Recent progress in the development of synthetic oxygen carriers for chemical looping combustion applications

Continuously rising concentrations of CO2 in the atmosphere has led to significant negative impacts on the environment which propelled research efforts to replace fossil fuel-based energy with clean energy sources. However, the reliance on fossil fuel as the main energy source is projected to stay for many years to come, and therefore developing cleaner pathways to utilize fossil fuels for energy generation is paramount. Chemical looping combustion (CLC) has emerged in recent years as a promising technology for CO2 capture in power plants and other CO2 intensive industries. A key cornerstone for CLC is the development of efficient oxygen carriers with high oxygen capacity, fast kinetics, cyclic stability, mechanical strength, and low cost. The research progress in this field is rapidly growing to tackle the major materials and operational challenges to advance the knowledge toward a commercial scale CLC application. This work provides an overview of the significant ad-vancements achieved over the past seven years in the development of synthetic metal oxide-based oxygen car-riers. A summary of key performance indicators used to evaluate oxygen carriers is presented in this study to enable for a systematic assessment of the oxygen carriers' properties and performance. This work is focused on summarizing and critically reviewing the literature on the development of oxygen carriers such as Ni, Cu, Fe, Mn, Co-based metal oxides and combined/mixed oxygen carriers in the past seven years. Studies of naturally occurring materials and waste materials used as oxygen carriers are excluded from this review which is mainly focused on synthetically prepared materials. Significant efforts were dedicated to investigating the role of the supports, synthesis methods, promotors, and other factors affecting the CLC performance of synthetic oxygen carriers using solid, liquid, and gaseous fuels. This review also outlines the main challenges, research needs and opportunities for future progress to highlight potential pathways to develop synthetic oxygen carriers in an environmentally friendly, and cost-effective manner.

Automated summary

Continuing increase in atmospheric CO2 concentrations has had significant negative impacts on the environment, prompting research efforts to find alternative energy sources to replace fossil fuels. Chemical looping combustion (CLC) has emerged as a promising technology for CO2 capture, and the development of efficient oxygen carriers is crucial for its success. This work provides a comprehensive overview of the advancements in synthetic metal oxide-based oxygen carriers over the past seven years, along with key performance indicators used for evaluation. The review focuses on the development of oxygen carriers such as Ni, Cu, Fe, Mn, Co-based metal oxides, and outlines the challenges, research needs, and opportunities for future progress in this field.