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Pd3Pt1 is identified with high selectivity (low aromatic depletion), while Pd1Pt1 and Pd1Pt3 are more active for olefin hydrogenation. The PdPt alloys present superior sulfur tolerance compared to Pd.

Regulating catalyst composition is one of the efficient approaches to boost intrinsic activity of electrocatalysts for water splitting. Herein, four different hollow porous platinum-copper (PtCu) nanotubes (NTs) with controllable compositions were precisely fabricated by a facile wet-chemistry method. Importantly, Pt

Constructing highly active, durable, and cost-effective catalysts is urgent for green hydrogen production. Herein, high density Pt (24 atoms nm -2 ) and Ir (32 atoms nm -2 ) single atoms anchored on Co(OH) 2 were successfully constructed by a facile one-step approach. Remarkably, Pt 1 /Co(OH) 2 and Ir 1 /Co(OH) 2 only afforded 4 and 178 mV at 10 mA cm -2 for hydrogen evolution reaction and oxygen evolution reaction, respectively, closing to the world record level. Moreover, assembled Pt 1 /Co(OH) 2 // Ir 1 /Co(OH) 2 system showed mass activity of 4.9 A mg noble metal -1 at 2.0 V in flowing alkali water electrolyzer, which is 316.1 times higher than that of Pt/C // IrO 2 . Mechanism studies revealed reconstructed Ir-O 6 single atoms and remodeled Pt triple-atom sites largely enhance the occupancy of Ir-O bonding orbitals and improve the occupation of Pt-H antibonding orbital, respectively, contributing to the formation of O-O bond and the desorption of hydrogen. This one-step approach was also generalized to fabricate other 20 kinds of single-atom catalysts.

Ag-based catalysts have been used in many practical reactions, such as p-nitrophenol reduction, due to the advantages of low cost and excellent activity. In order to facilitate the development of Ag-based catalysts, it may be helpful to use automated equipment for experiments. In this study, a system for the high-throughput synthesis of Ag-based catalysts was developed based on a facile impregnation method. Notably, the system automates the batch synthesis of Ag-based catalysts by setting the catalyst formulation in a dedicated software. Moreover, the software used employs the ant colony algorithm to optimize the synthesis path and improve the synthesis efficiency. The catalysts obtained from the high-throughput system are found to be similar to the manually prepared samples based on comparison of characterization results. In addition, experiments also reveal that this high-throughput system is capable of achieving high-throughput synthesis of Ag-based catalysts at the gram level. The synthesis of Pt–Ag bimetallic catalysts shows that this high-throughput system can be effectively used for exploratory experiments. This work paves the way for a high-throughput technique to synthesize Ag-based catalysts in a short period of time, which could be extended to the preparation of other catalyst systems. Moreover, the high-throughput synthesis system of Ag-based catalysts provides a feasible prerequisite for subsequent high-throughput characterization, which is a significant advancement in the development of industrial catalysts.

Structure is the key to understanding the properties of metal nanoclusters. Finding a globally optimal structure on an extremely complex potential energy surface is a great challenge for theoretica...

Alloying is an effective approach to improve the catalysis performance of Pd-based catalysts for the selective hydrogenation of diolefins towards monoolefines. Herein, PdAgCu ternary nanoalloy catalysts were synthesised by a stepwise impregnation method for isoprene selective hydrogenation. The addition of a moderate amount of Ag and Cu to Pd significantly enhances the isoamylene selectivity in the isoprene hydrogenation, and decreases the non-desired over-hydrogenation. In addition, the loading molar ratio of PdAgCu with 3 : 2 : 3 as the optimal ternary nanoalloy composition maximizes the isoprene conversion (98%) and the monoolefins yield (92%). The surface structure of the catalyst was probed using H

Herein, atomic Ru doped ultra-thin Co(OH)2 nanosheet arrays are firstly synthesized by a one-step electrochemical deposition method. Importantly, the obtained electrocatalyst can display excellent activity for oxygen evolution reaction, which only needs 305 mV at 50 mA cm−2 in 1 M KOH and 261 mV at 10 mA cm−2 in 0.1 M KOH. Further mechanism studies disclose that the doping of Ru could reduce the thickness of nanosheets and contribute to the generation of active Co3+ sites by donating electrons from Co to Ru atoms via the Co–O–Ru bonds. This work paves a simple method to fabricate Co based nanosheet catalyst, which may be extended to the preparation of other highly active electrocatalysts.

Fe-N-C with atomically dispersed Fe single atoms is the most promising candidate to replace platinum for the oxygen reduction reaction (ORR) in fuel cells. However, the conventional synthesis procedures require quantities solvents and metal precursors, sluggish adsorption process, and tedious washing, resulting in limited metal doping and uneconomical for large-scale production. For the first time, Fe2O3 is adopted as the Fe precursor to derive abundant single Fe atoms dispersed on carbon surfaces. The Fe-N-C catalyst synthesized by this simple method shows an excellent ORR activity with half-wave potentials of 0.82 and 0.90 V in acidic and alkaline solutions, respectively. A single fuel cell with an optimized Fe-N-C cathode shows a high peak power density of 0.84 W cm-2. The solid-state transformation synthesis method developed in this study may shed light on mass production of single-atom-based catalysts.

The pristine transition metals (TMs) offer limited choices for high-performance heterogeneous catalysts because they are usually restricted in less optimal regions on the reactivity volcano map. Us...

In recent years, atomically dispersed metal catalysts with well‐defined structures have attracted great interest in heterogeneous catalysis due to their high atomic utilization efficiency, activity, stability, and selectivity. The rapid development of single‐atom catalysts (SACs) has simultaneously stimulated the emergence of diatomic catalysts (DACs) and single cluster catalysts (SCCs). Compared with SACs, DACs, and SCCs possess higher metal loading and more structurally flexible active sites, which provide great potential for achieving higher catalytic performance. DACs and SCCs have become a new field of heterogeneous catalysis. In this review, we first focus on the latest developments of DACs/SCCs, including synthesis methods and characterization approaches including experimental and theoretical tools. In addition, the relationship between structure and catalytic performance of DACs/SCCs are well discussed, including the effect of supports, synergistic metal atoms, and coordination environment. At last, the similarities and differences between SACs and DACs/SCCs are systematically summarized and analyzed.

The controlled oxidation of alcohols to the corresponding ketones or aldehydes via selective cleavage of the β-C-H bond of alcohols under mild conditions still remains a significant challenge. Although the metal/oxide interface is highly active and selective, the interfacial sites fall far behind the demand, due to the large and thick support. Herein, we successfully develop a unique Au-CuO Janus structure (average particle size=3.8 nm) with an ultrathin CuO layer (0.5 nm thickness) via a bimetal in situ activation and separation strategy. The resulting Au-CuO interfacial sites prominently enhance isopropanol adsorption and decrease the energy barrier of β-C-H bond scission from 1.44 to 0.01 eV due to the strong affinity between the O atom of CuO and the H atom of isopropanol, compared with Au sites alone, thereby achieving ultrahigh acetone selectivity (99.3 %) over 1.1 wt % AuCu

The introduction of anti-triangular dots by etching MoS2 has been recently reported as an efficient way to produce active internal edges. However, it is still ambiguous to identify the configuration of etched MoS2 with comparative hydrogen evolution reaction (HER) activity to commercial Pt. In this work, the HER activity on etched anti-triangular MoS2 are investigated by density functional theory calculations. We found the valence electron distribution of inner edge atoms can be affected by the corner, and accordingly determine their activity. The second-nearest atom to anti-triangular corner possesses the highest activity. The simulated polarization curves show etched anti-triangular Mo-edge MoS2 with moderate size (around 12 A) maximize the HER performance. Further increasing size of etched MoS2 deactivate their HER activity to a certain degree, validated by available experimental data. This work suggests etched MoS2 catalysts with rational design may be a candidate to substitute Pt electrodes as HER electrocatalyst.

Over the past decade, the first-principles-aided thermodynamic models have become standard theoretical tools in research on structural stability and evolution of transition-metal heterogeneous catalysts under reaction environment. Advances in first-principles-aided thermodynamic models mean it is now possible to enable the operando computational modeling, which provides a deep insight into mechanism behind structural stability and evolution, and paves the way for high-through screening for promising transition-metal heterogeneous catalysts. Here, we briefly review the framework and foundation of first-principles-aided thermodynamic models and highlight its contribution to stability analysis on catalysts and identification of reaction-induced structural evolution of catalyst under reaction environment. The present review is helpful for understanding the ongoing developments of first-principles-aided thermodynamic models, which can be employed to screen high-stability catalysts and predict their structural reconstruction in future rational catalyst design.

Alloying is a viable approach to altering the local and overall structure of metallic nanocatalysts, thereby offering new possibilities to tune catalytic activities and selectivity of alloy nanoclu...

Developing highly active and durable electrocatalysts with low levels of Pt content toward some crucial reactions including oxygen reduction reaction, hydrogen evolution reaction, and methanol oxidation reaction in an acidic electrolyte environment are desirable but still an open challenge for clean and efficient energy conversion. Herein, we present a facile route to synthesize low Pt-content ternary PtNiCu nanostructures with hollow interior and accessible surfaces (H-PtNiCu-AAT NPs) as enhanced multifunctional electrocatalysts. The galvanic replacement reaction and atomic diffusion between in situ preformed CuNi nanocrystals and Pt species should be responsible for the formation of hollow PtNiCu NPs. Continuous activation by acid picking and annealing treatments were performed to leach out the excessive Cu and Ni on the surfaces and to enrich Pt-content on the surface. H-PtNiCu-AAT NPs exhibit excellent activity and durability toward HER, ORR, and MOR due to the rational integration of multiple structural advantages. Strikingly, the mass activity and specific activity of H-PtNiCu-AAT NPs (0.977 A mg

Developing active and durable electrocatalysts for oxygen reduction reaction (ORR) is of great significance in proton exchange membrane fuel cells (PEMFCs). Herein, we develop a facile strategy to synthesize PtCu nanoparticles with enhanced ORR performance through morphology tuning and transition-metal doping. Two distinct PtCu nanoparticles, namely nanooctahedrons (NOs) and nanospheres (NSs), are selectively synthesized in presence or absence of W(CO)6 via a facile one-pot method. Furthermore, by introducing a small amount of third transition metal, M-doped (M = Sc, Y, La, Gd, Fe) PtCu NOs are obtained. Electrocatalytic results suggest that the ORR performance of PtCu NOs is better than that of PtCu NSs due to the morphology advantages. And the ORR performance of PtCuM NOs is further promoted since the doping effect of transition metals compared to that of PtCu NOs. Particularly, PtCuSc NOs exhibit remarkable mass activity (1.652 mA μg−1Pt) and specific activity (2.093 mA cm−2), which are 9.9 and 7.2 times higher than that of commercial Pt/C catalysts at 0.8 V (vs. RHE). Moreover, after accelerated stability tests, the loss of mass activity for PtCuSc NOs is only 9.2%, which is much lower than that of PtCu NOs (16.5%) and commercial Pt/C (44.3%). This work provides a feasible idea to boost the ORR performances of Pt-based nanoparticles.

Pt-based cluster have received much attention for their catalytic applications, while its stability property and phase diagram remain unclear. In this work, the structural, thermal and phase stability of Pt–Cu nanoclusters, with various atomic arrangement, morphologies and sizes, are studied by both atomistic simulations and theoretical model. Pt atoms tend to distribute around the surface and Cu atoms prefer occupying inner core, derived from the surface energies, lattice parameters and the binding energy of the metal bond. Furthermore, we focus on the melting points and phase diagrams of Pt–Cu nanoalloys with different morphologies and sizes. The melting point of Pt–Cu nanoparticles rises with the increasing size. The distribution of Pt atoms along surface enhances the structural and thermal stability of the Pt–Cu nanoalloys. This theoretical work serve as a case to explore the stability and segregation properties of nanoalloys by combining atomistic simulations and theoretical model, which provides a deep insight into the effect on the stability and segregation properties of bimetallic nanoparticles.

Herein, we introduce a facile strategy for the structure-controlled synthesis of one-dimensional PdCu nanocrystals via a seed-mediated approach. This developed strategy involves the synthesis of Cu nanowires with penta-twinned structure, and subsequent growth of Pd metal on Cu nanowires. The obtained one-dimensional PdCu nanocrystals are of rough surfaces and core-shell like architecture. Upon the tuning reactivity of (111) and (100) crystal faces on Cu nanowires in absence or presence of capping agent, one-dimensional PdCu nanocrystals with solid or hollow interiors (nanowires or nanotubes) can be controllably synthesized through galvanic displacement reaction, respectively. It is found that both PdCu nanowires and PdCu nanotubes exhibit better performance for oxygen reduction reaction compared with self-synthesized PdCu nanoparticles and commercial Pd/C in 0.1 M KOH electrolyte. Particularly, PdCu nanotubes show Pt-like performance, and achieve an onset potential of 0.941 V ( vs. RHE) and a half potential of 0.825 V. The electron transfer number during oxygen reduction is close to 4 on PdCu nanotubes. Moreover, the catalytic stability of the obtained one-dimensional PdCu nanocrystals is much superior to that of commercial Pd/C and Pt/C catalysts.

The purpose of this paper is to revisit the role of a Cl promoter in selectivity enhancement of ethylene epoxidation by a combined density functional theory and experimental study. The paper argues...

Pyrolysis gasoline is applied to extract aromatics and to be gasoline blending stock, and its stabilization by catalytic hydrogenation under mild temperature is an important reaction in petrochemical field. Thereinto, styrene hydrogenation was considered as an example for the assessment of the catalysis performance for pyrolysis gasoline hydrogenation. In this work, the adsorption and diffusion of reactants (styrene and H) and the activation energy of styrene hydrogenation on Pd(111), Pd(100), and Pd(110) surfaces are discussed by density functional theory calculations. The adsorption energy of reactants (styrene and H) decreases in the order of Pd(110) > Pd(111) > Pd(100). The activation barriers with feasible intermediate products are investigated and the reaction activity based on the activation barriers follows the order of Pd(111) > Pd(100) > Pd(110). In addition, the diffusion barrier for styrene or H is smaller than the reaction barrier of styrene hydrogenation, indicating the true rate limiting step is the process of hydrogenation rather than the diffusion. Our results provide theoretical guide for the prepared catalyst with feasible surfaces by careful selection of preparation techniques in experiments.