A facile ultrasonication‐assisted wet chemistry method for preparing multicomponent alloy nanoparticles (NPs) including high‐entropy alloys (HEAs) is reported. PtAuPdRhRu alloy (HEA), quaternary PtAuPdRh alloy, and ternary PtAuPd alloy NPs are produced with ≈3 nm in diameter. Taking advantage of the acoustic cavitation phenomenon in ultrasonication process, noble metal precursors could be co‐reduced by chemical reductants and transform to alloy structures under operation at room conditions. The instantaneous massive energy (≈5000 °C, 2000 atm) occurring in momentary timespans (≤10−9 s) contributes to the formation of multimetallic mixed nanomaterials driven by entropy maximization. Owing to strong synergistic effects, the catalysts with the HEA NPs supported on carbons exhibit prominent electrocatalytic activities for hydrogen evolution reaction.

In the present study,asonochemical-based method for onepot synthesis of entropy-stabilized perovskite oxide nanoparticle catalysts with high surface area was developed. The highentropyp erovskite oxidesw ere synthesized as monodispersed, spherical nanoparticles with an average crystallite sizeo fa pproximately 5.9 nm. Ta king advantage of the acoustic cavitation phenomenon in theu ltrasonication process, BaSr(ZrHf-Ti)O 3 ,B aSrBi(ZrHfTiFe)O 3 and Ru/BaSrBi(ZrHfTiFe)O 3 nanoparticles were crystallized as single-phase perovskite structures through ultrasonication exposure withoutc alcination. Notably, the entropically-driven stability of Ru/BaSrBi(ZrHfTiFe)O 3 with excellent dispersion of Ru in the perovskite phase bestowed the nanoparticles of Ru/BaSrBi(ZrHfTiFe)O 3 with good catalytic activity for CO oxidation.As ignificant breakthrough in multicomponent alloy systems has inspired the exploration of the vast compositional space offered by high-entropy materials (HEMs). [1][2][3][4][5][6] HEMs are based on the premise of incorporatingm ultiple components (usually five or more) into as ingle crystal phase to attain unique combination of properties that are otherwise unattainable in conventional solid solutions. [7] Amongt his novel class of crystalline materials, high-entropy alloys were first reported in 2004 by the independentp ioneering works of Cantor et al. and Yeh et al. [5,6] Recent studies have extended the high-entropy concept to include the ionic compounds, in which five or more metallice lements have been used to populate as inglec ation sublattice to introduce highc onfigurational entropyi nto the crystal structure. Examples include high-entropy metal dibor-ides, [4] high-entropy nitrides, [8,9] and high-entropy metal oxides (HEMOs). [10] More recently,J iang et al. extended the HEMO study to include perovskite-type oxides with six and seven metallice lements. [11] The synthesis involved blending and ball millingo fs toichiometric amounts of the corresponding metaloxide precursors for approximately 6h and subsequentc alcination at temperatures above 1300 8Ct of orm the high-entropy perovskite oxide (HEPO) ceramics. Although the particle size distribution of the synthesized perovskites was not reported, several studies have demonstrated that such extreme temperatured uring the synthetic process causes coagulation of grain boundaries, leadingt ot he formation of clumps, and consequent reduction in the available surfacea rea for reactions. [10,12,13] Although conventional perovskites with high-surface area have been synthesized previously, [14,15] high-entropy perovskites with high surfacearea have not been reported previously to the best of our knowledge.Perovskites are an important class of materials that exhibit a wide range of functionality,m aking them desirable for use in different areas of application including heterogenous catalysis. [16] In 1975, Gallagher et al. reported the use of perovskites as potentialr eplacement for noble-metal-based catalystsi na utomotive exhaust systems. [17] The initia...

Tuning the atomic interface configuration of noble metals (NMs) and transition-metal oxides is an effective straightforward yet challenging strategy to modulate the activity and stability of heterogeneous catalysts. Herein, Pd supported on mesoporous Fe2O3 with a high specific surface area was rationally designed and chosen to construct the Pd/iron oxide interface. As a versatile model, the physicochemical environments of Pd nanoparticles (NPs) could be precisely controlled by taming the reduction temperature. The experimental and density functional theory calculation results unveiled that the catalyst in the support–metal interface confinement (SMIC) state showed significantly enhanced catalytic activity and sintering resistance for CO oxidation. The constructed Fe sites at the interfaces between FeO x overlayers and Pd NPs not only provided additional coordinative unsaturated ferrous sites for the adsorption and activation of O2, thereby facilitating the activation efficiency of O2, but also impressively changed the reaction pathway of CO oxidation. As a result, the catalyst followed the Pd/Fe dual-site mechanism instead of the classical Mars–van Krevelen mechanism. For the catalyst in the strong metal–support interaction (SMSI) state, its catalytic activity was seriously suppressed because of the excessive encapsulation of the active Pd sites by FeO x overlayers. The present study therefore provides detailed insights into the SMIC and SMSI in ferric oxide-supported Pd catalysts, which could guide the preparation of highly efficient supported catalysts for practical applications.

Porous carbon spheres derived from polymer colloids with regular geometry, monodispersed morphology, well-controlled contents and structures play important roles in many areas of application, such as energy storage/conversion, gas adsorption/separation, catalysis, and chemo-photothermal therapy. Suitable polymerization reaction and synthetic strategy are both critical for the obtainment of stable polymer colloids as carbon precursors. Basic polymerization reactions are the cornerstones of synthetic strategies, which directly provides the direct molecular-based design of functionalized polymer/ carbon spheres. Thus, this progress report mainly focuses on the summary of suitable polymerization reactions for colloidal polymer derived porous carbon spheres. Recent advances in the synthetic strategies and applications are also discussed, including their corresponding polymerization reactions. Finally, the perspectives for the development of polymer derived porous carbon spheres are provided based on the controlled synthesis of polymer colloids and optimization over the carbonization process to achieve highly functionalized carbon spheres for practical applications. 2002475 (2 of 21) www.advmat.de www.advancedsciencenews.com Sheng Dai obtained his B.Sc. degree (1984) and M.Sc. degree (1986) in chemistry from Zhejiang University, Hangzhou, China, and his Ph.D.