Chang Je-Wei, Su Kuan-Hsuan, Pao Chih-Wen, Tsai Jin-Jia, Su Chun-Jen, Chen Jeng-Lung, Lyu Lian-Ming, Kuo Chun-Hong, Su An-Chung, Yang Hsiao-Ching, Lai Ying-Huang, Jeng U-Ser
Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300044, Taiwan.
National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 300092, Taiwan.
ACS Nano. 2024 Jan 16;18(2):1611-1620. doi: 10.1021/acsnano.3c09656. Epub 2024 Jan 2.
Single-atom catalysts, known for their high activity, have garnered significant interest. Currently, single-atom catalysts were prepared mainly on 2D substrates with random distribution. Here, we report a strategy for preparing arrayed single Pt (Pt) atoms, which are templated through coordination with phosphotungstic acids (PTA) intercalated inside hexagonally packed silicate nanochannels for a high single Pt-atom loading of ca. 3.0 wt %. X-ray absorption spectroscopy, high-angle annular dark-field scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy, in conjunction with the density-functional theory calculation, collectively indicate that the Pt single atoms are stabilized via a four-oxygen coordination on the PTA within the nanochannels' inner walls. The critical reduction in the Pt-adsorption energy to nearly the cohesive energy of Pt clustering is attributed to the interaction between PTA and the silicate substrate. Consequently, the transition from single-atom dispersion to clustering of Pt atoms can be controlled by adjusting the number density of PTA intercalated within the silicate nanochannels, specifically when the number ratio of Pt atoms to PTA changes from 3.7 to 18. The 3D organized Pt-PTA pairs, facilitated by the arrayed silicate nanochannels, demonstrate high and stable efficiency with a hydrogen production rate of ca. 300 mmol/h/g─approximately twice that of the best-reported Pt efficiency in polyoxometalate-based photocatalytic systems.
以高活性著称的单原子催化剂引起了广泛关注。目前，单原子催化剂主要制备在二维随机分布的基底上。在此，我们报道了一种制备排列有序的单铂（Pt）原子的策略，该策略通过与插层在六方堆积硅酸盐纳米通道内的磷钨酸（PTA）配位作为模板，实现了约3.0 wt%的高单铂原子负载量。结合密度泛函理论计算，X射线吸收光谱、高角度环形暗场扫描透射电子显微镜和能量色散X射线光谱共同表明，铂单原子通过纳米通道内壁上PTA的四氧配位得以稳定。铂吸附能临界降低至接近铂团簇的内聚能，这归因于PTA与硅酸盐基底之间的相互作用。因此，通过调节插层在硅酸盐纳米通道内的PTA的数密度，特别是当铂原子与PTA的数量比从3.7变为18时，可以控制铂原子从单原子分散到团簇的转变。由排列有序的硅酸盐纳米通道促进形成的三维有序铂 - PTA对表现出高且稳定的效率，产氢速率约为300 mmol/h/g，约为基于多金属氧酸盐的光催化体系中报道的最佳铂效率的两倍。
