Environmental remediation and sustainable energy generation via photocatalytic technology using rare earth metals modified g-C3N4: A review

Recently, graphitic carbon nitride (g-C3N4) photocatalyst has been comprehensively explored because of its exceptional physio-chemical properties and multifunctional applications in the field of photocatalysis, including water splitting, environmental remediation, CO2 photoreduction, and so on. Nevertheless, the photocatalytic activity of g-C3N4 activity is often hampered by limited light absorption, rapid recombination of photogenerated carriers, and low specific surface area which constrains its large-scale applications. To overcome these drawbacks, several strategies including doping and composite formation have been proposed. Because of their unfilled 4 f orbital that serve as capturing centers to restrict the recombination of photogenerated charges, rare earth elements with higher earth abundance compared to noble metals became affordable and efficient alternatives. Thus, using rare earth elements to alter other photocatalysts is a smart move. This review can give useful information regarding the depth of understanding of the diverse role of rare earth elements in enhancing the photocatalytic activity of g-C3N4. In the first section, the distinctive features of the rare earth metal are emphasized. In the second part, the unique properties of g-C3N4 were discussed in more detail and compared to the conventional photocatalysts. In the last section, the review tries to cover the most recent advancements, especially in the area of rare earth elements-modified g-C3N4 for degradation of persistent organic pollutants as well as in the removal of antibiotics and pharmaceuticals, hydrogen production, and CO2 reduction. Finally, the recent progress in these aspects has been reviewed, as well as difficulties and potential prospects.