title: Activation of carbon nitride solids by protonation: morphology changes, enhanced ionic conductivity, and photoconduction experiments.
abstract: Covalently bonded carbon nitride materials (e.g., g-C(3)N(4)) have numerous potential applications ranging from semiconductors to fuel cells. But their solubility is poor, which makes characterization and processing difficult. Moreover, the chemistry of the as-synthesized carbon nitrides has been widely neglected. Here we report that some of these handicaps might be overcome by a controllable and reversible protonation. It was found that protonation not only provides better dispersion and exposes a high surface area for g-C(3)N(4) but also enables an adjustment of electronic band gaps and higher ionic conductivity. Recovery or deprotonation toward the original g-C(3)N(4) could be obtained by simple heating, which enables improved sintering but also a potential preservation of the higher surface area of the protonated material. This proton-enhanced sintering process allowed for the first time direct measurement of the photoconductivity of the material. By aid of protonation, other promising g-C(3)N(4) based hybrid composites could also be facilely obtained by simple counteranion exchange.
authors.affiliation: Max Planck Institute of Colloids and Interfaces, Research Campus Golm, D-14424 Potsdam, Germany.
authors.forename: Yuanjian
authors.initials: Y
authors.lastname: Zhang
authors.forename: Arne
authors.initials: A
authors.lastname: Thomas
authors.forename: Markus
authors.initials: M
authors.lastname: Antonietti
authors.forename: Xinchen
authors.initials: X
authors.lastname: Wang