Enhanced photocatalytic removal of NO_x through the synergistic effect of photothermal activation and bipyroelectricity

Photocatalysis provides a green and promising strategy for removing nitrogen oxides (NO_x), one of the main pollutants in the atmosphere. However, few studies have been able to utilize the infrared portion of sunlight due to its low energy, which accounts for >50% of the total sunlight. The conversion of infrared light into heat is an effective but flawed approach for photocatalysis, because high temperature cannot only reduce the activation barrier of the reaction and improve the migration rate of charge carriers, but also increase the collision probability of photogenerated carriers. Here, C/PVDF-BaTiO₃ (polyvinylidene fluoride, PVDF) photocatalytic films with bi-pyroelectric effect are designed to boost the full-spectrum solar photocatalytic conversion of NO_x. During the photocatalytic reaction process, the photothermal conversion of carbon and the dual pyroelectricity synergistically enhance and reinforce each other's effects. The 0.5 wt% C/PVDF-BaTiO₃ film achieves a denitrification efficiency of 60% in a flow reaction, surpassing both the BaTiO₃ and PVDF-BaTiO₃ samples by 25% and 15% respectively.