Environment-friendly preparation of porous graphite-phase polymeric carbon nitride using calcium carbonate as templates, and enhanced photoelectrochemical activity

Graphite-phase polymeric carbon nitride (GPPCN) is one kind of new organic semiconductor for photoelectric conversion, photocatalysis and other important catalytic reactions. However, the low surface area of bulk GPPCN limits its potential applications. Here, we report the preparation of porous GPPCN using industrially available calcium carbonate particles as the hard template; these are not only low-cost, but also easily removed by dilute hydrochloric acid. Interestingly, upon engineering the w/w ratio of template to GPPCN precursor along with the template sizes, our approach resulted in increases of about 4 and 7.5 times in the cathodic photocurrent under visible light (lambda > 420 nm) irradiation compared with bulk GPPCN when biased at -0.2 V and 0 V (vs. Ag/AgCl), respectively. These photoelectrochemical activities were higher than those of porous GPPCN obtained by all other reported techniques including the common strategy of using silica nanoparticle templates. This study opens a new avenue to explore the fascinating GPPCN materials for solar energy conversion and environmental remediation, especially for large-scale industrial applications.