Titanium carbides, oxides, nitrides, and carbonitrides possess many special and excellent properties. But the high production cost caused by the traditional carbothermic reduction process severely limits the wide applications. In this study, a novel synthesis process has been proposed by reducing and carbonitriding TiO₂ with a CH₄-H₂-N₂ gas mixture at low temperatures. The synthesis of Ti(C, N, O), reaction mechanism, and the composition of the product have been investigated. Thermodynamic analysis indicated that TiO₂ could be ultimately reduced and carbonitrided to Ti(C, N, O) by CH₄-H₂-N₂ gas mixture. Based on the predictions of thermodynamics, the effects of reduction time, temperature, and gas composition have been studied experimentally. The obtained results indicated that increasing reduction temperature and introduction of N₂ are beneficial to the synthesis of Ti(C, N, O). Finally, the optimum reaction conditions have been obtained. The density functional theory (DFT) results further demonstrated the reaction mechanism. This work provides a new approach to prepare metallic carbonitrides from their oxides.

钛的碳化物、氧化物、氮化物和碳氮化物具有许多特殊和优良的性能。但传统碳热还原工艺造成的高生产成本严重限制了其广泛应用。在这项研究中，提出了一种新的合成工艺，通过在低温下用 CH ₄ -H ₂ -N ₂气体混合物还原和碳氮共渗 TiO ₂。对Ti(C,N,O)的合成、反应机理和产物组成进行了研究。热力学分析表明，TiO ₂最终可以被CH ₄ -H ₂ -N ₂还原和碳氮共渗为Ti(C, N, O)气体混合物。基于热力学的预测，实验研究了还原时间、温度和气体成分的影响。结果表明，提高还原温度和引入N ₂有利于Ti(C, N, O)的合成。最终得到了最佳反应条件。密度泛函理论（DFT）结果进一步证明了反应机理。这项工作提供了一种从氧化物制备金属碳氮化物的新方法。