Graphical Abstract

Efficient hydrogen production via photocatalysis with high utilization efficiency of Pt cocatalyst is of great importance for sustainable development. In this work, we report an in situ auto-reduction strategy to encapsulate highly dispersed Pt clusters inside the cages of MIL-125-NH2. The amino groups in MIL-125-NH2 first react with formaldehyde to form reducing groups (i.e., –NH-CH2OH), which can in situ auto-reduce the confined Pt2+ ions to ultrasmall Pt clusters within the cavities. With optimized Pt content, photocatalytic H2 production over the obtained Pt(1.5)/MIL-125-NH-CH2OH catalyst with 1.43 wt.% Pt loading achieved as high as 4, 496.4 µmol·g−1·h−1 under visible light (λ > 420 nm) due to the facilitated transfer and separation of the photo-induced charger carriers arising from the synergetic effects between highly dispersed Pt clusters and MIL-125-NH-CH2OH framework. This in situ auto-reduction strategy may be extended to encapsulate various kinds of metal or alloy clusters/nanoparticles within amino-functioned metal-organic frameworks (MOFs) with superior properties and excellent performance.
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