Kwak In Hye, Kwon Ik Seon, Kim Ju Yeon, Zewdie Getasew Mulualem, Lee Seung Jae, Yoo Seung Jo, Kim Jin-Gyu, Park Jeunghee, Kang Hong Seok
Department of Advanced Materials Chemistry, Korea University, Sejong 339-700, Republic of Korea.
Institute for Application of Advanced Materials, Jeonju University, Chonju, Chonbuk 55069, Republic of Korea.
ACS Nano. 2022 Sep 27;16(9):13949-13958. doi: 10.1021/acsnano.2c03157. Epub 2022 Sep 13.
Composition modulation of transition metal dichalcogenides is an effective way to engineer their crystal/electronic structures for expanded applications. Here, fully composition-tuned WNbSe alloy nanosheets were produced via colloidal synthesis. These nanosheets ultimately exhibited a notable transition between WSe and NbSe hexagonal phases at = 0.6. As approaches 0.6, point doping is converted into cluster doping and eventually separated domains of WSe and NbSe. Extensive density functional theory calculations predicted the composition-dependent crystal structures and phase transitions, consistently with the experiments. The electrocatalytic activity for the hydrogen evolution reaction (HER) in acidic electrolyte was significantly enhanced at = 0.2, which was linked with the dband center. The Gibbs free energy for the H adsorption at various basal and edge sites supported the enhanced HER performance of the metallic alloy nanosheets. We suggested that the dispersed doping structures of Nb atoms resulted in the best HER performance. Our findings highlight the significance of composition tuning in enhancing the catalytic activity of alloys.
过渡金属二硫属化物的成分调制是一种有效的方法，可用于设计其晶体/电子结构以实现更广泛的应用。在此，通过胶体合成制备了完全成分调谐的WNbSe合金纳米片。这些纳米片最终在x = 0.6时在WSe和NbSe六方相之间表现出明显的转变。当x接近0.6时，点掺杂转变为团簇掺杂，最终形成WSe和NbSe的分离域。广泛的密度泛函理论计算预测了与成分相关的晶体结构和相变，与实验结果一致。在x = 0.2时，酸性电解质中析氢反应（HER）的电催化活性显著增强，这与d带中心有关。各种基面和边缘位点上H吸附的吉布斯自由能支持了金属合金纳米片增强的HER性能。我们认为Nb原子的分散掺杂结构导致了最佳的HER性能。我们的研究结果突出了成分调谐在增强合金催化活性方面的重要性。
