Study On Structure Regulation And Properties Of G-C₃N₄ Matrix Composites

Graphite phase carbon nitride（g-C₃N₄）has been developed for more than 10 years since it was proposed in the field of photocatalysis in 2009.However,g-C₃N₄ has weak carrier separation ability,and its further development is hindered by undirected migration of photocarriers.The carrier migration process is similar to electron transfer and can be regulated by microscopic electric field.Molecules with strong polarity and self-polarized ferroelectric materials are considered as ideal regulatory substances.G-C₃N₄ synthesized from different materials was prepared by secondary calcination.The specific surface area of g-C₃N₄ prepared by urea and thiourea is large,the carrier separation ability is good,and the visible light degradation time of 50 m L 5 mol/L Rh B is less than 80 min.When alkaline Na OH with strong polarity was added into the preparation of thiourea,the degradation performance of the sample under UV light was obviously improved.DCN-0.16 can degrade 90%Rh B within 20 min.After 5 cycles of use,it still retains catalytic activity and shows excellent stability.KNN powder was prepared by traditional solid-phase method,and KNN/g-C₃N₄composite photocatalyst was prepared by evaporative solvent method.The effects of optimum ratio,calcination temperature and polarization on the photocatalytic performance were investigated.When KNN mass ratio was 4%,the degradation rate was 92%in 3 h.Although the calcination temperature of the composite was adjusted to 550℃so that the catalytic degradation could be completed in 150 min,the overall photocatalytic effect still decreased.After polarization KNN doped for 90 min,the photocatalytic degradation of Rh B can reach more than 80%.The Bi₃Ti₄O₁₂ and(Bi_0.5Na_0.5)Ti O₃ fibers were synthesized with g-C₃N₄ by ultrasonic dispersion,and the piezoelectric synergistic photocatalytic properties of the samples were investigated.The composite of layered Bi₃Ti₄O₁₂ was not conducive to the visible light catalytic performance of the sample,while the incorporation of(Bi_0.5Na_0.5)Ti O₃ fiber was beneficial.Under the combined action of ultrasonic and simulated sunlight,the samples with the best ratio of the two can complete the piezoelectric co-degradation of Rh B in 40 min.Figure 57;Table 4;Reference 53...