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The conversion of methanol — which can be produced from non-fossil resources — to important chemical commodities such as olefins and aromatics allows for the diversification of organic feedstocks beyond petrochemicals. This Review covers recent discoveries about the mechanism of this process and discusses how these link to practical aspects in reaction engineering.

As part of the March Focus issue of Nature Chemical Engineering, we asked 13 leading researchers to spotlight a challenge or opportunity in reaction engineering that they believe holds particular promise for advancing this core area of chemical engineering research and practice.

Bioethanol-based alkylation of benzene is a potentially sustainable route to commodity chemicals, but there is little knowledge of the reaction mechanism. Here, Weckhuysen and co-workers study the zeolite catalysed alkylation of benzene with ethanol, identifying the active alkylating agent and experimentally show the presence of a σ-complex intermediate.

Insight into the active zeolitic domains of catalyst particles used in fluid catalytic cracking is limited by the particles' complex nature, but is crucial to improving these billion dollar catalysts. Now, a staining method allows confocal fluorescence microscopy to probe within single catalyst particles, and correlate Brønsted acidity distributions to catalytic activity.

Characterizing the internal architecture of zeolites is crucial for understanding their structure–function relationships, and for acid–base heterogeneous catalysis. Using a unique combination of diffraction and microscopy techniques provides a unified picture of the morphology of intergrowth structures and confirmation of surface barriers for molecular diffusion.

Catalytic cracking is an emerging technology allowing to convert plastic waste into hydrocarbon feedstocks. Here, the authors show that the activity of ultrastable zeolite Y depends on the concentration of acid sites located outside of micropores.

To mark the occasion of Nature Chemistry turning 10 years old, we asked scientists working in different areas of chemistry to tell us what they thought the most exciting, interesting or challenging aspects related to the development of their main field of research will be — here is what they said.

A study of the industrial catalyst titanium silicalite-1 suggests that the conventional view of the structure of its active sites is wrong. The findings might enable further optimization of related industrial catalysts.

The evolution of Pd active centers in size and spatial distribution often leads to irreversible deactivation in many high-temperature catalytic processes. Here the authors demonstrate the use of defective alumina (Al₂O_3-x) as a catalyst support to anchor Pd atoms and suppress the growth of Pd clusters in catalytic methane oxidation.

Zeolite-encaged silver nanoclusters as highly photoluminescent materials.

Lignin is an abundant renewable resource, but its intrinsic recalcitrant nature has so far hampered its conversion into higher value chemicals. Now, a two-step strategy, oxidation followed by bond cleavage, has been shown to deconstruct lignin into high yields of low-molecular-weight aromatics.

This protocol describes how to perform nanoscale chemical imaging using tip-enhanced Raman spectroscopy (TERS). The procedure details the preparation of plasmonically active TERS probes, alignment of a TERS system, and various example procedures.

Dual-wavelength tip-enhanced Raman spectroscopy can be used to monitor photocatalytic reactions at the nanoscale.

Chemists are like detectives: they like to know 'whodunit' during a catalytic reaction. Combining advanced electron microscopy with intelligent molecular design has now provided strong evidence for the presence of a highly active site within a complex catalytic solid.

Bismuth is a promising catalyst for formic acid production from CO₂ electroreduction, but its active site and phase under operation remain elusive. Now, a series of bismuth oxyhalide nanoplatelets has been evaluated using in situ techniques during the electrochemical CO₂ reduction reaction, revealing insights about the active bismuth phase.

Probing gas sorption on defects and facets of porous materials at the nanoscale is challenging. Here, we visualize nano-domains of preferred formaldehyde sorption on (defective) ZIF-8 microcrystals using in situ Photo-induced Force Microscopy (PiFM).

To overcome mass transport limitations in zeolite-catalysed reactions, scientists must often resort to hierarchical or nanosized zeolites; however, the synthesis of such materials remains challenging. Here the authors disclose a one-pot method for the preparation of Si-zoned MFI-type catalysts with improved diffusion properties for the methanol-to hydrocarbon reaction.

The performance of catalytic materials is determined by small-scale chemical and structural variations over large volumes. Here the authors report a correlative spectroscopy approach capable of visualizing processes over multiple length scales, and model the effects of poisoning on mass transport.

Substitution of framework silicon for aluminium in zeolites affects Brønsted acidity and subsequently catalytic activity. Here, the authors use atom probe tomography to obtain quantitative insights into the spatial distribution of individual aluminium atoms, including their distribution and segregation.

Catalytic conversion of CO₂ into valuable hydrocarbons is a promising way to mitigate climate change. This work uncovers that cobalt oxide nanoparticles on a titania carrier produce more C₂₊ hydrocarbons than their metallic cobalt counterpart by following a different reaction mechanism.

Metal oxide–zeolite bifunctional catalysts allow coupling of reactions and so enhance catalytic processes, but structure and reactivity control is difficult. Here, a general synthesis is presented for metal oxide–zeolite double-shelled hollow spheres, which outperform other catalysts for petroleum production.

Ziegler-type polyolefin catalysts have proven to be hard to characterize. Here the authors present a model system consisting of patterned LaOCl spherical caps, simulating bulk particles while facilitating the use of micro(-spectro)scopic characterization techniques specifically aimed at surfaces.

Bisphenol A (BPA) is an industrial chemical produced in large quantities for use primarily in the manufacturing of plastics. However, its adverse effects on human health are driving the development of safer and more sustainable alternatives. Now, a synthetic route enables such an alternative, starting from renewable lignin biomass.

Structure insensitivity in catalysis has been empirically observed, but no satisfactory theoretical explanation could be given. By studying different nanoparticle sizes under dynamic catalytic conditions reaction-dependent particle size dependent restructuring was linked to the aforementioned.

The heterogeneity of industrial particulate catalysts is a major obstacle in the study of their deactivation mechanisms. Here, the authors introduce a droplet microreactor capable of sorting fluid catalytic cracking equilibrium catalyst particles in a high-throughput fashion based on their activity.

The accessibility of materials’ porous domains is typically explored through bulk, and often non-visual, measurements. Now, an integrated fluorescence microscopy approach has established a direct visual relationship between pore architecture (which depends on pore sizes and interconnectivity), molecular transport, and in turn catalytic performance in industrial-grade catalyst particles.

Carbon dioxide is a desired feedstock for platform molecules, such as carbon monoxide and higher hydrocarbons, but needs improved catalysts. Here, the authors use a combined theoretical and experimental approach to tune the activity and selectivity of CO₂ conversion over nickel towards desired products.

Understanding structure sensitivity—how the structural morphology of a surface influences a catalytic reaction—is important for rational catalyst design. Here, the synthesis and in-depth characterization of a range of size-defined nickel clusters shows the structure sensitivity of CO₂ hydrogenation, and also identifies two size-dependent reaction pathways.

The hydrogenation of leuvinic acid to γ-valerolactone is an important step in the conversion of lignocellulose to high value chemicals. Here, the authors report that bimetallic alloys are active and stable catalysts for this reaction, and attribute this to geometric and electronic effects.

Cu-exchanged zeolite chabazite has superior stability over other catalysts in automotive NO_x reduction. Here, the authors use atom probe tomography to create 3D nanoscale reconstructions of two Cu-containing zeolite catalysts, providing a complete picture of their deactivation mechanisms during aging.

Bisphenol A (BPA) is an essential building block for manufacturing plastics, but its adverse health effects have become a major concern. Here the authors show a zeolite-catalysed synthetitic route to bio-renewable BPA alternatives that feature excellent safety and preserve efficacy of function.

The rational design and synthesis of dual-atom catalysts with structurally uniform and flexible active sites remains challenging. Now the tailored synthesis of a Janus Fe–Co dual-metal catalyst is reported in which the Fe and Co atoms are coordinated to N and O, respectively, and linked through bridging N and O atoms.

Understanding the fundamentals of a catalytic process remains an intellectual challenge. Now, a method has been developed that can discriminate mass transport phenomena from reaction kinetics at the single-molecule and single-particle levels.

Highly stable and active Pt–Sn sub-nanometre clusters are located in sinusoidal zeolite channels, leading to improved and more stable propane dehydrogenation catalysts.

Multi-modal approaches to simultaneously characterize different aspects of a reaction in situ are not readily accessible. Here, catalyst extrudates equipped with both luminescence thermometry and Raman spectroscopy sensors are introduced, providing an in-depth picture for the conversion of syngas on a supported rhodium catalyst.

Elucidating the reaction mechanism of a catalytic process is very challenging. Now, advanced solid-state nuclear magnetic resonance experiments demonstrate the importance of oxygenates to regulate the conversion of synthesis gas over an oxide–zeolite-based bifunctional catalyst material.

The beauty and activity of enzymes inspire chemists to tailor new and better non-biological catalysts. Now, a study reveals that the active sites within heterogeneous catalysts actively cooperate in a fashion phenomenologically similar to, but mechanistically distinct, from enzymes.

Designing efficient solid-state catalysts would be easier if we knew which parts of them do what. Fluorescence microscopy could help: the technique allows single catalytic events to be observed in real time.

The conversion of natural gas to chemicals and fuels via the Fischer-Tropsch synthesis process, depends on the ability of catalyst materials to suppress the formation of methane and carbon dioxide. Here, the authors develop a Co₁Mn₃-Na₂S catalyst, which has a hydrocarbon product spectrum deviating from the Anderson–Schulz–Flory distribution.

Gas sorption studies in porous materials typically reflect their overall gas uptake. Now, using a ‘gas adsorption crystallography’ method, the gas adsorption isotherms of two metal–organic frameworks (MOFs) have been quantitatively decomposed into sub-isotherms that reflect the pore-filling behaviour of various guests in the different types of pores present in the MOFs.

The Lebedev process is an established approach to convert ethanol into butadiene catalysed by silica–magnesia prepared by the so-called wet-kneading method. However, the role and impact of this wet-kneading approach have not been fully uncovered. Here the authors reveal important aspects of this process and elucidate the role of the different active sites it generates within silica–magnesia.

Nanosized zeolites enable better catalytic performance; however, their synthesis is non-trivial. Here, a simple treatment is presented that enables the growth of nanosized fins on zeolites that act as pseudo-nanoparticles, reducing deactivation rates for methanol-to-hydrocarbon catalysis.

As of yet, no clear structure–performance descriptors have been developed to tune the catalytic activity of zeolitic methanol-to-olefin catalysts. Now it has been shown that introducing Lewis acidity into Brønsted acidic zeolites boosts their performance. Although Brønsted acidity is found to define propylene selectivity, Lewis acidity is responsible for prolonging lifetime.

This Review describes the general trends and implications of heterogeneities within individual catalyst particles as observed by modern spatiotemporal spectroscopy. It discusses how catalytic materials have been found to display heterogeneities in structure, composition and reactivity in space and time. The implications of these findings for future catalyst design are also described.

Efforts to find renewable alternatives to fossil fuels that might enable a carbon-neutral society by 2050 are described, as well as outlining a possible roadmap towards a refinery of the future and evaluating its requirements.