posted on 2024-01-03, 01:16authored byJe-Wei Chang, Kuan-Hsuan Su, Chih-Wen Pao, Jin-Jia Tsai, Chun-Jen Su, Jeng-Lung Chen, Lian-Ming Lyu, Chun-Hong Kuo, An-Chung Su, Hsiao-Ching Yang, Ying-Huang Lai, U-Ser Jeng
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 (Pt1) 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 Pt1–PTA pairs, facilitated
by the arrayed silicate nanochannels, demonstrate high and stable
efficiency with a hydrogen production rate of ca. 300 mmol/h/gPtapproximately twice that of the best-reported Pt
efficiency in polyoxometalate-based photocatalytic systems.