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High‐temperature heating is ubiquitously utilized in material synthesis and manufacturing, which often features a rapid production rate due to the significantly improved kinetics. However, current technologies generally provide overall and steady‐state heating, thereby limiting their applications in micro/nano‐manufacturing that require selective patterning and swift heating. Herein, significantly improved control over small‐scale heating is reported by utilizing 3D printed reduced‐graphene‐oxide (RGO) probe triggered by electrical Joule heating, which enables precise heating with high spatial (sub‐millimeter scale) and temporal (milliseconds) resolutions. The block copolymer‐modified aqueous‐based RGO ink enabled 3D printing of high‐precision structures, and a bio‐inspired cellular microstructure is constructed to achieve control of the electrical conductivity and maximize structure robustness (benefit for efficient heating and operability). In particular, a thermal probe featuring a microscale tip with excellent heating capabilities (up to ≈3000 K, ultra‐fast ramping rate of ≈105 K s−1, and durations in milliseconds) is fabricated. This thermal probe is ideal for surface patterning, as it is demonstrated for the selective synthesis of patterned metal (i.e., platinum and silver) nanoparticles on nano‐carbon substrates, which is not possible by traditional steady‐state heating. The material construction and heating strategy can be readily extended to a range of applications requiring precise control on high‐temperature heating. [ABSTRACT FROM AUTHOR]

Nanoparticles supported on carbonaceous substrates are promising electrocatalysts. However, achieving good stability for the electrocatalysts during long‐term operations while maintaining high activity remains a grand challenge. Herein, a highly stable and active electrocatalyst featuring high‐entropy oxide (HEO) nanoparticles uniformly dispersed on commercial carbon black is reported, which is synthesized via rapid high‐temperature heating (≈1 s, 1400 K). Notably, the HEO nanoparticles with a record‐high entropy are composed of ten metal elements (i.e., Hf, Zr, La, V, Ce, Ti, Nd, Gd, Y, and Pd). The rapid high‐temperature synthesis can tailor structural stability and avoid nanoparticle detachment or agglomeration. Meanwhile, the high‐entropy design can enhance chemical stability to prevent elemental segregation. Using oxygen reduction reaction as a model, the 10‐element HEO exhibits good activity and greatly enhances stability (i.e., 92% and 86% retention after 12 and 100 h, respectively) compared to the commercial Pd/C electrocatalyst (i.e., 76% retention after 12 h). This superior performance is attributed to the high‐entropy compositional design and synthetic approach, which offers an entropy stabilization effect and strong interfacial bonding between the nanoparticles and carbon substrate. The approach promises a viable route toward synthesizing carbon‐supported high‐entropy electrocatalysts with good stability and high activity for various applications. [ABSTRACT FROM AUTHOR]

Transition metal sulfides with a multi‐elemental nature represent a class of promising catalysts for oxygen evolution reaction (OER) owing to their good catalytic activity. However, their synthesis remains a challenge due to the thermodynamic immiscibility of the constituent multimetallic elements in a sulfide structure. Herein, for the first time the synthesis of high‐entropy metal sulfide (HEMS, i.e., (CrMnFeCoNi)Sx) solid solution nanoparticles is reported. Computational and X‐ray photoelectron spectroscopy analysis suggest that the (CrMnFeCoNi)Sx exhibits a synergistic effect among metal atoms that leads to desired electronic states to enhance OER activity. The (CrMnFeCoNi)Sx nanoparticles show one of the best activities (low overpotential 295 mV at 100 mA cm−2 in 1 m KOH solution) and good durability (only slight polarization after 10 h by chronopotentiometry) compared with their unary, binary, ternary, and quaternary sulfide counterparts. This work opens up a new synthesis paradigm for high‐entropy compound nanoparticles for highly efficient electrocatalysis applications. [ABSTRACT FROM AUTHOR]

Direct methanol fuel cells (DMFCs) are considered as a promising candidate for portable electronic devices and small electric vehicles due to their high gravimetric and volumetric energy densities. The operation of DMFCs requires efficient catalysts, especially on the anode to promote methanol oxidation reaction (MOR). To date, platinum has emerged as a chief contender for MOR. Unfortunately, most catalysts suffer from severe CO poisoning, which can passivate the catalytic surface and decrease the activity over time. Herein, a transient, thermal radiation method to synthesize ultrafine platinum nanoclusters (0.68 ± 0.13 nm) supported on carbon black (Pt NC/CB) is demonstrated. The sample demonstrates a great CO poisoning resistance and excellent activity toward MOR. The ultrafine platinum nanoclusters with increased active sites can promote the oxidation of CO at potential as low as 0.4 V. The Pt NC/CB displays an onset potential of 0.4 V and a peak current density of 1.30 mA cm−2ECSA (electrochemical active surface area), which is superior than that of reported catalysts (0.57–1.06 mA cm−2ECSA), while many of the catalysts are alloys involving noble metals. This work showcases an efficient method to prepare Pt nanoclusters with high MOR activity and great CO poisoning resistance. [ABSTRACT FROM AUTHOR]

Efficient electrocatalysts are critical in various clean energy conversion and storage systems. Polyelemental nanomaterials are attractive as multifunctional catalysts due to their wide compositions and synergistic properties. However, controlled synthesis of polyelemental nanomaterials is difficult due to their complex composition. Herein, a one‐step synthetic strategy is presented to fabricate a hierarchical polyelemental nanomaterial, which contains ultrasmall precious metal nanoparticles (IrPt, ≈5 nm) anchored on spinel‐structure transition metal oxide nanoparticles. The polyelemental nanoparticles serve as excellent bifunctional catalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The mass catalytic activity of the polyelemental nanoparticles is 7‐times higher than that of Pt in ORR and 28‐times that of Ir in OER at the same overpotentials, demonstrating the high activity of the bifunctional electrocatalyst. This outstanding performance is attributed to the controlled multiple elemental composition, mixed chemical states, and large electroactive surface area. The hierarchical nanostructure and polyelemental design of these nanoparticles offer a general and powerful alternative material for catalysis, solar cells, and more. [ABSTRACT FROM AUTHOR]

Among all the plastic pollution, straws have brought particularly intricate problems since they are single use, consumed in a large volume, cannot be recycled in most places, and can never be fully degraded. To solve this problem, replacements for plastic straws are being developed following with the global trend of plastic straw bans. Nevertheless, none of the available degradable alternatives are satisfactory due to drawbacks including poor natural degradability, high cost, low mechanical performance, and poor water stability. Here, all‐natural degradable straws are designed by hybridizing cellulose nanofibers and microfibers in a binder‐free manner. Straws are fabricated by rolling up the wet hybrid film and sealed by the internal hydrogen bonding formed among the cellulose fibers after drying. The cellulose hybrid straws show exceptional behaviors including 1) excellent mechanical performance (high tensile strength of ≈70 MPa and high ductility with a fracture strain of 12.7%), 2) sufficient hydrostability (10× wet mechanical strength compared to commercial paper straw), 3) low cost, and 4) high natural degradability. Given the low‐cost raw materials, the binder‐free hybrid design based on cellulose structure can potentially be a suitable solution to solve the environmental challenges brought by the enormous usage of plastics straws. [ABSTRACT FROM AUTHOR]