Boosting photocatalytic oxidation on graphitic carbon nitride for efficient photocatalysis by heterojunction with graphitic carbon units

Abstract

Graphitic carbon nitride has been considered as a promising metal-free visible light photocatalyst for air pollutants oxidation due to its suitable band-gap energy and higher conduction band edge. Herein, we have developed a facile approach for dramatically downwards shifting band edge positions of carbon nitride up by about 1 eV via in-plane heterojunction with graphitic carbon units to enhance the oxidation capability of the electron holes generated from the valence band. The graphitic carbon units in junction with tri-s-triazine domains were clearly observed and its in-plane hybridization with carbon nitride was formed during the copolymerization using melamine with a small amount of m-phenylenediamine as the precursors. The direct intralayer junction between the tri-s-triazine and the graphitic carbon domain, essentially different with interlayer junction reported in literature, is able to shift downwards the band edge positions via merging electron density of states of carbon nitride with that of graphitic carbon, and thus would be beneficial for separation of photoexcited charge carriers and generation of hydroxyl radicals for the oxidation of pollutants. The hybrid photocatalyst prepared with a small quantity (less than 1%) of m-phenylenediamine and melamine as precursors has shown much enhanced NO oxidation to final products(NO 2 and NO 3-) and increased NO removal 10% than the one from melamine only.

Efficient Combination of G‐C3N4 and CDs for Enhanced Photocatalytic Performance: A Review of Synthesis, Strategies, and Applications

“…Notably, as a novel kind of emerging metal-free heterogeneous photocatalyst, g-C 3 N 4 /CD composites show fascinating photocatalytic performance under visible light. [29,31,[104][105][106] To increase the absorption of visible light, separation of electron-hole pairs and photocatalytic quantum efficiency, various strategies have been developed to promote the photocatalytic activity, including morphology transformation to broaden the specific surface area, [37,41,45,97,[107][108][109] heteroatom doping to regulate energy-level configuration, [41,93,[110][111][112][113] nanoarchitectures and interface heterostructure fabrication to accelerate carriers separation, [46,100,109,[114][115][116][117][118] and so forth. These methods can partly alter the electronic structure as well as the surface properties of g-C 3 N 4 /CD, and then enhancing its photocatalytic performance.…”

“…[116] The lateral heterostructures are constructed usually through chemical bonding to join the 2D material seamlessly in-plane. [100,114,115] As is known, the interfacial design of heterostructure is pivotal factor to manipulate the catalytic kinetics in hybrid system. Comparing to the corresponding single component, the heterostructure with higher catalytic ability results from the regulative surface charge states of the catalysts, which is performed by the interfacial charge polarization for the different work functions.…”

“…Comparing to the corresponding single component, the heterostructure with higher catalytic ability results from the regulative surface charge states of the catalysts, which is performed by the interfacial charge polarization for the different work functions. [100,109,[114][115][116] Hence, the elaborate design and creation of heterostructure materials with unique architecture have been highlighted routes for boosting catalytic performances.…”

Ionic liquid‐assisted synthesis of defect‐rich BiOI with controllable structure and high surface area for excellent visible‐light photocatalytic activity

“…With the rapid development of economy and the consumption of traditional fossil fuels, environmental pollution and energy shortage have become most serious challenge. [ 1–4 ] Photocatalysis technology exhibits great promise for water splitting, CO 2 photoreduction and degradation of organic pollutants after the finding of water splitting by using TiO 2 as electrode. [ 5–8 ] Many preparation methods have been developed to fabricate novel effective photocatalysts, including element doping, heterostructure construction and morphology modification.…”

Enhanced Visible-Light Photocatalytic Activity of Ag QDs Anchored on CeO2 Nanosheets with a Carbon Coating

“…In addition, the fabrication of heterojunctions coupled with other semiconductors can simultaneously enhance the separation efficiency of charge carriers and restrain the recombination rate of photoexcited electron–hole pairs through the interface structure of different semiconductors, especially core–shell structures [42,43,44]. To further avoid photocorrosion in solar energy-driven reaction systems, carbon has been employed for the synthesis of heterojunction composites due to its unique physicochemical properties and low cost [45,46,47,48]. Carbon with a porosity structure and a high surface area not only exhibits excellent affinity for pollutant molecules, but also efficiently captures and transfers the photoexcited electron, leading to an enhancement in photocatalytic activity [49,50].…”