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Despite the widespread use of bimetallic nanomaterial catalysts, a molecular-level understanding of the synergistic effects is unclear, limiting our ability to pre-design “tailor-made” bimetallic catalysts. We chose bimetallic Au1Ag24(SR)18 and Au25−xAgx(SR)18 (x = 2–6) nanoclusters (NCs) as models to investigate the relationship between microstructure and performance, comparing them with the corresponding monometallic NCs. Experimental and theoretical analyses demonstrated that the Au@Ag kernel was the essential structural feature for high activity and super stability of Au1Ag24(SR)18 catalyst in the alkynylation of CF3-ketone. This structure-activity relationship was successfully extended to other bimetallic systems bearing an Au@Ag kernel, such as Au12Ag32(SR)30 NC, and is thought to constitute a guiding principle for the intelligent design of high-performance bimetallic catalysts in the future.

Improving the knowledge of the relationship between structure and properties is fundamental in catalysis. Recently, researchers have developed a variety of well-controlled methods to synthesize atomically precise metal nanoclusters (NCs). NCs have shown high catalytic activity and unique selectivity in many catalytic reactions, which are related to their ultrasmall size, abundant unsaturated active sites, and unique electronic structure different from that of traditional nanoparticles (NPs). More importantly, because of their definite structure and monodispersity, they are used as model catalysts to reveal the correlation between catalyst performance and structure at the atomic scale. Therefore, this review aims to summarize the recent progress on NCs in catalysis and provide potential theoretical guidance for the rational design of high-performance catalysts. First a brief summary of the synthetic strategies and characterization methods of NCs is provided. Then the primary focus of this review—the model ...

In catalysis, tuning the structural composition of the metal alloy is known as an efficient way to optimize the catalytic activity. This work presents the synthesis of compositional segregated six-armed PtCu nanostars via a facile solvothermal method and their distinct composition-structure-dependent performances in electrooxidation processes. The alloy is shown to have a unique six arms with a Cu-rich dodecahedral core, mainly composed of {110} facets and exhibit superior catalytic activity toward alcohols electrooxidation compared to the hollow counterpart where Cu was selectively etched. Density functional theory (DFT) calculations suggest that the formation of hydroxyl intermediate (OH*) is crucial to detoxify CO poisoning during the electrooxidation processes. The addition of Cu is found to effectively adjust the d band location of the alloy catalyst and thus enhance the formation of *OH intermediate from water splitting, which decreases the coverage of *CO intermediate. Our work demonstrates that the unique compositional anisotropy in alloy catalyst may boost their applications in electrocatalysis and provides a methodology for the design of this type catalyst.

In this work, we utilized a facile air oxidative dealloying approach to synthesize PtCu hierarchical branched nanodendrites (HBNDs). The systematical investigation on the morphology, composition, and structure of PtCu HBNDs by various techniques demonstrates they are three-dimensional open porous nanostructures. The PtCu HBNDs show composition-dependent catalysis in hydrogen evolution reaction (HER). The Pt1Cu1.03-D with average size about 40 nm composed of integrated ultrathin branches, presents the highest HER activity with only 20 mV overpotential to achieve 10 mA/cm2, 19.34 A/mgPt and 9.64 mA/cm2 in mass and specific activity at −0.2 V, and excellent durability. The superior HER activity is attributed to the unique porous dendritic structure and electronic synergistic interactions between Pt and Cu as indicated by X-ray photoelectron spectroscopy and density functional theory calculation. This work opens up a new facile route to design large accessible surface and high-performance electrocatalysts with low utilization of Pt for electrochemical energy conversion.

Atomically precise nanoclusters (NCs) have been widely used as catalysts in many reactions to investigate the structure–activity relationship due to their ultrasmall sizes, well-defined structures and precise compositions, especially bimetallic NCs can further promote the catalytic activity by the synergistic effects of heteroatoms. For electrocatalytic hydrogen evolution reaction (HER) catalysts, a common method to improve the performance is coupling with a nano-metal, but the origin of the enhancement is still unclear due to the diversity and complexity of the nanometal supported composites. Here, we take MoS2 (a star HER electrocatalyst) as an example, to report a strategy to boost the activity and give insight into the activity enhancement of it by combining with bimetallic atomically precise NCs. The crystal structure of this new NC is determined by X-ray crystallography, and its precise composition is identified as Au2Pd6S4(PPh3)4(C6H4F2S)6 (Au2Pd6 for short). The Au2Pd6/MoS2 show significantly improved HER activity and robust durability compared to the single component Pd3 or Au2/MoS2 and bare MoS2. This is attributed to the appropriate adsorption behavior of H atoms on Au2Pd6/MoS2 and the electronic interactions between NCs and MoS2, according to the combination of experiment and theory. This study presents a new strategy to improve the electrocatalytic activity of 2D materials such as MoS2 and sheds light on the origin of the promotion effects at the atomic level.

Hydrolysis reaction of ammonia borane (AB) has been considered as a safe and efficient hydrogen generation method, in which designing cost-effective and high-performance catalysts plays vital role. In this work, we have developed well dispersed palladium-nickel hollow nanospheres (PdNi HNSs) with tunable shell thickness and compositions via a facile galvanic replacement approach. The as-prepared PdNi HNSs show composition-dependent catalysis in the hydrolytic dehydrogenation of AB. The Pd84Ni16/C exhibiting sphere-shaped hollow interiors with average 70 nm particle size and 10 nm thin wall, presents the highest catalytic activity with the turnover frequency of 76.0 (mol H2 min−1 (mol Pd)−1) and the activation energy of 33.5 kJ mol−1. The superior catalytic effect of PdNi HNSs in enhancing hydrolysis efficiency of AB can be ascribed to two major factors: (1) high active surface areas of the unique hollow structure; (2) enhanced H adsorption attributed to the coupling between Pd and Ni induces polarization charges on Pd catalytic sites, which is indicated by the first-principles calculation and X-ray photoelectron spectroscopy studies. Furthermore, the catalysts exert good long-term recycling stability and catalytic activity for the hydrolytic dehydrogenation of AB. This work represents a strategy may hopefully be extended to synthesize other Pd-based hollow nanostructure with reduced Pd usage and increased catalytic active sites, and also sheds light on the exploration of utilizing interatomic interactions to regulate species adsorption/activation for highly efficient catalytic performance.

Controlled encapsulation of atomically precise nanoclusters (APNCs) into metal–organic frameworks (MOFs) has been an efficient way to create new types of multifunctional crystalline porous materials. Such hybrids (APNCs@MOFs) provide ideal candidates for studying inherent structure–catalysis relationships owing to the well-defined compositions of both components. Moreover, modeling of APNCs@MOFs with precise structures would be more reliable. Herein, we have established an “Electrostatic Attraction Strategy” to synthesize APNCs@MOF catalysts and studied their performance as catalysts for the conversion of CO2. The synthetic strategy presented here has been proved to be general, as evidenced by the syntheses of various APNCs@MOF catalysts including all the combinations of [Au12Ag32(SR)30]4−, [Ag44(SR)30]4−, and [Ag12Cu28(SR)30]4− nanoclusters with ZIF-8, ZIF-67, and MHCF frameworks. In particular, the as-obtained Au12Ag32(SR)30@ZIF-8 composite shows excellent performance in capturing CO2 and converting phenylacetylene into phenylpropiolate under mild conditions (50 °C and ambient CO2 pressure) with a TON as high as 18 164, far exceeding those of most known catalysts. What's more, the catalyst is very stable and reused 5 times without loss of catalytic activity. We anticipate that this general synthetic approach may open up a new frontier in the development of promising APNCs@MOF catalysts, which can be applied in a broad range of heterogeneous catalyses in the future.

Recently, transition metal phosphides (TMPs) have been reported as a new kind of anode catalyst for oxygen evolution reaction (OER), and the composition of the material largely determines the performance of the catalysts. However, few reports explore how electrocatalytic performance of TMPs changed with the composition of the catalysts. We selected three different component Fe-based Prussian blue analogues (PBA) as precursors and transformed them into corresponding metal phosphides by simple heat treatment. By tuning the phosphidation temperature, a series of FeCoP, FeNiP, and FeMnP were obtained, in which FeCoP under a suitable phosphidation temperature at 400 °C exhibits most obviously porous structure and broadest distribution of pore size, which benefits for the mass transfer and oxygen release during OER. Besides, the charge-transfer resistance (Rct) of TMPs has greatly decreased by introducing of Co in comparison of Ni and Mn, which accelerate the electron transport in OER. Due to the porous geometric structure and unique electronic structure, FeCoP-400 shows excellent and stable electrocatalytic activities of OER in 1 M KOH, with overpotentials of 261 mV at a current density of 10 mA cm−2, superior to commercial RuO2 and most OER electrocatalysts. Furthermore, FeCoP-400 exhibits outstanding stability with only 4% increase in potential during 24 h chronopotentiometry.