Fang Liu,Jiali Wang,Wei Chen,Xiaoying Zhang,Shengting Li,Jinping Li,Yu-Fei Song,Jinfeng Chu,Guang Liu
Magnesium hydride (MgH 2 ) is broadly deemed as one of the most prospective solid-state hydrogen storage materials. However, its large-scale application is hindered by several drawbacks, including an excessive dehydrogenation temperature (>300 °C), sluggish kinetic behavior, and inevitable agglomeration and growth during cycling. To address these challenges, two-dimensional few-layered laminated titanium carbide catalyst (FL-Ti 3 C 2 T x ) was synthesized via LiF/HCl etching followed by liquid-phase ultrasonic exfoliation. These FL-Ti 3 C 2 T x nanosheets exhibit efficient catalytic activity for MgH 2 hydrogen storage. The incorporation of 5 wt% FL-Ti 3 C 2 T x significantly reduces the initial dehydrogenation temperature of MgH 2 from 325 °C to 199 °C, while enabling the dehydrogenated sample to reabsorb hydrogen at room temperature. The MgH 2 + 5 wt% FL-Ti 3 C 2 T x composite demonstrates remarkable kinetic performance, releasing 6.5 wt% H 2 within 8 min at 300 °C and uptaking 5.49 wt% H 2 within 1 min at 100 °C. Even after 50 cycles of consecutive dehydrogenation and rehydrogenation, the composite retained a hydrogen storage capacity of 6.90 wt%, corresponding to a 95.30 % capacity retention rate. Microstructure analysis and theoretical calculations reveal that the unique lamellar morphology of FL-Ti 3 C 2 T x not only provides abundant active sites and hydrogen diffusion paths, but also effectively suppresses the agglomeration and growth of Mg/MgH 2 matrix during the hydrogen absorption and desorption. More importantly, the in-situ formed Ti/TiH 2 functions as a “hydrogen pump” accelerating hydrogen diffusion, prolonging the Mg H bond length, and weakening the interaction between Mg and H. These factors synergistically enhance the absorption/desorption kinetics of MgH 2 .
Tungsten-potassium-titanium (W-K-Ti) alloys were fabricated by spark-plasma-sintering (SPS) and traditional rotary swaging (RS) techniques. Doping conditions and sintering methods were compared on the relative density, microstructure, hardness, recrystallization temperature, and the thermal shock resistance properties. Transient heat loads under 0.37 GW m −2 were applied on the W-K-Ti samples at room temperature for different cycles and pulsed durations. It was found that moderate Ti-doping (0.05 and 0.075 wt%) in W-K alloys can enhance the thermal shock resistance. Low-cycle thermal fatigue test suggested better thermal shock resistance in SPS-sintered W-K-Ti alloy (SPS-W-K-Ti) using TiH 2 dopant . The main reason was that the decomposition of TiH 2 significantly reduced the oxygen content of the ingots, which improved the ductility and thermal shock resistance of tungsten alloys . Further fracture analyses indicated that Ti-doping through TiH 2 formed intra- and inter- Ti-rich voids in TiH 2 -doped W-K alloy, while only intergranular Ti particles were found lying along grain boundaries in the Ti-doped one. The formation mechanism of the Ti-rich voids was investigated in detail. This work provides a potential route for obtaining plasma facing materials with high thermal shock resistance.
Song Wu,Junli Wang,Xuanbing Wang,Di Jiang,Jinlong Wei,Xiaoning Tong,Zhenwei Liu,Qingxiang Kong,Naixuan Zong,Ruidong Xu,Linjing Yang
s Ti-based PbO 2 electrodes must currently address the high overpotential and low corrosiveness of the anodic oxygen evolution reaction (OER) during zinc electrowinning. In this study, a composite electrode composed of Ti/TiH 2 /β-PbO 2 − Mn 3 O 4 @C (0.6 g L –1 ) was fabricated using Ti/TiH 2 generated by electrochemical reduction of Ti/TiO 2 prepared by laser ablation as an intermediate layer, co-deposited β-PbO 2 , and Mn 3 O 4 @C micro-flakes prepared by high-temperature pyrolysis-oxidation as the active layer. In a zinc electrowinning test solution (50 g L –1 ZnSO 4 mixed with 150 g L –1 H 2 SO 4 ), the oxygen evolution and corrosion behavior of the obtained Ti/TiH 2 /β-PbO 2 − Mn 3 O 4 @C composite anodes were systematically investigated. Ti/TiH 2 /β-PbO 2 − Mn 3 O 4 @C (0.6 g L –1 ) exhibited a low overpotential of 493 mV, a low Tafel slope of 73.6 mV dec −1 , a low i corr of 2.320 × 10 −5 A cm −2 and voltage stability of 1.65 V vs. RHE for up to 72 h in stability tests, with an overall performance outperformed most of the reported Ti-based PbO 2 electrode materials. The outstanding catalytic activity is primarily attributable to the low resistance and porous interlayer of TiH 2 nanosheets, which speeds up the rate of electron transfer. The addition of Mn 3 O 4 @C micro-flakes to the active layer enhances the composite electrode's OER performance and corrosion resistance.
危险品化学品经营许可证（带存储）