Louis Fradette

The direct synthesis of dimethyl carbonate (DMC) from methanol and CO₂ requires the use of a dehydrating agent such as 2-cyanopyridine (2-CP) to overcome thermodynamic limitations, alongside controlled catalyst surfaces to limit competing side reactions. In this study, mesostructured CeO₂ catalysts were synthesized via a nanocasting approach using SBA-15 as a hard template. The specific impact of the precursor infiltration method and the final thermal treatment on catalytic performance were evaluated. While a one-step precursor infiltration route yielded the most ordered mesostructure after template removal, the final calcination step emerged as the dominant variable governing catalyst activity and selectivity. Textural analysis confirmed that calcination preserved the interconnected nanorod morphology with only a minor decrease in specific surface area. Temperature-programmed desorption (TPD) revealed that the thermal treatment induced a redistribution of surface acid-base sites, specifically increasing the ratio of medium-strength basic to acidic sites. In situ DRIFTS demonstrated that this tailored surface chemistry facilitated CO₂ activation, promoted the formation of bidentate carbonates, and favored the monomethyl carbonate (MMC) intermediate formation. Consequently, the calcined CeO₂-OS catalyst achieved 74% methanol conversion and 91% DMC yield at 120 °C and 5 MPa, outperforming its uncalcined counterpart by suppressing 2-CP-related secondary reactions.

Rapidly eliminating carbon emissions to the atmosphere to stabilize the Earth’s temperature challenges the retrieval of critical minerals in a responsible way. This work introduces a methodology to consider technological switches in mineral processing pathways as they will come online in the future and supports the prospective analysis of their impacts. Examined technological switches span seven categories: 1) next-generation mineral processing pathways; 2) novel chemical production processes; 3) feedstock substitution for fuels and reductants; 4) reagent substitution; 5) circularity of industrial by-products; 6) valorization of tailings and other waste; and 7) improved water and emissions management practices. Process models of technological switches — sourced from process simulations and company data — are linked to our reconstructed granular inventories of mineral processing pathways. We illustrate our method with a case study on climate impacts, human carcinogenic toxicity and water consumption of three cathode active material (CAM) chemistries; nickel-manganese-cobalt in a 90%, 5% and 5% stoichiometric ratio (NMC955), lithium iron phosphate (LFP) and a nickel-rich (30%) sodium-ion variant (NMMT). By projecting improvements in nickel sulfate and iron phosphate processing pathways, we demonstrate absolute reductions of 16-86% in climate impacts (GWP100), 43-99.8% in human carcinogenic toxicity (HTP-c) and 19-63% in water consumption (WCP) by 2060; where long adoption periods for emerging technologies shrink cumulative reductions to 6% / 4% / 9% in GWP100, 57% / 55% / 24% in HTP-c and 10% / 0% / 29% in WCP between 2025-2060 for NMC955 hydroxide, NMMT and LFP CAM respectively. Cumulative reductions stand much lower than predictions from the prevailing premise tool (REMIND SSP2-PkBudg1150) for climate impacts of NMC955 hydroxide (-39%) and NMMT (-27%). In fact, projected impacts in premise are systematically lower for both climate and human toxicity (carcinogenic) across all CAM chemistries between 2025-2040. Our proposed conceptual framework prevents over-optimistic modeling while retaining the required level of granularity in order to provide action-specific guidance to reduce environmental impacts of mineral processing pathways. We recommend its implementation within existing and emerging prospective tools and its application to a wider set of mineral-intensive ecosystems, such as the solar and wind industries. The online version contains supplementary material available at 10.1007/s11367-026-02658-5.

A safe operating space (SOS) for human activities was proposed to safeguard the Earth system’s resilience. However, translating such SOS into actionable targets remains challenging. The goal of our work is twofold: (1) introduce a methodology for the derivation of SOS-based targets for mobility and electric vehicle batteries; (2) demonstrate target sensitivity to downscaling assumptions and parameters. We derive climate impact and freshwater use targets for mobility and batteries in Germany and Canada in 2030, 2035, and 2050. Target distributions range from 1 to 47 kg CO₂-eq/kWh and 0.1–2.0 m³ water/kWh in 2030, and shrink to 0.4–12 kg CO₂-eq/kWh and 0.1–1.1 m³ water/kWh in 2050 across location and battery sizes. We discuss challenges in deriving sustainability targets and compare them with existing regulatory and company-level product targets, with the perspective of operationalizing SOS-based pathways for mobility.

The process for producing dimethyl carbonate (DMC) from carbon dioxide (CO ₂ ) and methanol is explored in this article. It provides an overview of the thermodynamics involved in DMC synthesis, discussing the challenges and potential solutions. The article highlights the reported use of catalysts and dehydrating agents to improve DMC yield and selectivity. Thermodynamic analysis shows that the reaction is strongly limited thermodynamically over a large range of operating conditions, both in the gaseous and liquid phases. The various methods proposed in literature to circumvent this limitation are discussed and those with realistic potential for large scale implementation are identified and compared.

This work introduces a simple, efficient, and reliable approach for producing acoustic porous materials by using solid-stabilized emulsion templates. The technique allows for precise control of the pore size through straightforward emulsification processing conditions, highlighting its potential for developing multifunctional acoustic foams. The microstructure of the porous material was investigated using X-ray microtomography and open pore network modeling. The correlation between processing conditions, porous microstructure, and acoustic performance was determined. The findings reveal that the desired sound absorption performance can be achieved by adjusting the rotational speed during emulsification, which affects droplet size and ultimately results in targeted pore size, connectivity, and tortuosity. Notably, a near perfect sound absorption coefficient at 1100 Hz was achieved for samples with largest pores, highest porosity, and greatest connectivity. Furthermore, samples with medium porosity and pore size, but the highest tortuosity, exhibited maximum sound absorption below 500 Hz, despite a thickness of only 3 cm. This performance is particularly notable, as it is challenging to achieve with conventional acoustic foams, demonstrating the potential of this novel approach for developing high-performance acoustic materials over broad ranges of frequencies.

Batteries are essential to transition to a fossil-free energy system, but only if coherently planned will their manufacturing generate minimal environmental impacts. Aggregated life cycle inventories for battery-grade nickel prevent life cycle analysts from easily pinpointing key impact contributors. The present work reconstructs inventories via disaggregation of current and emerging processing routes. Improving process granularity demonstrates variability in climate impacts of 74 kgCO_2eq/kWh for nickel sourcing of an NMC-811 cell. Furthermore, the global ecoinvent v.3.9.1 dataset for nickel sulfate could gravely underestimate climate impacts by 120 kgCO_2eq/kg Ni equivalent. Major contributors to climate impacts are readily identified for six nickel processing pathways, spanning two mineral families – laterite and sulfide – and three main processing routes – hydrometallurgy, bioleaching and pyrometallurgy. A preliminary assessment of all impact categories highlights the need for both improved fate models and data collection on inventory parts such as tailings management which are often neglected in carbon-focused studies.