Fabrication of porous g-C3N4 and supported porous g-C3N4 by a simple precursor pretreatment strategy and their efficient visible-light photocatalytic activity

Abstract

Porous g-C3N4 and supported porous g-C3N4 were fabricated for the first time by a simple strategy using pretreated melamine as a raw material and pretreated quartz rod as a substrate. The formation of a richly porous microstructure can be attributed to the co-existence of different pore-fabricating units in the preparation system for porous g-C3N4. The richly porous microstructure endowed the as-prepared porous g-C3N4 with an excellent photocatalytic activity. The as-prepared supported porous g-C3N4 exhibited considerable stability because of the existence of chemical interaction between porous g-C3N4 and the quartz rod substrate. The photocatalytic activity of the supported porous g-C3N4 was competitive with that of porous g-C3N4 in powder form because neither the surface migration of photogenerated electrons nor the diffusion of the target organic pollutant were affected by the construction of the quartz rod reactor. The photocatalytic activity of the as-prepared porous g-C3N4 and supported porous g-C3N4 was preliminarily evaluated by the treatment of single-component organic wastewater under visible-light irradiation. Subsequently, the as-prepared porous g-C3N4 was further applied in conventional hydrogen evolution and a new system for simultaneous hydrogen evolution with organic-pollutant degradation. The hydrogen yield and degradation efficiency both increased with increasing photocatalytic activity of the as-prepared materials in the system for simultaneous hydrogen evolution with organic-pollutant degradation.