RESUMEN
Traditional oxide electrocatalytic materials encounter significant challenges associated with sluggish reaction kinetics and formidable energy barriers for NH intermediates formation in electrocatalytic nitrogen fixation. The implementation of phase control emerges as an effective strategy to address these challenges. Herein, leveraging the energy localization of laser, this work achieved precise phase control of TiO2. In the optimized material system, the rutile phase TiO2 facilitates nitrogen adsorption, while the anatase phase TiO2 provides proton sources and active oxygen species. The synergistic effect of the two phases effectively enhances the electrocatalytic activity for nitrogen reduction and oxidation, with an ammonia yield reaching â¼22.3 µg h-1 cm-2 and a nitrate yield reaching â¼60.9 µg h-1 cm-2. Furthermore, a coupled dual-electrode system with mixed-phase titanium dioxide as both the anode and cathode successfully achieved a breakthrough in electrochemical overall nitrogen fixation. This laser precision control strategy for manipulating phase sites lays the groundwork for designing efficient catalysts for energy conversion and even energy storage nanomaterials.
RESUMEN
Alkaline membrane water electrolysis is a promising production technology, and advanced electrocatalyst and membrane electrode design have always been the core technology. Herein, an ion-exchange method and an environmentally friendly in situ green phosphating strategy are successively employed to fabricate Ru-Ru2 P heterogeneous nanoparticles by using hydroxyapatite (HAP) as a phosphorus source, which is an exceptionally active electrocatalyst for hydrogen evolution reaction (HER). Density functional theory calculation results reveal that strong electronic redistribution occurs at the heterointerface of Ru-Ru2 P, which modulates the electronic structure to achieve an optimized hydrogen adsorption strength. The obtained Ru-Ru2 P possesses excellent HER performance (24 mV at 10 mA cm-2 ) and robust stability (1000 mA cm-2 for 120 h) in alkaline media. Furthermore, an environmentally friendly membrane electrode with a sandwich structure is assembled by HAP nanowires as an alkaline membrane, Ru-Ru2 P as a cathodic catalyst, and NiFe-LDH as an anodic catalyst, respectively. The voltage of (-) Ru-Ru2 P || NiFe-LDH/CNTs (+) (1.53 V at 10 mA cm-2 ) is lower than that of (-) 20 wt% Pt/C || RuO2 (+) (1.60 V at 10 mA cm-2 ) for overall water splitting. Overall, the studies not only design an efficient catalyst but also provide a new route to achieve a high-stability electrolyzer for industrial H2 production.
RESUMEN
It is vitally essential to propose a novel, economical, and safe preparation method to design highly efficient electrocatalysts. Herein, phosphorus-doped iron nitride nanoparticles encapsulated by nitrogen-doped carbon nanosheets are grown directly on the iron foam substrate (P-Fe3 N@NC NSs/IF) by in situ deriving from Saccharomycetes cerevisiae (S. cerevisiae), where anion elements of C, N, and P all from S. cerevisiae replace the hazardous CH4 , NH3 , and H3 P. The diffusion pattern of N, P in S. cerevisiae and contact form between metal and S. cerevisiae observably affect the composition and phase of the product during high-temperature calcination. The obtained P-Fe3 N@NC NSs/IF demonstrates superior electrocatalytic performance for the hydrogen evolution reaction and oxygen evolution reaction, also satisfying durability. Theoretical calculation confirms that Fe sites of P-Fe3 N serve as the active center, and N sites and P doping regulate the hydrogen binding strength to enhance catalytic ability. Additionally, the two-electrode electrolyzer assembled by P-Fe3 N@NC NSs/IF as both anode and cathode electrodes needs only 1.61 V to reach 10 mA cm-2 for overall water splitting with a superb stability. The S. cerevisiae-based process presents a feasible approach for synthesis of nitrides, carbides, phosphides, and electrocatalytic applications.
