Among various forms of sulfur, some organosulfur compounds (particularly alkyl thiophenes) in biomass are rather refractory under hydrothermal conditions, posing a threat to the catalysts used in catalytic hydrothermal gasification (cHTG). In petrochemistry, alkyl thiophenes are usually treated by oxidative desulfurization (ODS) under mild conditions and removed in the form of sulfones, generating a sulfur-free product stream. ODS could be used to oxidize organosulfur compounds to sulfate, allowing efficient separation by exploiting the low salt solubility in supercritical water. To assess the viability of ODS in a cHTG process, we explored the effect of temperature and oxidant concentration (O/S ratio) on sulfate production from the ODS of thiophene. More importantly, the impact of Mo- and W-based carbon materials on the conversion of thiophene to sulfate was investigated. Our results showed a sulfate yield below 5% at temperatures ranging from 50 °C to as high as 400 °C in pressurized water. Experiments varying the oxidant-to-sulfur (O/S) ratio revealed that lower ratios (≤12) enhanced both sulfate yield and oxygen selectivity, whereas higher ratios (58 and 116) led to decreased selectivity due to excess oxidant consumption by organic matter. Carbon nanofibers (CNFs) alone increased the sulfate yield threefold (to 2.3%) at 400 °C, an effect attributed to oxygen-containing surface groups. Acid treatment of CNFs further boosted this yield to 7%. A clear correlation between surface functionalities and catalytic activity was established using FTIR and Boehm titration. Among metal oxides, Mo(iv), in the form of MoO2, was identified as an active phase for oxidative desulfurization (ODS), achieving a sulfate yield of 12%, while MoO3 and WO3 showed no such activity. However, metal oxide loading altered the CNF surface properties, potentially diminishing their promotional effect. These findings provide a basis for further development of MoO2 catalysts supported on surface-modified carbon materials, with the goal of preserving beneficial carbon surface characteristics.

A novel sustainable synthesis strategy for producing a range of structurally distinct zeolites, specifically Zeolite 4A, Zeolite 13X, and Zeolite Y, is presented. This method avoids organic templates (commonly used for many high-silica zeolites such as ZSM-5, Beta, or high-silica Y) and directly produces Zeolite 4A, Zeolite 13X, and Zeolite Y from natural bentonite clay without the need for synthetic silica or alumina sources and thus offers a much more environmentally-benign production strategy than existing commercial synthetic routes. By systematically tuning alkaline fusion conditions and hydrothermal crystallization parameters, selective zeolite phase formation is achieved: lower fusion temperatures and NaOH/clay ratios favor the formation of LTA-type Zeolite 4A, while higher values promote the formation of FAU-type Zeolite 13X and Zeolite Y. The synthesized zeolites demonstrated structural characteristics and adsorption performance comparable to their commercial counterparts. Zeolite 13X exhibited the highest CO2 adsorption capacity, attributed to its elevated microporosity and sodium content, while Zeolite Y showed enhanced hydrothermal stability and reduced water affinity, resulting from its higher Si/Al ratio and lower cation density. Water vapor adsorption isotherms and repeated cycling tests revealed clear differences in hydrothermal stability between the synthesized zeolites. A cradle-to-gate life cycle assessment (LCA), performed for Zeolite 13X as a representative product, revealed a ∼90% reduction in global warming potential (2.48 vs. 24.25 kg CO2 eq. per kg), over 95% lower cumulative energy demand, and significantly decreased ecotoxicity and human toxicity indicators when compared to conventional chemical synthesis. Additionally, cost-oriented economic analysis showed that the clay-based synthesis route reduces the production cost of Zeolite 13X by approximately 33% compared to conventional chemical synthesis. Overall, this work provides a mechanistically informed, environmentally friendly framework for the phase-selective synthesis of industrially relevant zeolites from natural clay.

Understanding reactive mass transport in redox flow reactors is key to improving performance, yet conventional characterization techniques often rely on cell-averaged metrics and fail to resolve local transport phenomena. In this study, we employ operando neutron radiography to visualize concentration distributions in redox flow cells with non-aqueous electrolytes, leveraging the high attenuation of hydrogen-containing organic molecules and boron-containing supporting ions. Symmetric flow cell experiments were conducted with three electrode types (paper, cloth, and a hierarchical porous electrode fabricated by non-solvent induced phase separation), and two flow field designs (parallel and interdigitated). We find that for kinetically facile electrolytes with low ionic conductivity and with parallel flow fields, electrodes with large pores in the though-plane direction (i.e., carbon cloth) augment the current output. Additionally, interdigitated flow fields sustain higher currents than parallel flow fields at a fixed potential and flow rate due to enhanced convective transport. Despite significant differences in macroscopic performance among the studied materials, the concentration profiles within the cell showed only minor variations within the studied operating conditions and imaging configuration. The cloth electrode and interdigitated flow field exhibited slightly more uniform concentration profiles across the electrode thickness compared to the paper electrode with the parallel flow field. In contrast, the phase-separation electrode displayed more steep concentration profiles and a stronger dependency on polarity reversal. Neutron radiography further uncovered critical secondary effects, including salt precipitation and flow field underutilization. These findings highlight the potential of operando imaging to inform the design and operation of electrochemical reactors for a range of technologies.

The formation of metallic dendrites during battery cycling is a persistent challenge for alkali metal-ion batteries, reducing cycle life and posing safety risks. Although surface defects are often implicated in inhomogeneous metal nucleation, the atomic-scale mechanisms by which they promote metal clustering and subsequent dendrite formation remain poorly understood. Here, we use first-principles calculations to investigate how carbon monovacancies (VC) influence the clustering behaviour of alkali metals (Li, Na, and K) on graphene – a common basal-plane motif in graphite, hard carbons, and graphene-based anodes. Clusters of Li, Na, and K of varying size (Mn for n ∈ {1–12}) are characterised on pristine and defective graphene to understand their stability. On pristine graphene, cluster formation is hindered for Li due to the instability of small clusters (n ≤ 3) and significant Li–Li repulsion, and suppressed for K due to weak K–K binding and its larger ionic radius. In contrast, Na exhibits spontaneous clustering, suggesting a higher propensity for dendrite formation even in the absence of defects. The introduction of a VC dramatically alters these trends: it stabilises small (n ≤ 3) clusters across all three metals by enhancing binding strength with the surface and modifying charge localisation. For Li, the vacancy overcomes the barrier to early-stage nucleation; for Na, it promotes growth at even lower metal loadings; and for K, clustering becomes locally favoured albeit only for the smallest cluster sizes (n ≤ 3). These results clarify the defect-facilitated pathways to metal clustering, offering atomistic insight that can inform the development of more dendrite-resistant carbon architectures.

Intermetallic compounds hold great potential owing to the possibility of fine tuning their structure- and composition-dependent catalytic properties. Herein, a series of intermetallic Pt–Zn nanoparticles decorated on a TiO2 support was designed via a novel and facile direct vapour–solid synthesis approach, and their co-catalytic performance towards the light-driven hydrogen evolution reaction (HER) was investigated. The intrinsic activity of Pt/TiO2 was almost doubled via the addition of Zn and the formation of Pt27–Zn73/TiO2, achieving a substantial increase in the apparent quantum yield (AQY) values up to 10.3%. In contrast to Pt–Zn intermetallic co-catalysts generally exhibiting higher HER rates, the interaction of Zn with surface defects of TiO2 enhanced the catalyst stability, resulting in strongly suppressed deactivation. This work introduces intermetallic cocatalysts as promising systems, highlighting the influence of composition and structure on catalyst activity and providing future research directions.

Lead zirconate titanate (PZT) is one of the most widely used piezoelectric materials due to its excellent performance. However, its lead content raises serious environmental and health concerns, prompting the search for more sustainable alternatives. In this work, we explore whether a lead-free composite based on the halide perovskite FASnI3 embedded in a polyvinylidene fluoride (PVDF) matrix could serve as a viable substitute for PZT in piezoelectric energy harvesting applications. To assess this potential, we conduct a comparative life cycle assessment (LCA) of both materials in thin-film device configurations, following a cradle-to-grave approach. The analysis includes the environmental impacts of raw material extraction, manufacturing, potential energy recovery during use, end-of-life treatments, and accidental release scenarios. The results show that PZT-based devices have consistently higher environmental impacts across all life cycle stages, mainly due to the high energy requirements for their synthesis and thin-film deposition, as well as the use of lead. In contrast, the FASnI3–PVDF composite benefits from low-temperature processing and the absence of lead, resulting in significantly lower impacts during manufacturing and the use phase. This study offers a first comparative insight into the environmental trade-offs of substituting PZT with halide perovskite-based composites, contributing to the identification of more sustainable piezoelectric solutions.

Correction for “Vacancy enhanced Li, Na, and K clustering on graphene” by Jonathon Cottom et al., Sustainable Energy Fuels, 2025, 9, 2813–2826, https://doi.org/10.1039/D5SE00130G.

A series of novel porous hydrogen-generation materials with the formulae Al–(BiO)2CO3, Al–4BiNO3(OH)2·BiO(OH), and Al–Bi2(SO4)3 were synthesized by ball milling and spark plasma sintering (SPS).

Schematic representation of light-induced processes in artificial photosinthetic systems composed by multinuclear metal complexes.

The recycling of spent lithium-ion batteries (LIBs) is crucial to sustainably manage resources and protect the environment as the use of portable electronics and electric vehicles (EVs) increases. However, the safe recycling of spent LIBs is challenging, as they often contain residual energy. Left untreated, this can trigger a thermal runaway and result in disasters during the recycling process. For efficient recycling, it is important to withdraw any leftover energy from LIBs, regardless of the processing method that follows the discharge. The electrochemical discharge method is a quick and inexpensive method to eliminate this hazard. This method works by immersing batteries in an aqueous inorganic salt solution to discharge LIBs completely and efficiently. Previously, research focus has been on different inorganic salt solutions that release toxic or flammable gaseous products during discharge. In contrast, we present an entirely new approach for electrochemical discharge - the utilization of an Fe(ii)-Fe(iii) redox couple electrolyte. We show that this medium can be used for efficient LIB deep discharge to a voltage of 2.0 V after rebound, a level that is low enough for safe discharge. To accomplish this, periodic discharge methods were used. In addition, no corrosion on the battery casing was observed. The pH behavior at the poles was also investigated, and it was found that without convection, gas evolution during discharge cannot be avoided. Finally, it was discovered that the battery casing material plays a vital role in electrochemical discharge, and its industrial standardization would facilitate efficient recycling.