Overturned Loading of Inert CeO₂to Active Co₃O₄for Unusually Improved Catalytic Activity in Fenton‐Like Reactions

Abstract

In the past decades, numerous efforts have been devoted to improving the catalytic activity of nanocomposites by either exposing more active sites or regulating the interaction between the support and nanoparticles while keeping the structure of the active sites unchanged. Here, we report the fabrication of a Co 3 O 4 À CeO 2 nanocomposite via overturning the loading direction, i.e., loading an inert CeO 2 support onto active Co 3 O 4 nanoparticles. The resultant catalyst exhibits unexpectedly higher activity and stability in peroxymonosulfate-based Fenton-like reactions than its analog prepared by the traditional impregnation method. Abundant oxygen vacancies (O v with a Coare generated as new active sites to facilitate the cleavage of the peroxide bond to produce SO 4 *Àand accelerate the rate-limiting step, i.e., the desorption of SO 4 *À , affording improved activity. This strategy is a new direction for boosting the catalytic activity of nanocomposite catalysts in various scenarios, including environmental remediation and energy applications.

Disentangling Local Interfacial Confinement and Remote Spillover Effects in Oxide–Oxide Interactions

“…Metal oxides have been widely used as active catalysts in many heterogeneous catalytic reactions. − The surface and interface of the oxide catalysts are usually considered as the active sites for catalytic reactions, − and thus, it is of great significance to optimize the surface/interface structure for maximizing the catalytic performance. − Among all, oxide catalysts can be well supported on solid surfaces and the formed oxide–support interfaces strongly influence the surface reactivity. For instance, oxide nanostructures supported on metal surfaces are usually metastable but highly active, which has been discussed in terms of the interface confinement effect in the so-called inverse catalysts. − For oxides supported on oxide surfaces, their structure and catalytic performance are also affected by the oxide–oxide interfaces. − Although it is well known that the oxide–oxide interaction plays an important role in oxide catalysis, many diverse and even contradictory interface phenomena have been observed in the oxide/oxide catalysts, which are sensitively dependent on oxide supports, , oxide catalyst loading, preparation procedure, , and others. , …”

Enhanced catalytic activity of ZnO–CuO–Co3O4 composites achieved using a mechanochemical method for effective Fenton-like dye removal: the generation and catalytic mechanism of various superficial active sites

“…Various methods, including heteroatom doping, 15,18–21 heterojunction formation, 22–24 element non-stoichiometry and morphological control, 25–28 have been explored to construct OVs on a catalyst surface to ameliorate their catalytic activity in AOPs. As a typical mechanochemical method, ball milling has been widely applied in material engineering because of its low-cost operation and feasible up-scaling application.…”

“…17 Significantly, the OVs with localized electrons on the surface of bismuth oxychloride (BiOCl) were demonstrated to be new types of ''Fenton-catalytic centers'' to decompose H 2 O 2 into OH in spite of the poor catalysis of BiOCl. 12 Various methods, including heteroatom doping, 15,[18][19][20][21] heterojunction formation, [22][23][24] element non-stoichiometry and morphological control, [25][26][27][28] have been explored to construct OVs on a catalyst surface to ameliorate their catalytic activity in AOPs. As a typical mechanochemical method, ball milling has been widely applied in material engineering because of its low-cost operation and feasible up-scaling application.…”