设计用于可见光CO2还原的稳定且有效的催化剂仍然具有挑战性。这里,基于Er3的特殊作用和Zn2GeO4/g-C3N4异质结在光催化还原CO2中的特殊优势,成功构建了Er3单原子复合光催化剂。尤其是,原位合成得到的Zn2GeO4:Er3+/g-C3N4不仅更有利于Zn2GeO4与g-C3N4的紧密连接,而且更有利于g-C3N4锚定稀土原子。在可见光照射下,与光催化反应体系中没有任何牺牲剂的纯g-C3N4相比,Zn2GeO4:Er3/g-C3N4的催化效率提高了五倍以上。一系列理论和实验结果表明,Er附近的电荷密度,Ge,Zn,与Zn2GeO4:Er3+相比,O增加,而C周围的电荷密度与g-C3N4相比降低。这些结果表明,提供了一种有效的电子转移方式来促进电荷分离,充分利用了Er3+单原子和4f能级作为电子传输桥的CO2分子活化双重功能。单原子催化和异质结相结合的模式开辟了提高光催化活性的新方法。
It is still challenging to design a stable and efficient catalyst for visible-light CO2 reduction. Here, Er3+ single atom composite photocatalysts are successfully constructed based on both the special role of Er3+ and the special advantages of Zn2 GeO4 /g-C3 N4 heterojunction in the photocatalysis reduction of CO2 . Especially, Zn2 GeO4 :Er3+ /g-C3 N4 obtained by in situ synthesis is not only more conducive to the tight junction of Zn2 GeO4 and g-C3 N4 , but also more favorable for g-C3 N4 to anchor rare-earth atoms. Under visible-light irradiation, Zn2 GeO4 :Er3+ /g-C3 N4 shows more than five times enhancement in the catalytic efficiency compared to that of pure g-C3 N4 without any sacrificial agent in the photocatalytic reaction system. A series of theoretical and experimental results show that the charge density around Er, Ge, Zn, and O increases compared with Zn2 GeO4 :Er3+ , while the charge density around C decreases compared with g-C3 N4 . These results show that an efficient way of electron transfer is provided to promote charge separation, and the dual functions of CO2 molecular activation of Er3+ single atom and 4f levels as electron transport bridge are fully exploited. The pattern of combining single-atom catalysis and heterojunction opens up new methods for enhancing photocatalytic activity.