Exploring the Fundamental Roles of Functionalized Ligands in Platinum@Metal–Organic Framework Catalysts

Abstract

The metal nodes, functionalized ligands, and uniform channels of metal–organic frameworks (MOFs) are typically utilized to regulate the catalytic properties of metal nanoparticles (MNPs). However, though the ligand functionalization could impact the properties of the metal nodes and channels, which might further regulate the catalytic activity and selectivity of MNPs, related research in the design of MNP/MOF catalysts was usually neglected. Herein, we synthesized a series of Pt@UiO-66 composites (Pt@UiO-66-NH2, Pt@UiO-66-SO3H, and Pt@UiO-66) with slightly different organic ligands, which enhanced steric hindrance and contributed to multipathway electron transfer in selective hydrogenation of linear citronellal. The selectivity toward citronellol was gradually improved along with the increased size of functional groups (hydrogen, amino groups, and sulfo groups) on organic ligands, which enhanced steric hindrance provided by channels. In addition, the X-ray photoelectron spectroscopy measurements also revealed that the electronic state of Pt NPs was regulated through multipathway electron transfer from Pt NPs to metal nodes, between organic ligands and Pt NPs/metal nodes. Our research proved that the ligand functionalization altered physiochemical properties of the channels and metal nodes, further together managing the catalytic performance of Pt NPs through enhanced steric hindrance and multi-pathway electron transfer.

The Role of Defects in Metal–Organic Frameworks for Nitrogen Reduction Reaction: When Defects Switch to Features

“…Among them, a novel kind of porous material metal–organic frameworks (MOFs), consisting of metal nodes linked by organic ligands for creating bulk structures, have grown up in electrocatalysis over the last few years owing to their tailorable structure, high surface area, high porosity, well‐defined pore size distribution, and low density. [ 30,31 ] These unique properties guarantee MOFs to be applied in different fields, including catalysis, [ 32,33 ] luminescence, [ 34 ] gas sorption, and separation. [ 35 ] In fact, 1) in MOFs, the organic ligands and metal nodes are connected by relatively weak coordination bonds, which could be easily broken.…”

Luminescent porous metal–organic gels for efficient adsorption and sensitive detection of chlortetracycline hydrochloride assisted by smartphones and a test paper-based analytical device

“…Metal-organic gels (MOGs), the analogues of metal-organic frameworks (MOFs), are composed of organic ligands and metal ions, and possess hierarchical pore structures, large surface areas, abundant active sites and high mechanical/ thermal stability. [7][8][9][10][11][12] These materials show great potential in adsorption, sensing and catalysis. [13][14][15][16][17][18] Among them, binary MOGs have become the more suitable candidates for adsorption due to the bigger surface areas deriving from the heterogeneity, which ensures pollutant removal because of their relatively higher adsorption amounts.…”

Tuning the electronic property of Pd nanoparticles by encapsulation within ZIF-67 shells towards enhanced performance in 1,3-butadiene hydrogenation

“…21,22 For instance, Huo et al used a simple ligand design strategy to change the functional groups on MOFs to facilitate multipath electron transfer between Pt NPs, metal nodes and organic ligands, thereby changing the activity and selectivity of citronellal hydrogenation. 23 In addition, Jiang et al explored the electronic interaction between the different functional groups of UiO-66-X and Pd NPs, and the hydrogenation activity towards benzoic acid is found to be closely related to the electronic transfer. 14 The above-mentioned progress mainly adjust the electronic properties of MNPs with the help of the tailored functional groups dangling on the ligand/metal cluster to promote the synergistic interaction, thereby improving the performance of the catalyst.…”