Sodium alanate, NaAlH, has great potential as a hydrogen carrier but suffers from sluggish kinetics and poor reversibility caused by high energy barriers. Transition metal-based catalysts are especially effective in reducing kinetic energy barriers for hydrogen cycling of NaAlH. Herein, we demonstrate a facile fabrication of TiC nanoparticles with 2–4 nm in size supported on carbon (nano-TiC@C). The resultant product consists of approximately 49.2 wt% of TiC and 50.8 wt% of C, and exhibits high and stable catalytic activity for hydrogen storage process of NaAlH. The 7 wt% nano-TiC@C-containing NaAlH releases 5 wt% H starting from 65 °C and reabsorbs all released hydrogen at 30 °C under 100 bar H, outperforming NaAlH modified by commercial TiC nanoparticles (∼50 nm in size). The enhancement is related to the ultrasmall size and high reactive activity of as-synthesized TiC nanoparticles. Moreover, the weak electronegativity of C prevents the formation of Na-based by-products, which are often observed in oxide and halide-containing systems. This finding sheds light on how to design and synthesize high-performance catalytic additives for light-metal hydride-based hydrogen storage materials.

中文翻译：

---

氢辅助一锅合成超小 TiC 纳米颗粒增强铝氢化钠的氢循环


铝氢化钠（NaAlH）作为氢载体具有巨大的潜力，但由于高能垒而导致动力学缓慢和可逆性差。过渡金属基催化剂在降低 NaAlH 氢循环的动能垒方面特别有效。在此，我们展示了碳支撑的尺寸为 2-4 nm 的 TiC 纳米粒子（纳米 TiC@C）的简便制造方法。所得产物由约 49.2 wt% 的 TiC 和 50.8 wt% 的 C 组成，对 NaAlH 储氢过程表现出高且稳定的催化活性。含有 7 wt% 纳米 TiC@C 的 NaAlH 从 65 °C 开始释放 5 wt% H，并在 30 °C、100 bar H 下重新吸收所有释放的氢，优于商用 TiC 纳米粒子（尺寸约 50 nm）改性的 NaAlH。 。这种增强与合成的 TiC 纳米粒子的超小尺寸和高反应活性有关。此外，C的弱电负性阻止了钠基副产物的形成，这种副产物经常在含氧化物和卤化物的体系中观察到。这一发现揭示了如何设计和合成用于轻金属氢化物基储氢材料的高性能催化添加剂。