The synthesis of hierarchical nanosized zeolite materials without growth modifiers and mesoporogens remains a substantial challenge. Herein, we report a general synthetic approach to produce hierarchical nanosized single‐crystal aluminophosphate molecular sieves by preparing highly homogeneous and concentrated precursors and heating at elevated temperatures. Accordingly, aluminophosphate zeotypes of LTA (8‐rings), AEL (10‐rings), AFI (12‐rings), and ‐CLO (20‐rings) topologies, ranging from small to extra‐large pores, were synthesized. These materials show exceptional properties, including small crystallites (30–150 nm), good monodispersity, abundant mesopores, and excellent thermal stability. A time‐dependent study revealed a non‐classical crystallization pathway by particle attachment. This work opens a new avenue for the development of hierarchical nanosized zeolite materials and understanding their crystallization mechanism.

coordinative dopants (N, O, S, P, etc.) [8] and metal-support interactions. [9] Spectroscopic studies and computational simulations suggest that MN x related species are the catalytic sites for the ORR or/and OER. [8c,10] Although some MN x C catalysts have already shown high catalytic activity for ORR or/and OER in threeelectrode-system, their exposed active sites are still too little to meet the requirements of practical applications in batteries. [11] Increasing atomic MN x moieties' density and utilization rate is a well-known approach to improving catalytic performance but remains challenging. [12] Currently, high-temperature pyrolysis is a necessary procedure to obtain atomic MN x moieties on carbon matrix but usually leads to the migration and aggregation of metal atoms driven by the high surface energy offered by the calcination process. [8d] Additionally, isolated metal atoms have inherently high surface free energy and tend to form clusters and nanoparticles, which have low activity for ORR or/and OER, and need to be removed by post acid treatment. [13] Although researchers have made a lot of attempts to increase the metal loading, the content of the atomically dispersed metal is usually below 3 wt%. [7c,12b,14] For example, Shui et al. prepared FeNC catalysts with single Fe atom content of 2.78 wt % by pyrolysis of SiO 2 -protected zeolitic imidazolate frameworks-8 (ZIF-8). [12b] Lin et al. prepared FeN-doped graphene nanosheets (FeN/ GNs) with 2.16 wt% Fe content through a ZIF-8 thermal melting strategy. [14a] Wu et al. reported a two-step doping and adsorption process to obtain atomically dispersed MnN 4 sites on partially graphitic carbon (MnNC) with the Mn content up to 3.03 wt%. [7c] Additionally, the utilization rate of M-N x moieties will dramatically reduce in high metal loading catalysts. Many M-N x moieties will be buried in carbon matrixes. Exposed site density (SD e ) has been a predominant factor in describing the active sites density and mass transfer ability of M-N x -C catalysts. SD e is the number of exposed active sites normalized to the mass of catalysts. Shui et al. display that when Fe content increases from 0.28 to 2.78 wt%, the utilization rate of FeN x moieties reduces from 43.5 to 11.4%, obtaining a maximum exposed active site density of 3.4 × 10 19 sites g −1 . [12b] Jia et al. report a chemical vapor deposition method to synthesize FeNC with the recorded exposed active site density of 1.92 × 10 20 sites g −1 . [15] Unfortunately, the exposed active site density is still not enough to efficiently catalyze ORR and OER.Here, we report a double steric hindrance strategy to synthesize single-atom iron catalysts with the recorded iron loading Atomically dispersed iron embedded carbon is a promising bifunctional catalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), but its exposed iron sites must be increased. Herein, the authors propose a double steric hindrance strategy by using zeolitic imidazolate frameworks-8 as the fi...

The synthesis of hierarchical nanosized zeolite materials without growth modifiers and mesoporogens remains a substantial challenge. Herein, we report a general synthetic approach to produce hierarchical nanosized single‐crystal aluminophosphate molecular sieves by preparing highly homogeneous and concentrated precursors and heating at elevated temperatures. Accordingly, aluminophosphate zeotypes of LTA (8‐rings), AEL (10‐rings), AFI (12‐rings), and ‐CLO (20‐rings) topologies, ranging from small to extra‐large pores, were synthesized. These materials show exceptional properties, including small crystallites (30–150 nm), good monodispersity, abundant mesopores, and excellent thermal stability. A time‐dependent study revealed a non‐classical crystallization pathway by particle attachment. This work opens a new avenue for the development of hierarchical nanosized zeolite materials and understanding their crystallization mechanism.