Ultrafine Ruthenium Clusters Shell‐Embedded Hollow Carbon Spheres as Nanoreactors for Channel Microenvironment‐Modulated Furfural Tandem Hydrogenation

Abstract

Rationally modulating the catalytic microenvironment is important for targeted induction of specific molecular behaviors to fulfill complicated catalytic purposes. Herein, a metal pre‐chelating assisted assembly strategy is developed to facilely synthesize the hollow carbon spheres with ultrafine ruthenium clusters embedded in pore channels of the carbon shell (Ru@Shell‐HCSs), which can be employed as nanoreactors with preferred electronic and geometric catalytic microenvironments for the efficient tandem hydrogenation of biomass‐derived furfural toward 2‐methylfuran. The channel‐embedding structure is proved to confer the ultrafine ruthenium clusters with an electron‐deficient property via a reinforced interfacial charge transfer mechanism, which prompts the hydrogenolysis of intermediate furfuryl alcohol during the tandem reaction, thus resulting in an enhanced 2‐methylfuran generation. Meanwhile, lengthening the shell pore channel can offer reactant molecules with a prolonged diffusion path, and correspondingly a longer retention time in the channel, thereafter delivering an accelerated tandem hydrogenation progression. This paper aims to present a classic case that emphasizes the critical role of precisely controlling the catalytic microenvironment of the metal‐loaded hollow nanoreactors in coping with the arduous challenges from multifunctional catalyst‐driven complex tandem reactions.

Kinetics Driven by Hollow Nanoreactors: An Opportunity for Controllable Catalysis

“…Very recently, a typical case was reported by Lu et al, in which both the electronic and geometric microenvironments of hollow nanoreactors were modulated to facilitate the tandem hydrogenation of furfural to 2-methylfuran. [94] A metal pre-chelating assisted assembly strategy was developed to synthesize the Ru@Shell-HCSs with ruthenium clusters embedded in pore channels of the shell of hollow carbon spheres. The special channel-embedded structure was shown to strengthen the electron transfer from Ru clusters to the carbon channels, thereby making the Ru clusters significantly electron-deficient, which could prompt the furfuryl alcohol hydrogenolysis, the rate-determining step of the tandem furfural hydrogenation.…”

“…As mentioned earlier, a further exploitation of the systematic effects of hollow nanoreactors in terms of both electronics and geometry to promote preferred kinetic behaviors is considered as a requisite approach for achieving a better controllable catalysis with specific purposes. Very recently, a typical case was reported by Lu et al., in which both the electronic and geometric microenvironments of hollow nanoreactors were modulated to facilitate the tandem hydrogenation of furfural to 2‐methylfuran [94] . A metal pre‐chelating assisted assembly strategy was developed to synthesize the Ru@Shell‐HCSs with ruthenium clusters embedded in pore channels of the shell of hollow carbon spheres.…”

“…(b7) mechanism for the tandem hydrogenation of furfural over Ru@Shell-HCSs nanoreactors. Reproduced with permission from Ref [94]. Copyright 2022, Wiley-VCH.…”

Accelerated Catalytic Ozonation in a Mesoporous Carbon-Supported Atomic Fe–N4 Sites Nanoreactor: Confinement Effect and Resistance to Poisoning

“…11 The spatial confinement reaction in nanostructures is a new engineering method to strengthen mass transfer and redox processes. 12,13 Nanoscale confinement affects the interaction between the guest molecules and the reactive surface, resulting in changes in behavior relative to the bulk phase (e.g., accumulation, distribution, and binding), and ultimately changes the kinetics of various redox reactions. 14,15 Previous studies have shown that the confined microenvironment changes the energy and kinetics of the catalytic reaction by imposing specific orientation and conformation on the reactant molecules.…”

Linear diketones as next-generation biomass-derived platform molecules: from heterogeneous catalytic synthesis to supply of high-end chemicals

“…These platform molecules that are obtained from cellulose, hemicellulose or lignin have been reported to be efficiently converted into a wide range of value-added chemicals and liquid fuels through various upgrading strategies. [42][43][44][45][46] Biomass-derived ketones are an important class of platform molecules, which can be classified as cyclic ketones and linear ketones. Among these ketones, the linear diketones have received extensive research attention in recent years due to their inherent high value and huge application potential.…”