A review on recent applications and future prospects of rare earth oxides in corrosion and thermal barrier coatings, catalysts, tribological, and environmental sectors

Rare earth oxides (REOs) and metals as an important class of materials have generated global interest in modern technology. Here, eight REOs (R2O3, R = Yb, Er, Sm, Eu, Y, Gd, Dy, and Ce) are identified those are mostly used in diverse chemical and industrial sectors. In this concise review the applications of these REOs in corrosion protection, thermal barrier coating, hydrophobic coating, catalytic reactions, refrigeration, photoactivity, environmental, and tribological sector are briefly summarized, which are sparsely documented in the existing literature review. In what follows, recently published relevant literature is systematically evaluated and key insights are addressed. The use of REOs as nonstoichiometric compounds or as doping agents to enhance the system performance of specific applications is commendable. Related lab-scale studies, therefore, will invoke the potential exploitation of individual or blended REOs for large-scale commercialization. However, phase transformation and high energy consumption in the thermal coating, multi-step fabrication of hydrophobic coating, the building of aromatic pollutants in catalysis, magnetic entropy shift in refrigeration, and photo corrosion are some of the inherent hindrances of these oxides. These issues warrant prompt actions from the scientific community to deliver cost-effective, efficient, and environmentally sustainable applications. Regardless, this review is expected to provide critical insights into REOs for contrasting industrial applications and encourage interested researchers to dig deeper in finding the best strategic solutions to counter prevalent challenges.