Photocatalytic reduction of carbon dioxide (CO) under visible light irradiation for producing high-value fuel has attracted tremendous attention in recent years. In this study, titanium carbide MXene (TiC) was used as a noble metal-free co-catalyst by simply mixing graphitic carbon nitride (g-CN) and alkalized TiC. The carbon monoxide evolution rate of the optimized composite (5%TCOH-CN) from photocatalytic reduction of CO was 5.9 times higher than that of pure g-CN. Alkalized TiC was responsible for the superior photocatalytic activity due to its excellent electrical conductivity and large CO adsorption capacity. Furthermore, the separation of the photo-induced electron-hole pairs was greatly enhanced because of the large Fermi level difference between alkalized TiC and pure g-CN. This work demonstrates the potential of MXenes as noble metal-free co-catalyst for photocatalysis processes such as carbon dioxide reduction reaction and nitrogen reduction reaction.