Stabilizing gold nanoparticles（AuNPs） within a desired size range is critical to realize their promising catalytic performance in many important reactions.Herein,we investigate the anti-sintering properties of cubic mesoporous silica（FDU-12） as a function of pore entrance size.Simple adjustments to the type of organic template and reaction temperature enable the successful synthesis of FDU-12 with controllable entrance sizes（ 3,3-5 and 7 nm）.Excellent anti-sintering properties are observed for FDU-12 with a sub-5-nm entrance size（3-5 nm） over a wide loading concentration（1.0-8.3 wt%） and the AuNPs can be stabilized within a 4.5-5.0-nm range after calcination at 550 ℃in air for 5 h.Smaller entrance size（ 3 nm） prevents ingress of 3-nm AuNPs to the mesopores and results in low loading capacity and sintering.Conversely,FDU-12 possessing a larger entrance size（7 nm） shows promising anti-sintering properties at high loading concentrations,although catalytic performance is significantly lost at lower concentrations（e.g.2.1 wt%,14.2 ± 5.5 nm）.Different anti-sintering mechanisms are proposed for each of the different FDU-12 entrance sizes.Additionally,catalytic data indicates that the obtained 4.5-nm AuNPs supported on FDU-12 with a sub-5-nm entrance size exhibit excellent mass-specific activity（1544 mmol g_（Au）^（-1） h^（-1）） and selectivity（ 99%）at 230 ℃ for the gas-phase selective oxidation of cyclohexanol.
