Kan Dongxiao, Wang Dashuai, Cheng Yingjie, Lian Ruqian, Sun Bo, Chen Kaiyun, Huo Wangtu, Wang Yizhan, Chen Gang, Wei Yingjin
Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), Jilin Engineering Laboratory of New Energy Materials and Technology, College of Physics, Jilin University, Changchun 130012, China.
Advanced Materials Research Central, Northwest Institute for Non-Ferrous Metal Research, Xi'an 710016, China.
ACS Appl Mater Interfaces. 2021 Nov 10;13(44):52508-52518. doi: 10.1021/acsami.1c12893. Epub 2021 Oct 26.
MXenes have been used as substrate materials for single-atom catalysts (SACs) due to their unique two-dimensional (2D) structure, high surface area, and high electronic conductivity. Oxygen is the primary terminating group of MXenes; however, all of the reported Pt SACs till now are fabricated with F-terminated MXenes. According to the first-principles calculations of this work, the failure of using O-terminated MXenes as substrates is due to the low charge density around Pt and C, which weakens the catalytic activity of Pt. By adjusting the electronic structure of MC using a second submetal with a lower work function than M, 18 potential bifunctional Pt SACs are constructed based on O-terminated bimetal MXenes. After further consideration of some important practical application factors such as overpotential, solvation effect, and reaction barriers, only four of them, i.e., CrNbCO-V-Pt, CrTaCO-V-Pt, CrNbCO-V-Pt, and CrTaCO-V-Pt, are screened as bifunctional oxygen reduction reaction/oxygen evolution reaction (ORR/OER) catalysts. All of these screened SACs are originated from Cr-based MXenes, implying the significance of Cr-based MXenes in designing bifunctional Pt SACs.
由于其独特的二维（2D）结构、高表面积和高电子导电性，MXenes已被用作单原子催化剂（SACs）的基底材料。氧是MXenes的主要端基；然而，迄今为止所有报道的铂单原子催化剂都是用氟端基化的MXenes制备的。根据本工作的第一性原理计算，使用氧端基化的MXenes作为基底失败的原因是铂和碳周围的电荷密度低，这削弱了铂的催化活性。通过使用功函数比M低的第二种亚金属来调整MC的电子结构，基于氧端基化的双金属MXenes构建了18种潜在的双功能铂单原子催化剂。在进一步考虑过电位、溶剂化效应和反应势垒等一些重要的实际应用因素后，只有其中四种，即CrNbCO-V-Pt、CrTaCO-V-Pt、CrNbCO-V-Pt和CrTaCO-V-Pt，被筛选为双功能氧还原反应/析氧反应（ORR/OER）催化剂。所有这些筛选出的单原子催化剂都源自基于铬的MXenes，这意味着基于铬的MXenes在设计双功能铂单原子催化剂方面具有重要意义。
