Sodium ion impregnated anatase/rutile mixed phase TiO₂ material has been synthesised by sol-gel method and characterised for understanding the solar hydrogen production activities. The presence of sodium ion can influence the crystallinity, crystallite size and photocatalytic efficiency of mixed phase TiO₂. The hydrogen evolution activities of the sodium impregnated TiO₂ and bare TiO₂ materials are compared by calculating the yield of H₂ gas evolved from the dissociation of H₂O. Even though the presence of rutile/anatase mixed phase TiO₂ is suitable for hydrogen evolution under UV/visible light irradiation, it is found that bare TiO₂ can act as a good catalyst and gives a hydrogen evolution value of 134 μmol after 5 h of irradiation from 20 mg of the catalyst. However, the sodium impregnated TiO₂ material show lower hydrogen evolution as compared to bare TiO₂ and a value of 34 μmol under similar experimental condition. The variation in hydrogen evolution may be exhibited due to high crystallinity, large crystallite size and higher percentage of the rutile phase in bare TiO₂ compared to sodium impregnated TiO₂ material. This study will be helpful for understanding the effect of alkali metal ion in metal oxide semiconductor and further understanding their detrimental effect on photocatalytic water splitting and related applications.

中文翻译：

---

钠离子浸渍对锐钛矿/金红石混合相TiO2纳米材料光催化析氢活性的影响

钠离子浸渍锐钛矿/金红石混合相TiO ₂材料已通过溶胶-凝胶法合成并表征以了解太阳能制氢活动。钠离子的存在会影响混合相TiO ₂的结晶度、晶粒尺寸和光催化效率。通过计算H ₂ O解离产生的H ₂气体的产率，比较钠浸渍的TiO ₂和裸TiO ₂材料的析氢活性。即使金红石/锐钛矿混合相TiO _{2 的}存在适用于氢气在紫外/可见光照射下的演变，发现裸 TiO ₂可以作为一种良好的催化剂，20mg 催化剂照射 5 小时后析氢值为 134 μmol。然而，与裸TiO ₂相比，钠浸渍的TiO ₂材料显示出较低的析氢并且在类似的实验条件下的值为34 μmol。由于与钠浸渍的TiO ₂材料相比，裸TiO _{2 中的}高结晶度、大晶粒尺寸和更高百分比的金红石相，可以表现出析氢的变化。该研究将有助于了解碱金属离子在金属氧化物半导体中的作用，进一步了解它们对光催化分解水及相关应用的不利影响。