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本文概括叙述了贮氢材料TiFeMm的贮氢特性及其表面中毒与再生机制。在贮氢材料TiFe中添加少量混合稀土金属Mm,改善了它的活化条件。我们发现,当使用98％工业纯氢气吸氢时,由于表面中毒,贮氢量下降。第一个吸放氢循环,其吸氢量下降约23％;第三个循环,其下降约61％。尽管如此,TiFeMm的抗毒性能还是比TiFe要好。中毒后的TiFeMm,经三次纯氢循环再生后,贮氢容量可回升到96％。由UPS分析表明,TiFeMm表面上过渡金属铁的d带峰强度是预测催化性质的重要依据。从AES、XPS分析结果指出,TiFeMm表面上的钛与铁分别呈TiO和金属态铁,还有少量氧与碳的表面污染。很明显,表面中毒以后,分别形成TiO_2和Fe_3O_4的表面化合物,从而抑制氢分子H_2→2H催化分裂和氢的渗透,致使贮氢量下降。从应用观点出发,我们相信,试验结果对于类似贮氢材料是很重要的。
This article summarizes the hydrogen storage characteristics of TiFeMm and its surface poisoning and regeneration mechanism. In the hydrogen storage material TiFe added a small amount of mixed rare earth metal Mm, to improve its activation conditions. We found that when 98% pure hydrogen was used for hydrogen absorption, hydrogen storage decreased due to surface poisoning. The first hydrogen absorption and desorption cycle, the hydrogen absorption decreased by about 23%; the third cycle, which dropped about 61%. Nevertheless, TiFeMm is still better than TiFe. After poisoning TiFeMm, after three pure hydrogen cycle regeneration, the hydrogen storage capacity can be recovered to 96%. The UPS analysis shows that the d-band intensity of the transition metal iron on the TiFeMm surface is an important basis for predicting the catalytic properties. From the results of AES and XPS analysis, it is pointed out that the titanium and iron on the surface of TiFeMm are in the form of TiO and metallic iron respectively, and there is also a small amount of oxygen and carbon contamination on the surface. Obviously, surface poisoning, the formation of TiO 2 and Fe 3 O 4 surface compounds, thereby inhibiting the hydrogen molecule H 2 → 2H catalytic splitting and hydrogen penetration, resulting in decreased hydrogen storage. From an application point of view, we believe the test results are important for similar hydrogen storage materials.