Cubic boron nitride (cBN), a typical superhard material, has garnered significant interest for both fundamental scientific research and technical applications. Here, nanostructured cBN with high-density nanotwins and stacking faults was synthesized by rapid quenching using hexagonal boron nitride (hBN) as the starting material at a moderate temperature (2200 K) and low pressure (13 GPa). This synthetic nanostructured cBN exhibits high Vickers hardness (78 GPa), high fracture toughness (11.8 MPa·m 1/2 ), and extremely high oxidization temperature (1565 K). We propose that the refined grain structure and excellent mechanical properties of the cBN synthesized in this study is attributed mainly to dislocation slips and (111) mechanical nanotwins that dominate this phase transformation.
The development of transition metal oxides (TMOs) as electrocatalysts for oxygen evolution reaction (OER) has the potential to surpass the performance of noble-metal-based catalysts. In this work, a quenching rapidly strategy was used to synthesize Mo-modified Co3O4 nanosheet arrays as advanced catalysts. The resulting Mo-Co3O4 electrodes showed superior activity and reaction kinetics, with an overpotential of only 341 mV to drive a current density of 100 mA cm−2 and a Tafel slope of 69.0 mV dec−1. This improved performance is thought to be due to the formation of high-valence Co sites, which creates a synergistic effect. The ability to regulate the synthesis without causing obvious agglomeration and nucleation growth during annealing makes this method a promising approach for the design of other advanced functional materials.
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