Life Cycle Assessment of a Chamotte–Nickel Oxygen Carrier: Environmental Hotspot Identification in Oxygen-Carrier Synthesis

Oxygen carriers (OCs) are essential materials in chemical looping technologies for low-carbon hydrogen production; however, the environmental implications of their synthesis remain insufficiently explored. This study presents a gate-to-gate life cycle assessment (LCA) of a chamotte–nickel OC produced via wet impregnation, following ISO 14040/44 guidelines. The functional unit was defined as 1 kg of oxygen carrier (OC), with input material requirements including chamotte, nickel nitrate, and water, as part of the synthesis process. Environmental impacts were modelled using ReCiPe 2016 Midpoint (H). Environmental hotspots varied across impact categories, with wet impregnation and energy-intensive thermal processes showing substantial contributions, while transportation-related burdens were relevant in selected toxicity and resource-related categories. Wet impregnation contributed 38.93% to climate change, approximately 55.6% to ozone depletion, and approximately 95.6% to terrestrial acidification in the modelled inventory. Thermal treatments also contributed substantially to several impact categories, primarily because of their high electricity requirements. Hotspot analysis identified precursor selection, energy supply, and logistics as key drivers of environmental burdens. Qualitative mitigation options include precursor substitution, renewable-energy integration, energy-efficiency improvements, and industrial symbiosis; however, these alternatives were not quantitatively evaluated in the present LCA. These results offer actionable guidance for sustainable OC design and highlight the importance of integrating LCA into early-stage oxygen-carrier design to reduce the environmental burdens associated with material synthesis. Further assessment incorporating OC performance, lifetime, regeneration, and hydrogen yield would be required to determine the implications of these material-level improvements for the environmental performance of hydrogen production.