Metal-organic frameworks loaded on phosphorus-doped tubular carbon nitride for enhanced photocatalytic hydrogen production and amine oxidation.

ABSTRACT

It is still a challenge to evolve visible light photocatalysts that possess both efficient oxidation and reduction capabilities. In this paper, phosphorus-doped tubular carbon nitride@UiO-66-NH2 (p-TCN@U6-X) composites were prepared by in-situ load of UiO-66-NH2 on the surface of p-TCN based on solvothermal method, which exhibit excellent photocatalytic oxidation and reduction ability. As a result, under visible light irradiation (λ > 420 nm), the photocatalytic H2 production performance of p-TCN@U6-3 reached 2628 µmol g-1h-l, which was 8.19 and 5.36 times higher than that of p-TCN and UiO-66-NH2, respectively. Meanwhile, p-TCN@U6-3 also exhibited well selectivity rate (99%) and conversion rate (98%) for oxidative coupling of amine compounds. The high photocatalytic activities can be assigned to the improved visible light adsorption resulted from the tubular structure of p-TCN and enhanced electrical conductivity because of the phosphorus doping in p-TCN. Furthermore, UiO-66-NH2 plays the role of co-catalyst and active centers in the photocatalytic system to synergistically catalyze the reactions. Transient photocurrent spectra, steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL) further prove the more effective charge separation and transfer happened in the p-TCN@U6-X system compared with sole p-TCN and UiO-66-NH2, respectively. This work provides an effective method for creating novel carbon nitride-based photocatalytic systems with efficient capability for photocatalytic oxidation and reduction.