Enhancing the photocatalytic water splitting of graphitic carbon nitride by hollow anatase titania dielectric resonators

Graphitic carbon nitride (CN) generally needs to be exfoliated into ultrathin nanosheets to reduce photocarrier recombination. However, the exfoliation of CN into nanosheets also reduces the light absorption. How to simultaneously realize low photocarrier recombination and high light absorption remains a challenge in the practical application of CN in photocatalysis. Herein, the light absorption of CN nanosheets was enhanced by introducing hollow TiO 2 (h-TiO 2 ) dielectric resonators. The h-TiO 2 /CN heterostructures were prepared by thermally polymerizing dicyandiamide in the presence of h-TiO 2 . The electromagnetic resonances of the h-TiO 2 resonator creates strong electric field enhancement within, inside, and near external surface of the introduced h-TiO 2 nanoshells. The enhanced electric field greatly improves the light absorption of CN located in these regions. The largest hydrogen evolution rate for h-TiO 2 /CN can reach 6.3 mmol g −1 h −1 , which is over 3-fold that of pure CN (2.0 mmol g −1 h −1 ). It is also found that the small amount of CN within and inside h-TiO 2 majorly contributes to the photocatalytic performance. These findings open a new avenue by which to enhance the performance of photocatalysts and will be helpful in the design of highly efficient photocatalysts for various reactions.