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How to overcome strength-electrical conductivity trade-off is essential for functional and structural applications of Cu matrix composites. Here we propose a new dispersion and strengthening strategy to prepare graphene/Cu matrix composites. The graphene reinforcements are in situ exfoliated from graphite flakes through plasma assisted ball milling, and are intra-/inter-granularly dispersed in the Cu matrix after hot-rolling process. The graphene/Cu matrix composite has high tensile strength up to ∼497 MPa and electrical conductivity of 84.2% IACS, contributed by intra-/inter-granular graphene with average size of about 22 nm and 132 nm, respectively. In-situ electron microscopy and molecular dynamic simulation are performed to investigate deformation behavior of the composites, revealing that interaction between intra-/inter-granular graphene and dislocations effectively increase dislocation storage ability. This work offers a general pathway for fabricating graphene/Cu matrix composite with well-balanced strength and electrical conductivity.

Pt-based high-entropy-alloy nanoparticles (HEA-NPs) have excellent physical and chemical properties due to the diversity of composition, complexity of surface structure, high mixing entropy, and properties of nanoscale, and they are used in a wide range of catalytic applications such as catalytic ammoxidation, the electrolysis of water to produce hydrogen, CO2/CO reduction, and ethanol/methanol oxidation reaction. However, offering a facile, low-cost, and large-scale method for preparing Pt-based HEA-NPs still faces great challenges. In this study, we employed a spray drying technique combined with thermal decomposition reduction (SD-TDR) method to synthesize a single-phase solid solution from binary nanoparticles to denary Pt-based HEA-NPs containing 10 dissimilar elements loaded on carbon supports in an H2atmosphere with a moderate heating rate (3 °C/min), thermal decomposition temperature (300–850 °C), duration time (30 min), and low cooling rate (5–10 °C/min). The Pt autocatalytic behavior was found and investigated, confirming that Pt element could decrease the reduction temperature of other metals via autocatalytic behavior. Therefore, using the feature of Pt autocatalytic behavior, we have achieved Pt-based HEA-NPs at a minimum temperature of 300 °C. We not only prepared a series of Pt-based HEA-NPs with targetable ingredient, size, and phase using the SD-TDR method but also proved the expandability of the SD-TDR technique by synthesizing Pt-based HEA-NPs loaded on different supports. Moreover, we investigated methanol oxidation reaction (MOR) on as-synthesized senary PtCoCuRuFeNi HEA-NPs, which presented superior electrocatalytic performance over commercial Pt/C catalyst.