The europium catalyst refers to a metal europium, a europium salt or a europium complex having a catalytic function. Europium is a silver-gray solid and belongs to one of rare earth metals. It is the least dense, softest and most volatile element of rare earth elements. It is mainly found in monazite and bastnasite. Europium is the most active metal in rare earth elements. At room temperature, it immediately loses its metallic luster in the air and is quickly oxidized into a powder. Europium reacts violently with cold water to form hydrogen. It also can react with boron, carbon, sulfur, phosphorus, hydrogen, nitrogen, and the like. The common valence of europium has +2 and +3. Europium oxides and nitrates all have certain catalytic functions and are often used as catalysts.

Figure 1. Europium nitrate catalyst

Applications:

The europium catalyst has the characteristics of non-toxicity in the ultraviolet region, high self-stability, and strong absorption capacity, and has high-efficiency photodegradability for organic pollutants. Because europium catalysts exhibit good catalytic effects in photocatalytic reactions, they have many applications in the field of environmental protection.

• Environmental protection: Photocatalysis is the purification of contaminants by the redox ability of a photocatalyst under ultraviolet irradiation. As an efficient and safe environment-friendly purification technology, photocatalytic technology plays an important role in the field of environmental protection. The 4f orbital of the trivalent ion (Eu³⁺) of europium can interact with various organic substances (such as methanol, acetone and acetaldehyde) to form a lewis acid-base complex. The incorporation of the trivalent europium compound into the photocatalyst matrix can promote the adsorption of organic pollutants on the surface of the catalyst and significantly improve the degradation efficiency of the organic pollutants. Therefore, the europium catalyst can be combined with other materials having photocatalytic performance to form a combined photocatalyst. Some trivalent europium compounds (such as cerium nitrate and cerium oxide) are often used as photocatalysts in environmental protection. The europium nitrate doped mesoporous TiO₂ composite photocatalyst has a good degradation effect on organic reagents and is often used for the elimination of acetaldehyde and acetone. The graphene oxide/europium oxide composite catalyst can be used for the degradation of organic dyes such as rhodamine B.

References

1. Shen, Jianyi. (1995). "In situ Moessbauer spectroscopic study of hydrogen reduction of supported europium catalysts." Wuji Huaxue Xuebao 11(4), 429-33.
2. Wang, Xiuzhi. (1993). "Moessbauer spectroscopic study of iron-europium catalysts for F-T synthesis." Fenzi Cuihua (1993), 7(3), 186-92.
3. Huang, Zhier. (1992). "New iron-europium catalyst for the synthesis of liquid hydrocarbon fuel by carbon monoxide hydrogenation." Cuihua Xuebao 13(4), 245-9.