Incomplete charge transfer bestows significant sintering resistance for metal nanoparticles on two-dimensional graphyne†

Understanding and thus relieving the thermal-induced sintering effect of supported nanocatalysts is a research focus to propel their practical applications. While the metal–support interaction (MSI) is recognized to play a central role in determining the sintering resistance of metal nanocatalysts, the underlying nexus for the MSI-sintering mechanism is almost elusive for the community. Here, we report the anti-sintering mechanism for metal nanoparticles on two-dimensional (2D) hydrogen-substituted graphyne (HsGY), which is endowed by their incomplete charge transfer interaction (ICTI). By comparing the different sintering behaviors of metal nanoparticles on two kinds of 2D supports (HsGY and graphene) via systematic in situ transmission electron microscopy (TEM) experiments and theoretical simulations, it is suggested that the significant sintering resistance of supported nanoparticles on HsGY originates from the Ostwald ripening mechanism due to strong ICTI, whereas graphene has only weak MSI with nanoparticles and hence the dominant mechanism of sintering is particle migration and coalescence. The direct disclosure of such a relationship in “thermal stability-sintering mechanism-ICTI/MSI” for supported catalysts may shed light on the pertinent selection of substrate materials and hence the design of super-stable nanocatalysts.