Roland C. Turnell-Ritson

Layered double hydroxides (LDHs) have been demonstrated as high-activity electrocatalysts for the oxygen evolution reaction (OER), but their performance can be limited by their relatively low electrical conductivity.

Accumulation of atmospheric carbon dioxide demands innovations in sorbent technologies capable of direct CO2 removal from ambient air. Herein, we report the aqueous miscible organic solvent treatment (AMOST) of borate-intercalated layered double hydroxides (LDHs), forming highly exfoliated Mg3Al-LDH nanosheets, and evaluate them as high surface area supports for polyethyleneimine (PEI)-based direct air capture (DAC). Compared with carbonate-intercalated Mg3Al-LDH, the borate-intercalated analogue undergoes substantially greater AMOST-induced exfoliation, producing predominantly mono-/few-layer nanosheets with a very high specific surface area of 762 m2 g–1 and a total pore volume of 3.02 cm3 g–1. The high surface area and porosity allow incorporation using a nominal PEI loading of 67 wt %, enabling direct comparison of the carbonate- and borate-derived support architectures. Under humid breakthrough conditions at 400 ppm CO2/N2 and 25 °C, the borate-derived PEI-Mg3Al-LDH composite can achieve a high CO2 uptake of 2.90 mmol g–1, reaching 78% capacity in 20 min, demonstrating fast sorption kinetics. The sorbent also exhibits 96 % capacity retention after 20 adsorption–desorption cycles – competitive with reported PEI-supported solid amine sorbents measured under comparable dry DAC conditions. These results establish borate-assisted LDH exfoliation as a promising strategy for preparing high surface area supports for solid amine DAC sorbents.

AMOST of borate-intercalated layered double hydroxides (LDHs) generates predominantly mono-/few-layer nanosheets that retain exceptionally high N ₂ BET-derived surface areas and pore volumes following isolation as dry powders.

The thermal catalytic hydrogenolysis of polyolefins offers a pathway to convert plastic waste to value-added hydrocarbons. However, the reliance on noble metals such as Ru or Pt remains a significant barrier to large-scale implementation. In this work, we demonstrate that the Zr-containing mixed metal oxides (MMOs), Co0.7Al0.3–xZrx (CAZ), Ni0.7Al0.3–xZrx (NAZ), and Ni0.7Co0.3–xZrx (NCZ), with x = 0, 0.1, 0.2, and 0.3, are highly effective at 250 °C under 20 bar of H2 for virgin isotactic polypropylene (PP) (Mw = 240 kDa) hydrogenolysis to give liquid hydrocarbon products. The catalysts were produced by calcination of the Zr-containing layered double hydroxide (LDH) precursors; [Co0.7Al0.3–xZrx(OH)2][CO3](0.3–x)/2, [Ni0.7Al0.3–xZrx(OH)2][CO3](0.3–x)/2, [Ni0.7Co0.3–xZrx(OH)2][CO3](0.3–x)/2; x = 0, 0.1, 0.2, and 0.3. This approach allowed us to exploit the compositional tunability of the LDH framework to control the homogeneous distribution of the active metal centers. We find that Zr incorporation in these MMOs can significantly enhance catalytic PP hydrogenolysis. Our best-performing catalysts, Co2.1Al0.3Zr0.6Oy, delivers, after 1 h at 275 °C and 20 bar of H2, liquid hydrocarbon yields above 75% at a total PP conversion of over 90%, while keeping methane yields below 3%. Mechanistic studies show that these catalysts favor backbone C–C cleavage, delivering C3, C6, and C9 hydrocarbon selectivity. These scalable, highly efficient, and cost-effective catalysts are also efficient for the hydrogenolysis of a mix of commercial PP products. Hydrogenolysis of mixed pipette tips using Co2.1Al0.3Zr0.6Oy (275 °C, 1.5 h, 20 bar H2) produced a liquid hydrocarbon yield of 74%.

Realizing net-zero emissions demands the design of innovative and efficient catalysts for CO2 valorization. Herein, we report a core@shell-structured catalyst precursor, h-ZrO2@Cu1.3ZnAl1.6-LDH, in which layered double hydroxide (LDH) platelets are arranged around hollow zirconia spheres (h-ZrO2), maximizing the interfacial area between the active LDH component and zirconia promoter. The h-ZrO2@Cu1.3ZnAl1.6-LDH-derived catalyst efficiently converts CO2 into methanol, reaching space-time yields (STYs) comparable to commercial catalysts, despite a 54% reduction in Cu loading (0.59 gMeOH gcat−1 h−1 at 250 °C, 45 bar, H2/CO2 = 3, 18,000 mL g−1 h−1 weight hourly space velocity, WHSV). Reporting the STY on a per gram copper basis highlights the efficiency of the catalyst: h-ZrO2@Cu1.3ZnAl1.6-LDH is twofold more active than the commercial catalyst under the same conditions (2.7 vs 1.3 gMeOH gcat−1 h−1).

In recent years, catalytic hydrocracking has emerged as a promising waste‐to‐feedstock solution for processing plastic waste. Although ruthenium nanoparticle catalysts exhibit high activity in converting polyolefins into small alkanes, they also tend to produce undesirable methane (CH ₄ ) via terminal C─C bond hydrogenolysis. Herein, we report a Ru‐supported sulfated zirconia (RuSZ ₁ ) catalyst for the efficient isomerization and hydrocracking of polyolefins without generating CH ₄ . Various high‐M _w polyethylene and polypropylene samples (up to 1 000 000 g/mol) were fully converted into branched alkanes (C ₄ ‐C ₂₀ ). Control experiments using RuSZ ₁ revealed negligible scission activity for alkanes with fewer than seven carbons, suggesting that isomerization precedes hydrocracking. Hydrogenolysis to form C ₁ and C ₂ products is likely inhibited by saturation of sulfate species at the Ru sites, and these products were not observed under any reaction conditions. Full conversion of polyolefins under solvent‐free conditions was achieved, with up to 93% yield of C ₃ ‐C ₁₂ alkanes.

Polymer–solvent interactions influence polypropylene chain conformation and catalytic performance. Among the solvents tested, methylcyclohexane enhances polypropylene conversion, favouring naphtha-range liquids over gaseous products.

A green, scalable and cost-effective synthesis of microspherical Mg/Al–CO₃ LDHs with an average particle size of 34 ± 6 μm and a multi-hierarchical morphology.

Single‐atom catalysts (SACs) present a promising subclass of classic heterogeneous catalysts by maximizing metal dispersion and enhancing efficiency. Although high‐density SACs (HD‐SACs) are reported, their synthesis is typically constrained to specific metal‐support combinations and high‐temperature annealing, limiting their translation to wider applications. Herein, a universal bottom‐up approach for the preparation of mono‐ and bimetallic HD‐SACs based on the polycondensation of 1,2,4,5‐benzenetetramine with a wide range of metal monomers containing 1,10‐phenanthroline‐5,6‐dione ligands is introduced. The synthesized materials are atomically dispersed and exhibit metal loadings up to 27.5 wt% with high structural stability. Their versatility as catalysts is explored in electrocatalytic and photocatalytic applications. The materials exhibit remarkable stability under operational conditions. Furthermore, this synthetic strategy is scaled up and automated, demonstrating the robustness and reproducibility and laying the groundwork for self‐optimizing data‐driven materials discovery.

Polyurethane is a versatile plastic finding applications across diverse sectors ranging from construction to household products. Recently, there is growing interest in the chemical recycling of polyurethane via catalytic hydrogenation to recover anilines and polyols. However, examples of heterogeneous catalysts are lacking despite their practicality for scale-up to a commercially relevant level. Herein, the conversion of model carbamate compounds is investigated using different metal-oxide catalysts, with CeO₂ exhibiting the best activity and achieving the highest yield of aniline products (up to 100% conversion and 92% yield of anilines). A volcanic correlation is found between the acidity of the metal-oxide catalysts and their activity in cleaving the carbamate bond. The high activity of CeO₂ may be primarily attributed to a low oxygen vacancy formation energy and highly redox active Ce³⁺/Ce⁴⁺ pairs. Based on control reactions under different conditions and in situ NMR studies, a mechanism for carbamate bond dissociation on CeO₂ was proposed. Notably, both solvent-free hydrogenation and hydrogen-free transfer hydrogenation approaches may be utilized to depolymerize various commonly encountered polyurethane (thermoplastic and thermoset) products using CeO₂.