Scalable Synthesis of Accordion-Like Multilayered Titanium Nitride in Air with Enhanced Performance as Catalytic Support for Oxygen Reduction

MXenes, recognized for their potential in energy storage and conversion, face significant challenges due to severe degradation in oxidative environments, which compromises their functional properties and limits further applications. To address this issue, we have developed an efficient pathway for transforming bulk titanium nitride (TiN) into multilayered titanium nitride (M-TiN). This method integrates the intrinsic properties of MXenes with the enhanced stability of TiN, offering a viable solu-tion to the pressing issue of oxidation stability for practical applications. The synthesis of M-TiN avoids the need for inert gas protection or chemical purification steps, making the process both practical and scalable. Notably, M-TiN exhibits inherent stability and improved performance, particularly in oxygen reduction reaction (ORR) when coupled with iron phthalocyanine (FePc). The oxidized surface layer of M-TiN enhances stability in corrosive and oxidative environments and facilitates the formation of Fe-O-Ti bonds, effectively modulating the spin states of the Fe center from low spin to medium spin, thereby improving ORR performance. M-TiN/FePc also delivers a greater power density of 270.31 mW cm-2 and better cyclability than Pt/C in a zinc-air battery. The simplicity of M-TiN's synthesis, along with the inherent properties of both MXene and TiN, positions it as a promising material for the future of energy conversion and storage technologies