Ordered Mesopore Confined Pt Nanoclusters Enable Unusual Self-Enhancing Catalysis

Abstract

As an important kind of emerging heterogeneous catalyst for sustainable chemical processes, supported metal cluster (SMC) catalysts have received great attention for their outstanding activity; however, the easy aggregation of metal clusters due to their migration along the substrate's surface usually deteriorates their activity and even causes catalyst failure during cycling. Herein, stable Pt nanoclusters (NCs, ∼1.06 nm) are homogeneously confined in the uniform spherical mesopores of mesoporous titania (mpTiO 2 ) by the interaction between Pt NCs and metal oxide pore walls made of polycrystalline anatase TiO 2 . The obtained Pt-mpTiO 2 exhibits excellent stability with well-retained CO conversion (∼95.0%) and Pt NCs (∼1.20 nm) in the long term water−gas shift (WGS) reaction. More importantly, the Pt-mpTiO 2 displays an unusual increasing activity during the cyclic catalyzing WGS reaction, which was found to stem from the in situ generation of interfacial active sites (Ti 3+ -O v -Pt δ+ ) by the reduction effect of spillover hydrogen generated at the stably supported Pt NCs. The Pt-mpTiO 2 catalysts also show superior performance toward the selective hydrogenation of furfural to 2-methylfuran. This work discloses an efficient and robust Pt-mpTiO 2 catalyst and systematically elucidates the mechanism underlying its unique catalytic activity, which helps to design stable SMC catalysts with self-enhancing interfacial activity in sustainable heterogeneous catalysis.

Pore Engineering for High Performance Porous Materials

“…The loading facilitated the generation of interfacial active sites (Ti 3+ -O v -Pt δ+ ) during the reaction, thereby enhancing the cyclic catalytic activity. 24 If the porous material itself lacks catalytic activity, large pores can still facilitate the loading of catalytic substances, especially for large biomolecules such as enzymes. Guangshan Zhu and colleagues employed a strategy of synergistic assembly using multiple ligands to construct framework materials with large pores.…”

“…In addition, Prof. Yonghui Deng and Dongyuan Zhao reported that Pt clusters can be homogeneously confined in the uniform spherical mesopores of mesoporous TiO 2 , which is based on the interaction between Pt nanoclusters and metal oxide pore walls. The loading facilitated the generation of interfacial active sites (Ti 3+ -O v -Pt δ+ ) during the reaction, thereby enhancing the cyclic catalytic activity …”

Self-Enhanced Catalytic Activity of Pt/TiO2 via Electronic Metal–Support Interaction

“…However, SMSI can also cause encapsulation of active metals by the reducible supports, limiting the exposure of interfacial sites and suppressing reaction activities. , Thus, constructing an MSI with suitable strength is crucial for maintaining catalytic activity and durability. In a recent issue of ACS Central Science , Deng, Wu, Zou, and co-workers reported a supported metal cluster catalyst Pt-mpTiO 2 with confined Pt nanoclusters . This catalyst design stabilizes the Pt nanoclusters and introduces a favorable medium MSI effect, providing a substantial amount of Ti 3+ -O v -Pt δ+ interfacial active sites and exhibiting superior catalytic performance compared to traditional Pt/TiO 2 catalysts.…”

“…(F) Scheme of the mechanism and effect of increasing O v in used Pt-mpTiO 2 . Reproduced with permission from ref . Copyright 2022 The Authors.…”

“…In a recent issue of ACS Central Science, Deng, Wu, Zou, and co-workers reported a supported metal cluster catalyst Pt-mpTiO 2 with confined Pt nanoclusters. 7 This catalyst design stabilizes the Pt nanoclusters and introduces a favorable medium MSI effect, providing a substantial amount of Ti 3+ -O v -Pt δ+ interfacial active sites and exhibiting superior catalytic performance compared to traditional Pt/TiO 2 catalysts.…”