Immobilizing Metal Nanoparticles to Metal–Organic Frameworks with Size and Location Control for Optimizing Catalytic Performance

AuNi alloy nanoparticles were successfully immobilized to MIL-101 with size and location control for the first time by double solvents method (DSM) combined with a liquid-phase concentration-controlled reduction strategy. When an overwhelming reduction approach was employed, the uniform 3D distribution of the ultrafine AuNi nanoparticles (NPs) encapsulated in the pores of MIL-101 was achieved, as demonstrated by TEM and electron tomographic measurements, which brings light to new opportunities in the fabrication of ultrafine non-noble metal-based NPs throughout the interior pores of MOFs. The ultrafine AuNi alloy NPs inside the mesoporous MIL-101 exerted exceedingly high activity for hydrogen generation from the catalytic hydrolysis of ammonia borane

Immobilizing Metal Nanoparticles to Metal–Organic Frameworks with Size and Location Control for Optimizing Catalytic Performance

AuNi alloy nanoparticles were successfully immobilized to MIL-101 with size and location control for the first time by double solvents method (DSM) combined with a liquid-phase concentration-controlled reduction strategy. When an overwhelming reduction approach was employed, the uniform 3D distribution of the ultrafine AuNi nanoparticles (NPs) encapsulated in the pores of MIL-101 was achieved, as demonstrated by TEM and electron tomographic measurements, which brings light to new opportunities in the fabrication of ultrafine non-noble metal-based NPs throughout the interior pores of MOFs. The ultrafine AuNi alloy NPs inside the mesoporous MIL-101 exerted exceedingly high activity for hydrogen generation from the catalytic hydrolysis of ammonia borane

Immobilizing Extremely Catalytically Active Palladium Nanoparticles to Carbon Nanospheres: A Weakly-Capping Growth Approach

Ultrafine palladium nanoparticles (Pd NPs) supported on carbon nanospheres have been successfully synthesized using a facile methanol-mediated weakly-capping growth approach (WCGA) with anhydrous methanol as a mild reductant and a weakly capping agent. The Pd NPs show exceedingly high catalytic activity for 100% selective dehydrogenation of aqueous formic acid (FA) at ambient temperatures. The small size and clean surface of the Pd NPs greatly improve the catalytic properties of the as-prepared catalyst, providing an average rate of CO-free H₂ generation up to 43 L H₂ g_Pd^–1 min^–1 and a turnover frequency of 7256 h^–1 at 60 °C. These values are much higher than those obtained even with the most active catalyst reported thus far for heterogeneously catalyzed dehydrogenation of FA. This remarkably facile and effective methanol-mediated WCGA provides a powerful entry into ultrafine metal NPs with clean surface to achieve enhanced performance. Moreover, the catalytic results open up new avenues in the effective applications of FA for hydrogen storage

Immobilizing Highly Catalytically Active Noble Metal Nanoparticles on Reduced Graphene Oxide: A Non-Noble Metal Sacrificial Approach

In this work, we have developed a non-noble metal sacrificial approach for the first time to successfully immobilize highly dispersed AgPd nanoparticles on reduced graphene oxide (RGO). The Co₃(BO₃)₂ co-precipitated with AgPd nanoparticles and subsequently sacrificed by acid etching effectively prevents the primary AgPd particles from aggregation. The resulted ultrafine AgPd nanoparticles exhibit the highest activity (turnover frequency, 2739 h^–1 at 323 K) among all the heterogeneous catalysts for the dehydrogenation of formic acid to generate hydrogen without CO impurity. The sacrificial approach opens up a new avenue for the development of high-performance metal nanocatalysts

Diamine-Alkalized Reduced Graphene Oxide: Immobilization of Sub‑2 nm Palladium Nanoparticles and Optimization of Catalytic Activity for Dehydrogenation of Formic Acid

An efficient strategy to downsize metal nanoparticles (NPs) and provide basic sites located nearby for optimizing the catalytic performance of reduced graphene oxide (rGO)-supported metal catalysts has been explored, for the first time, by potent alkalization of rGO with diamine. By virtue of the coordination effects between the metal ions and the amine groups ligated to rGO, monodispersed Pd nanoparticles (diameter ≤1.5 nm) can be facilely anchored on the diamine-alkalized rGO by a simple reduction approach. The turnover frequency (TOF) for heterogeneously catalyzed decomposition of formic acid reaches 3810 h^–1 at 323 K, the highest value ever reported under ambient conditions compared with the other heterogeneous catalysts

Controlled Synthesis of Ultrafine Surfactant-Free NiPt Nanocatalysts toward Efficient and Complete Hydrogen Generation from Hydrazine Borane at Room Temperature

A sodium-hydroxide-assisted reduction approach has been developed to control the synthesis of ultrafine surfactant-free bimetallic NiPt nanoparticles (NPs) supported on nanoporous carbon, Maxsorb MSC-30. For the first time, this catalyst exerts exceedingly high catalytic activity for 100% selective conversion of hydrazine borane (HB) to hydrogen at room temperature. This remarkably facile and effective reduction approach provides a powerful entry into ultrafine alloy NPs to make full use of noble metals and achieve enhanced performance, where the compositions of the alloy can be widely adjusted and tailored. Moreover, the catalytic results open up new avenues in the effective application of HB as a promising hydrogen storage material

Engineering Electronic and Morphological Structure of Metal–Organic-Framework-Derived Iron-Doped Ni₂P/NC Hollow Polyhedrons for Enhanced Oxygen Evolution

The rational design of an oxygen electrocatalyst with low cost and high activity is greatly desired for realization of the practical water-splitting industry. Herein, we put forward a rational method to construct nonprecious-metal catalysts with high activity by designing the microstructure and modulating the electronic state. Iron (Fe)-doped Ni2P hollow polyhedrons decorated with nitrogen-doped carbon (Fe-Ni2P/NC HPs) are prepared by a sequential metal–organic-framework-templated strategy. Benefiting from the strong electronic coupling, rapid charge-transfer capability, and abundant catalytic active sites, the obtained Fe-Ni2P/NC HPs exhibit an impressive electrocatalytic performance toward the oxygen evolution reaction (OER) with an ultralow overpotential of 228 mV at a current density of 10 mA cm–2 and a small Tafel slope of 33.4 mV dec–1, superior to the commercial RuO2 and most reported electrocatalysts. Notably, this catalyst also shows long durability with an almost negligible activity decay over 210 h for the OER. Combining density functional theory calculations with experiments demonstrates that the doped Fe and the incorporated carbon effectively modulate the electronic structure, enhance the conductivity, and greatly reduce the energy barrier of the rate-determining step in the process of OER. Thus, fast OER kinetics is realized. Moreover, this synthetic strategy can be extended to the synthesis of Fe-NiS2/NC HPs and Fe-NiSe2/NC HPs with excellent OER performance and long-term durability. This work furnishes an instructive idea in pursuit of nonprecious-metal materials with robust electrocatalytic activity and long durability

Introduction of Multicomponent Dyes into 2D MOFs: A Strategy to Fabricate White Light-Emitting MOF Composite Nanosheets

Metal–organic frameworks (MOFs) have been extensively studied in host–guest chemistry by means of ultrahigh porosities, tunable channels, and component diversities. As the host matrix, MOFs exhibit immense potential in the preparation of single-phase white light-emitting (SPWLE) materials. Nonetheless, it is a great challenge that the size of the introduced guest molecules is limited by MOF pores, which affects the WLE optimization. In this work, two-dimensional (2D) MOFs are first utilized as the host matrices to simultaneously encapsulate red–green–blue fluorescent dyes for SPWLE. Various dyes@2D MOF composites with high-quality WLE performances and ultrathin nanosheet morphologies are directly assembled from 2D MOF precursors and dyes in high yields. Owing to the flexible interlamellar space of 2D MOFs, different types and sizes of guests can be easily introduced, which greatly expands the range of available MOF hosts and guests, making the WLE much more tunable. The strategy of employing 2D MOFs as the host matrices to introduce multicomponent dyes for SPWLE nanosheets resolves the restriction of MOF pores on the guest molecule size and opens a new avenue to rationally design and prepare SPWLE nanosheets that are highly solution-processable

Ba₁₀In₂Mn₁₁Si₃O₁₂S₁₈: First Hexanary Oxychalcogenide Containing an Infrequent Three-Dimensional Noncentrosysmmetric Framework

Noncentrosymmetric (NCS) oxychalcogenides have attracted great attention in recent years due to their immense potential as candidates for IR nonlinear-optical (NLO) applications. Despite notable advancements in this field, the discovery of oxychalcogenides with three-dimensional (3D) framework structures remains a formidable challenge. In this study, we report the discovery of the first hexanary oxychalcogenide, Ba10In2Mn11Si3O12S18, exhibiting second-order NLO activity, using a high-temperature solid-phase method. This compound showcases a novel structure type, featuring an uncommon NCS 3D [In2Mn11Si3O12S18]20– framework formed by vertex-sharing [(Mn/In)S6] octahedra, [(Mn/In)OS3] tetrahedra, and [SiO4] tetrahedra, with charge-balanced Ba2+ cations occupying the channels. Our study serves as a source of inspiration for researchers to further investigate the synthesis of novel NLO-active oxychalcogenides with 3D frameworks