydrogenolysis into fuels and chemicals requires architectures that disrupt Ru─Ru ensembles without compromising the intrinsic activity of the state‐of‐the‐art Ru catalyst. While metal modifiers can beneficially tune selectivity, they have been shown for high promoter‐metal contents, with associated penalties in structural definition and potential practicality. Here, we engineer cobalt speciation on Ru through impregnation to disclose how promotion spans the entire compositional space realizing a titania‐supported Co ₁ /Ru single‐atom alloy catalyst (Co ₁₀ Ru ₉₀ , 3 mol% total metal content) that resolves these trade‐offs. Ex situ and operando analyses reveal that these bimetallic ensembles containing Ru─Co─Ru sites display a distinctively high barrier for over‐hydrogenolysis at late reaction stages while preserving the intrinsic activity of Ru. As a result, virgin polypropylene and post‐consumer waste were almost fully converted with a consistently high C ₁₁₊ yield of up to 60% (78% total liquids), compared to <5% over the monometallic Ru counterpart. Process‐level simulations predict economically viable and environmentally sustainable operation enabled by the high single‐pass yields of long‐chain liquid products. These results reveal a wide compositional landscape for Ru promotion and recommend its second‐metal‐content single‐atom alloy limit as the most promising strategy for further catalyst design efforts.

Polyolefins are essential plastics to modern life yet create mounting sustainability challenges. Chemical recycling technologies are key but often require harsh conditions, costly hydrogen, noble metals, or complex catalysts with challenging design. We report hydrogen- and solvent-free depolymerization of polypropylene consumer goods at 240 °C, achieving >80% yield into gasoline hydrocarbons with stable performance. A library of tungstated zirconia catalysts synthesized by flame spray pyrolysis with controlled tungsten speciation enables correlating performance with the density of W–O–Zr ensembles prevalent in sub-nanoclusters, with W:Zr = 1:9 emerging as optimal. These acid sites formed during reaction mediate internal hydrogen transfer and selective backbone C–C scission, as deduced from operando spectroscopy. Life cycle and technoeconomic studies, benchmarked against hydrotreatment-based recycling in a harmonized framework, indicate competitive environmental and economic advantages. Together, this work establishes this route’s promise and underscores the value of precision catalyst synthesis in polyolefin valorization.

Aligning catalyst development with process-level sustainability metrics is crucial for advancing the chemical recycling of plastics. We bridge both elements to study hydrogenolysis of high-density polyethylene and report Ru–Ni alloy nanoparticles supported on titania that yield up to 55% liquid alkane products (C6–C45) under optimized conditions. Operando spectroscopy reveals Ru–Ni alloy sites formed in situ, and temperature-programmed experiments suggest an enhanced preference for internal instead of terminal scission over the bimetallic catalysts. By integrating these experimental insights with life cycle and techno-economic analyses, we identify a minimum average-chain-length threshold of C11 for product distributions as a catalyst design guideline to reconcile environmental and economic objectives, illustrating the value of bridging catalyst design and process-level analyses.

A literature-mining analysis of 25 years of Green Chemistry shows how prevention-based foundations are being enriched by evidence and systems thinking, inviting broader communities to shape the field's next chapter.

Assessing the sustainability of plastic chemical recycling requires realistic feedstocks and catalysts designed within sustainability-led frameworks (Plastic-to-X). We link catalyst design and systems analysis to study hydrogenolysis of high-density polyethylene (virgin and bottle caps; M_w = 100–200 kDa). We report Ru–Ni alloy nanoparticles (3–4 nm) supported on titania that yield up to 55% liquid C₆–C₄₅ products under optimized conditions, whereas monometallic Ru produces virtually no liquids Operando spectroscopy and simulations reveal structure sensitivity: backbone scission follows dehydrogenation and hydrogenation cycles at defective alloy sites formed in situ. Integrating these mechanistic insights with life cycle and techno-economic analyses indicates profitable processing of plastic caps over the optimal catalyst (2.5 wt% Ru, 5 wt% Ni) with substantially lower CO₂ emissions even when using green H₂. Furthermore, within the Plastic-to-X framework, we identify a minimum average chain length threshold of C₁₁ for product distributions as a critical design metric to reconcile environmental and economic objectives.

This study models a future methanol economy where combining biomass, biogas, and air-captured CO ₂ achieves net-zero emissions at about 32 USD ₂₀₂₅ per person per month, close to Paris Agreement-aligned costs while delivering deeper emission cuts.

Platform chemicals—such as olefins, ammonia, aromatics, and methanol—serve as fundamental building blocks for the chemical industry. At the same time, they account for 4% of global CO₂ emissions, highlighting the need for renewable feedstocks, renewable energy, or other alternative approaches to develop more sustainable production routes toward carbon neutrality. Despite substantial research output, we lack a holistic understanding of where innovation is heading. This gap leaves research planning and policy decisions without a quantitative basis for understanding the directions of innovation. A better understanding of how they differ between platform chemicals is critical for delineating policies and strategic plans toward a net-zero future. Our study addresses this gap by providing unprecedented clarity on global research trends in platform chemicals spanning the last three decades since the establishment of the Green Chemistry principles and other subsequent sustainability approaches for chemical systems, showing the rise, reign, and retreat of topics in this area. For this purpose, we develop a novel approach by integrating topic modelling, generative AI, and expert judgment to analyse >90 000 research articles from Scopus, identifying 62 distinct research topics and tracking their temporal and geographical trends. Our results reveal different innovation patterns across the four platform chemicals. Driven by the concepts of an ammonia or methanol economy, research output has increased for these platform chemicals by a factor of 17 and 6 between 2000 and 2024, respectively. This growth has been led by new strategies like photo- and electrochemical routes, which now account for approximately 65% of ammonia-related research. For olefins and aromatics, innovation patterns show less momentum as research has rather focused on optimising available technologies. Reliance on existing alternative routes (based on renewable methanol) and olefins and aromatics’ molecular complexity could explain this lower momentum. Our quantitative findings can help define research priorities for green chemistry and derive the implications of emerging technological trends on industrial systems regarding future electricity, biomass, and feedstock demand.

Establishing the sustainability of chemical recycling of plastics demands prioritizing realistic feedstocks while advancing catalyst design informed by sustainability-driven frameworks, as envisioned in the ‘Plastic-to-X’ concept. The main outcome of this work is bridging experimental and system-level approaches to explore the interplay of catalyst composition, structure, and hydrogenolysis performance using high-density polyethylene (M_w = 100, 200 kDa) in virgin and in plastic caps form. By incorporating nickel as a modifier to the ruthenium active phase (100% gas yield), we developed titania-supported Ru-Ni alloy nanoparticles (ca. 5 nm) producing 25% of liquid (C₆–C₄₅) products. Structure sensitivity is elucidated through experiments and simulations, disclosing that energetically favorable backbone scission is preceded by dehydrogenation and hydrogenation cycles over defective alloy sites. Integrating these findings with life cycle and technoeconomic analyses, we predict the potential for profitable processing of plastic caps using the optimal catalyst (2.5 wt% Ru and 5 wt% Ni) with significantly reduced CO₂ emissions even when using green hydrogen. Furthermore, and within the ‘Plastic-to-X’ framework, we identify a minimal average chain length threshold of C₁₁ for product distributions as a key metric to reconcile environmental and economic objectives.

Renewable‐powered electrocatalytic CO₂ conversion to long‐chain hydrocarbons represents a sustainable path to produce chemicals and fuels. However, recently discovered systems still lack C–C coupling capabilities required to yield longer, more valuable carbon chains. This study reports cobalt catalysts with a focus on a Co₃O₄‐derived material for the selective conversion of CO₂ to C₁–C₇ hydrocarbons, following an Anderson–Schulz–Flory distribution. The obtained chain growth probability (α) of 0.54 substantially exceeds that of any other known electrocatalyst, which ranged from 0.2 to 0.4. Detailed in situ characterization and simulations indicated that Co‐Co₃O₄ interfaces, formed in situ during CO₂ electrolysis, are the active sites that promote enhanced chain growth. To prevent overreduction that causes the deactivation of these interfacial sites, the electrode is exposed to intermittent short reoxidation cycles during CO₂ electrolysis. Consequently, the catalyst regained its oxidic phase and ability to form hydrocarbons. Overall, this study opens new frontiers in the one‐step conversion of CO₂ into multi‐carbon products and suggests the exploration of metal–metal oxide interfaces as a promising strategy for further progress.

Since the dawn of agitated brewing in the Paleolithic era, effective mixing has enabled efficient reactions. Emerging catalytic chemical polyolefin recycling processes present unique challenges, considering that the polymer melt has a viscosity three orders of magnitude higher than that of honey. The lack of protocols to achieve effective mixing may have resulted in suboptimal catalyst effectiveness. In this study, we have tackled the hydrogenolysis of commercial-grade high-density polyethylene and polypropylene to show how different stirring strategies can create differences of up to 85% and 40% in catalyst effectiveness and selectivity, respectively. The reaction develops near the H₂–melt interface, with the extension of the interface and access to catalyst particles the main performance drivers. Leveraging computational fluid dynamics simulations, we have identified a power number of 15,000–40,000 to maximize the catalyst effectiveness factor and optimize stirring parameters. This temperature- and pressure-independent model holds across a viscosity range of 1–1,000 Pa s. Temperature gradients may quickly become relevant for reactor scale-up.