Supported liquid-phase catalysts (SLPCs) combine the advantages of homogenous liquid-phase catalysts and heterogeneous catalysis (e.g., controllability of active centers and efficient product–catalyst separation). Generally, SLPCs manifest as a liquid-phase catalyst film or droplet adsorbed onto the surface of a porous support, such as ionic liquid-phase catalysts. Here, we extend this idea and develop a solvent-free liquid-phase catalyst supported on hollow spheres. We report sandwich-like B₂O₃@BPO₄ hollow spheres synthesized through a one-step template-free method. At reaction temperatures (>450 °C), melted B₂O₃ supported on the surface of BPO₄ hollow spheres acts as a catalytically active species for the selective oxidative dehydrogenation of propane to propene, with an excellent productivity of 0.79 gC₃H₆ g_cat⁻¹ h⁻¹ and a high stability at 550 °C. We also found a phenomenon of tertiary aggregation during the formation of this sandwich-like hollow sphere. Additionally, the kinetic experiments indicate oxygen activation on the B₂O₃@BPO₄ surface and second-order rate dependence with respect to the partial pressure of propane. This work may open a new avenue for the design and construction of metal-free oxides used as high-temperature SLPCs.

负载型液相催化剂（SLPC）结合了均相液相催化剂和非均相催化的优点（例如，活性中心的可控制性和有效的产物-催化剂分离）。通常，SLPC表现为吸附在多孔载体（如离子型液相催化剂）表面上的液相催化剂膜或液滴。在这里，我们扩展了这种想法，并开发了负载在空心球上的无溶剂液相催化剂。我们报告通过一步模板免费方法合成的三明治状B ₂ O ₃ @BPO ₄中空球。在反应温度（> 450°C）下，熔融的B ₂ O ₃负载在BPO ₄的表面上中空球是丙烷选择性氧化脱氢为丙烯的催化活性物质，具有0.79 gC ₃ H ₆ g _cat ^-1 h ^-1的优异生产率，并在550°C下具有很高的稳定性。我们还发现了这种夹心状空心球形成过程中的第三级聚集现象。此外，动力学实验表明B ₂ O ₃ @BPO ₄表面上的氧活化和相对于丙烷分压的二级速率依赖性。这项工作可能为用作高温SLPC的无金属氧化物的设计和构造开辟新的途径。