Present study deals with hematite/M (M = Au, Pd) catalysts converted from a double-hollow Prussian blue microstructure (DHPM). The unique Prussian blue (PB) microstructure (MS) is prepared by a template-free solvothermal synthetic route in a single-step reaction. An amine-functionalized silicate sol–gel matrix (SSG) has served as the structure-directing agent cum stabilizer for making DHPM. Synthesized DHPM is having a unique structure: a hollow core and an in situ etched porous surface. Growth mechanism is explored and revealed by analyzing several experimental parameters such as HCl concentration, Fe source, effect of the added EtOH, silane concentration, and role of silanes’ amine groups. It is identified that the superstructure consisted of well-aligned PB cubes growing radially from the core of the superstructure. Metal (Au and Pd) nanoparticles (NPs) are deposited on both interior and exterior of the PB MS through galvanic displacement reaction, and thus metal NP-loaded hematite phase iron oxide (α-Fe₂O₃) nanomaterials were derived by annealing them in air. Catalytic activities of the hematite/M(M = Au, Pd) MS are investigated toward simultaneous catalytic reduction of o-nitrophenol and p-nitrophenol. The resultant hematite/Pd MS showed high structural stability and catalytic active sites than the hematite/Au MS, which enhances the catalytic properties for the simultaneous catalytic reduction of both nitrophenols.

中文翻译：

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源自双空心普鲁士蓝微结构的赤铁矿/ M（M = Au，Pd）催化剂：邻硝基和对硝基苯酚的同时催化还原

目前的研究涉及从双空心普鲁士蓝微结构（DHPM）转换而来的赤铁矿/ M（M = Au，Pd）催化剂。独特的普鲁士蓝（PB）微结构（MS）通过无模板溶剂热合成路线在一步反应中制备。胺官能化的硅酸盐溶胶-凝胶基质（SSG）已作为结构导向剂和稳定剂用于制造DHPM。合成的DHPM具有独特的结构：空心和原位蚀刻的多孔表面。通过分析几个实验参数来探索和揭示其生长机理，例如HCl浓度，Fe来源，添加的EtOH的影响，硅烷浓度以及硅烷胺基的作用。可以看出，上部结构由从上部结构的芯部径向生长的排列良好的PB立方体组成。金属（Au和Pd）的纳米颗粒（NP）被沉积在内部和通过电镀置换反应的PB MS的外部，并且因此金属NP-加载的赤铁矿相的氧化铁（α-的Fe ₂ ö ₃）纳米材料通过退火它们衍生在空中。研究了赤铁矿/ M（M = Au，Pd）MS对同时催化还原邻硝基苯酚和p的催化活性-硝基苯酚。所得的赤铁矿/ Pd MS与赤铁矿/ Au MS相比，具有较高的结构稳定性和催化活性位，这增强了同时催化还原两种硝基酚的催化性能。