Confined reaction inside nanotubes： New approach to mesoporous g-C3N4 photocatalysts

Mesoporous g-C3N4 nanorods （NRs） are synthesized through the nano-confined thermal condensation of cyanamide in silica nanotubes （NTs） with porous shells.The gas bubbles retained during condensation and the limited cyanamide precursor inside the silica NTs lead to the formation of mesoporous g-C3N4.This nano-confined reaction is an alternative method to the traditional templating process for the synthesis of mesoporous materials.The as-prepared mesoporous g-C3N4 NRs exhibit remarkably improved photocatalytic activity and high stability in water splitting and degradation of Rhodamine B compared with bulk g-C3N4.

Fly ash-based geopolymer as a novel photocatalyst for degradation of dye from wastewater

The geopolymer synthesized by alkali-activated fly ash was firstly used as a novel photocatalyst for degradation of methylene blue （MB） dye from wastewater. The geopolymer is composed of nanoparticulates with an average particle size of about 50 nm, More than 90% of pore volume in the fly ash-based geopolymet predominately centralized on the pore size in the range of 17-700 nm. The degradation efficiency of MB dye by fly ash-based geopolymer catalyst was up to 92.79% under UV irradiation due to the synergistic effect of adsorption and semiconductor photocatalysis. The pseudo-first-order and pseudo-second-order rate equations as well as intra-particle diffusion rate equation were employed to correlate analysis for the adsorption kinetics of MB dye, The experimental data agreed well with pseudo-second-order rate equation in both cases of with UV and without UV irradiations. The intra-particle diffusion process is not the rate determining step. The photocatalytic degradation of MB dye in solution obeys third-order reaction kinetics.