Titanium dioxide (TiO₂) is a widely used photocatalyst that can oxidize motor vehicle exhaust, for example, carbon monoxide (CO), nitrogen oxides (NO_x), hydrocarbons, and sulfur dioxide, under the irradiation of sunlight. It has been reported that nano-scale TiO₂ particles can be effectively used to modify the concrete-asphalt pavement, and make it as a photocatalytic pavement. However, the pure TiO₂ additive limits its absorption spectrum to the ultraviolet region, which only occupies a small portion of sunlight irradiance. To increase the utilization of the full spectrum of sunlight, it has been demonstrated that doping TiO₂ with substances such as Carbon (C), Nitrogen (N), or metal can reduce the band-gap and extend the threshold of the absorption spectrum to the visible light region. Therefore, doped-TiO₂ has a better photocatalytic performance under sunlight irradiation. This paper conducted computational simulation of the kinetics of photocatalytic pavement to quantify the efficiency of doped-TiO₂ embedded pavement in reducing exhaust gas from motor vehicles. A three-dimensional model is developed on a section of local road with doped-TiO₂ embedded pavement. The effects of doped-TiO₂ concentration, daylight conditions, and traffic flow conditions on the removal of NO_x and CO were studied. The results indicate that the pavement with doped-TiO₂ coating is effective to remove CO and NO_x under different traffic density and daylight intensity conditions. Compared with UV activated TiO₂, visible-light-activated doped-TiO₂ features significantly higher removal efficiency of poisonous exhaustive gas including NO_x and CO.

二氧化钛（TiO ₂）是广泛使用的光催化剂，其在阳光的照射下可以氧化机动车尾气，例如一氧化碳（CO），氮氧化物（NO _x），碳氢化合物和二氧化硫。据报道，纳米级TiO ₂颗粒可有效地用于改性混凝土沥青路面，并使其成为光催化路面。然而，纯TiO ₂添加剂将其吸收光谱限制在紫外线区域，该紫外线区域仅占据一小部分阳光照射。为了提高对太阳光全光谱的利用，已证明掺杂TiO ₂碳（C），氮（N）或金属之类的物质可以减少带隙并将吸收光谱的阈值扩展到可见光区域。因此，掺杂的TiO ₂在日光照射下具有较好的光催化性能。本文对光催化路面动力学进行了计算仿真，以量化掺杂TiO ₂埋入的路面在减少机动车废气中的效率。在掺有TiO _2的人行道局部路段上建立了三维模型。掺杂-TiO 2的效果₂浓度，日光条件，和交通流量状况对去除NO的_X和CO进行了研究。结果表明，在不同的交通密度和日光强度条件下，掺杂TiO ₂涂层的路面都能有效去除CO和NO _x。与紫外线活化的TiO ₂相比，可见光活化的掺杂的TiO ₂具有明显更高的去除包括NO _x和CO在内的有毒废气的效率。