Two-dimensional Mo 2 TiC 2 MXenematerial was synthesized by etching Mo 2 TiAlC 2 and then doped into MgH 2 to tailor its hydrogen storage performance. The initial hydrogen desorption temperature of the Mo 2 TiC 2 -doped MgH 2 was significantly reduced from 330 °C (pristine MgH 2 ) to 187 °C. Isothermal dehydrogenation analysis indicated that the MgH 2 +9 wt.% Mo 2 TiC 2 composite rapidly discharged 6.4 wt.% H 2 at 300 °C within 4 min. For hydrogenation, the dehydrogenated MgH 2 +9 wt.% Mo 2 TiC 2 uptook 6.5 wt.% H 2 at 175 °Cwithin 5 min. By calculation, the activation energy for MgH 2 +9 wt.% Mo 2 TiC 2 was calculated to be (135.6±1.9) kJ/mol for the desorption reaction and (46.1±0.2) kJ/mol for the absorption reaction. After 20 cycles, 1.0 wt.% H 2 was lost for the MgH 2 +9 wt.% Mo 2 TiC 2 composite. Microstructure analysis results showed that the presence of Mo in Mo 2 TiC 2 enhanced the thermal stability of MXene and reduced the amount of active Ti during cycling, leading to poorer catalytic effect of the catalyst compared to Ti 3 C 2 .
Ge Li,Bin Zhou,Ping Wang,Miao He,Zhao Fang,Xilin Yuan,Weiwei Wang,Xiaohua Sun,Zhenxing Li
The two-electron oxygen reduction reaction (2e−ORR) pathway electrochemical synthesis to H2O2has the advantages of low investment and environmental protection and is considered to be a promising green method. Herein, the oxidized Mo2TiC2MXene (O-Mo2TiC2) was successfully synthesized by a facile hydrothermal method as an electrocatalyst in electrocatalytic H2O2production. The O-Mo2TiC2achieved the 90% of H2O2selectivity and 0.72 V vs. RHE of the onset potential. Moreover, O-Mo2TiC2showed high charge transfer ability and long-term stable working ability of 40 h. This significantly enhanced electrocatalytic H2O2production capacity is assigned the oxidation treatment of Mo2TiC2MXene to generate more oxygen-containing groups in O-Mo2TiC2. This work provides a promising catalyst candidate for the electrochemical synthesis of H2O2.Keywords:two-electron oxygen reduction reaction;electrochemical H2O2production;Mo2TiC2MXene;oxidation treatment
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