RESUMEN
Ru has recently been regarded as a promising catalyst for hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) due to its similar binding energy towards *H but lower price compared to Pt. Nevertheless, the quest of high-efficiency Ru-based catalysts for HOR and HER is driven by the current disadvantages including low activity and unsatisfactory stability. Herein, we have fabricated and engineered two-dimensional (2D) Ru-based snow-like nanosheets with Ru/RuO2 interface (Ru/RuO2 SNSs) via a post-annealing treatment. Detailed characterizations and theoretical calculations indicate that the interfacial synergy, which is dependent on the temperature for annealing, can alter the hydrogen binding energy (HBE) and hydroxide binding energy (OHBE), as a result of the enhanced HOR and HER performance. Impressively, the optimal Ru/RuO2 SNSs display a mass activity of 9.13 A mgRu-1 at an overpotential of 50 mV in 0.1 mol L-1 KOH for HOR, which is 65, 304, and 21 times higher than those of Ru SNSs (0.14 A mgRu-1), RuO2 SNSs (0.03 A mgRu-1), and commercial Pt/C (0.43 A mgRu-1), respectively. Moreover, Ru/RuO2 SNSs display improved HER activity with a low overpotential of 20.2 mV for achieving 10 mA cm-2 in 1 mol L-1 KOH. This work not only provides an efficient catalyst for HOR and HER, but also promotes fundamental research on the fabrication and modification of catalysts in heterogeneous catalysis.
RESUMEN
Amorphous materials have attracted increasing attention in diverse fields due to their unique properties, yet their controllable fabrications still remain great challenges. Here, we demonstrate a top-down strategy for the fabrications of amorphous oxides through the amorphization of hydroxides. The versatility of this strategy has been validated by the amorphizations of unitary, binary and ternary hydroxides. Detailed characterizations indicate that the amorphization process is realized by the variation of coordination environment during thermal treatment, where the M-OH octahedral structure in hydroxides evolves to M-O tetrahedral structure in amorphous oxides with the disappearance of the M-M coordination. The optimal amorphous oxide (FeCoSn(OH)6-300) exhibits superior oxygen evolution reaction (OER) activity in alkaline media, where the turnover frequency (TOF) value is 39.4 times higher than that of FeCoSn(OH)6. Moreover, the enhanced OER performance and the amorphization process are investigated with density functional theory (DFT) and molecule dynamics (MD) simulations. The reported top-down fabrication strategy for fabricating amorphous oxides, may further promote fundamental research into and practical applications of amorphous materials for catalysis.
