RESUMEN
In response to the global demand for sustainable energy solutions, the quest for stable and cost-effective hydrogen production has garnered significant attention in recent decades. Here, the emergence of layered metal phosphorus trichalcogenides (MPX3, M: transition metal, X: chalcogen) materials and their two-dimensional counterparts with customizable composition and electronic structure holds great promise for such purposes. In the present study, we successfully synthesized large-scale and high-quality FePS3, NiPS3, and an alloyed counterpart, Fe0.5Ni0.5PS3. Subsequent systematic investigations were conducted to probe their respective electronic structures and assess their hydrogen evolution reaction (HER) properties. Remarkably, our results unveiled the successful modulation of the bandgap for FexNiyPS3, ultimately bestowing it with the most favorable HER performance for Fe0.5Ni0.5PS3 when compared to the other two samples. Furthermore, our exploration into the evolution of the X-ray photoelectron spectroscopy (XPS) spectra demonstrated that the charge conversions of metal cations play a pivotal role in the HER reactions. This critical insight further enriches our understanding of the fundamental mechanisms governing the performance of the prepared layered MPX3-based electrocatalysts, thus facilitating a comprehensive and detailed analysis of the pre- and post-HER reactions. This work not only sheds light on the intricate interplay between composition, electronic structure, and catalytic performance in the realm of novel electrocatalysts, but also contributes to the broader scientific community's pursuit of sustainable and efficient hydrogen production.
RESUMEN
Direct methanol fuel cells rely on the efficiency of their anode/cathode electrocatalysts to facilitate the methanol oxidation reaction and oxygen reduction reaction, respectively. Platinum-based nanocatalysts are at the forefront due to their superior catalytic properties. However, the high-cost, scarcity, and low CO tolerance of platinum pose challenges for the scalable application of DMFCs. Herein, we report novel ultrathin ternary PtNiRu alloy nanowires to improve Pt utilization and CO tolerance. These novel electrocatalysts incorporate the oxophilic metal Ru into ultrathin PtNi nanowires, aiming to enhance the intrinsic activity of platinum while leveraging the long-term durability and high utilization efficiency provided by the bimetallic synergistic effect. The PtNiRu NWs significantly enhance both mass activity and specific activity for ORR, performing about 6.9 times and 3.9 times better than commercial Pt/C, respectively. After a rigorous durability test of 10,000 cycles, the PtNiRu NWs only exhibited a 25.2 % loss in mass activity. Additionally, for MOR, the MA and SA of PtNiRu NWs exceed that of Pt/C catalyst by 4.30 and 2.72 times, respectively, and exhibit exceptional resistance to CO poisoning. Theoretical insights from density functional theory calculations suggest that the introduction of Ru modulates the d-band center of the surface Pt atoms, which contributes to decreased binding strength of oxygenated species and an elevated dissolution potential, substantiating the enhanced performance metrics, and the durability enhancement stems from the stronger PtM bonds than those in PtNiRu NWs resulted from PtRu covalent interactions. These findings not only provide a new perspective on platinum-based nanocatalysts but also significantly advance the quest for more efficient and durable electrocatalysts for DMFCs, representing a substantial stride in fuel cell technology.