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An electrode with low performance or limited endurance for water splitting hydrogen generation has been the key limitation for application of hydrogen in contemporary clean-energy technologies. In this paper, an Al80Ni6Co3Mn3Y5Au3 metallic glass ribbon with outstanding catalytic activity in the hydrogen evolution reaction (HER) in acidic solutions is fabricated for the first time. Its overpotential is about 70 mV @ 10 mA cm−2 and Tafel slope is about 39 mV dec−1, which are comparable to those of commercial noble Pt/C electrodes (33 mV @ 10 mA cm−2 and 38 mV dec−1). Such a high catalytic reactivity is attributed to the synergic effect of multiple elements that disperse atomically homogeneously on the nanoporous surface. The outstanding catalytic activity persists and even becomes much better over a long-time reaction, which is attributed to the formation of a protective Au-rich layer in the interface. The Al-based metallic glass ribbon is flexible with high yield strength, large elasticity and good electrical conductivity, which are desirable and promising characteristics for a free-standing catalytic electrode in the HER. [ABSTRACT FROM AUTHOR]

Controllably incorporating multiple immiscible metal elements into one single nanostructure has immeasurable technological and scientific potential, but it remains a challenge for the conventional bottom-up synthetic methods. Herein, we presented a general and scalable route to prepare multi-component nanostructured alloys referred to as nanoporous high-entropy alloys (np-HEAs) by combining bulk melting, fast cooling, and dealloying. To demonstrate this concept, we synthesized senary AlNiCuPtPdAu, octonary AlNiCuPtPdAuCoFe, and senary all-non-noble metal AlNiCuMoCoFe np-HEA with ligament sizes of ∼2–3 nm and precisely controlled composition by dealloying the designed precursor alloys. With a naturally formed thin oxide layer of spinel γ-Al2O3, AlNiCuPtPdAu np-HEA exhibited greatly enhanced high-temperature stability (up to 600 °C) and CO oxidation activity. Interestingly, with the removal of the surface oxide layer, np-HEA still showed good resistance to coarsening at 200 °C for 10 h due to its intrinsically low diffusivity originating from the multiple-principal-element mixing effect. For electrocatalysis, np-HEA with a low Pt loading amount exhibited 10 times the mass activity of Pt/C for oxygen reduction reaction and maintained 92.5% of its initial activity after 100k electrochemical cycles. [ABSTRACT FROM AUTHOR]

Monolithic 3D porous graphene with a small pore size of ∼250 nm was obtained by a chemical vapor deposition method, using dealloyed nanoporous Ni as a substrate. Monolithic nanocomposites of CoO or PdCo nanoparticles decorated on the 3D porous graphene were facilely synthesized and used as an advanced anode material for lithium ion batteries or as an electrocatalyst in fuel cells, respectively. The synthesized CoO or PdCo alloy nanoparticles with narrow diameter distributions are uniformly anchored on the porous graphene inner surface. The CoO/porous graphene nanocomposite displayed a high performance in lithium ion batteries with a large reversible capacity, excellent cycling stability, and good rate performance. The PdCo/porous graphene exhibited an enhanced catalytic activity for the oxidation of ethanol compared with both Pd/porous graphene and commercial Pd/C, highlighting the importance of monolithic porous graphene in enhancing the electrochemical performance of metal and metal oxide nanoparticles. [ABSTRACT FROM AUTHOR]

The design and fabrication of novel composite nano-architectures is crucial for their applications in energy storage devices such as lithium ion batteries (LIBs). Herein, a thin carbon nanosheet array with encapsulated hollow Co3O4 nanoparticles is successfully fabricated on 3D Ni foam by using electrodeposited Co(OH)2 nanosheets as templates and followed by a two step annealing process. When used as an anode material in LIBs, the hollow Co3O4/carbon nanosheet composite displays an excellent performance with a high reversible capacity, excellent cycling stability and rate capability. This work is helpful for the design of an advanced electrode for LIBs, supercapacitors, electrochemical sensors, etc. [ABSTRACT FROM AUTHOR]

Nanostructured high-entropy materials such as alloys, oxides, etc. , are attracting extensive attention because of their widely tunable surface electronic structure/catalytic activity through mixing different elements in one system. To further tune the catalytic performance and multifunctionality, the designed fabrication of multicomponent high-entropy nanocomposites such as high-entropy alloy@high-entropy oxides (HEA@HEO) should be very promising. In this work, we design a two-step alloying-dealloying strategy to synthesize ultra-small HEA nanoclusters (∼2 nm) loaded on nanoporous HEO nanowires, and the compositions of both the HEA and HEO can be adjusted separately. To demonstrate this concept, a seven-component HEA (PtPdAuAgCuIrRu) clusters@seven-component HEO (AlNiCoFeCrMoTi) 3 O 4 was prepared, which is highly active for both oxygen evolution and reduction reactions. Our comprehensive experimental results and first-principles density functional theory (DFT) calculations clearly show that better oxygen evolution reaction (OER) performance is obtained by optimizing the composition of the HEO support, and the seven-component HEA nanocluster is much more active for the ORR when compared with pure Pt due to the modified surface electronic structure. Specifically, the high-entropy composite exhibits an OER activity comparable to the best reported value, and the ORR activity exceeded the performance of commercial Pt/C in alkaline solutions with a record-low bifunctional Δ E of 0.61 V in 0.1 M KOH solution. This work shows an important route to prepare complex HEA@HEO nanocomposites with tuned catalytic performance for multifunctional catalysis and energy conversion., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)