Engineering of anchor sites and reaction time to efficiently synthesize high loading and stable sub-nanocluster catalysts

Abstract

The preparation of sub-nanoclusters (SNCs) with high loading and stability by a rapid, green strategy is one of the main challenges facing researchers. In this study, we developed a novel strategy by engineering anchor sites and reaction time to efficiently synthesize a series of high loading and stable noble metal SNCs via a scalable solvent-free microwave synthesis method (expressed as M/C-X, where M represents Pt, Pd, Ru, C represents KB, CNT, rGO, X represents O, N, S). The efficient synthesis method also provides a high yield (93.1%) and takes only 40 s. In this paper, the number and type of functional groups is optimized so that the number of functional groups is neither so excessive as to be agglomerated, nor too scanty to be underloaded, thus achieving the high loading and stability of SNCs. When the O functional group was 8.9 at%, the SNCs reached the maximum loading (47.1 wt% or 5.3 at%). Meanwhile, the presence of the strong metal-support interaction (SMSI) allows the SNCs to be firmly anchored to the support, which greatly enhances their stability. The mass activity of Pt_0.6/KB-O_S5-40 with the highest loading is 27.3 A mg_Pt⁻¹ at 50 mV in acidic HER, which is much better than that of commercial Pt/C (4.3 A mg_Pt⁻¹). It is one of the catalysts with the highest mass activity so far (Table S3, ESI). After 5 days of durability testing, the catalytic performance of Pt_0.6/KB-O_S5-40 remains almost unchanged.