Photocatalytic Air Purification Using Functional Polymeric Carbon Nitrides

Abstract

The techniques for the production of the environment have received attention because of the increasing air pollution, which results in a negative impact on the living environment of mankind. Over the decades, burgeoning interest in polymeric carbon nitride (PCN) based photocatalysts for heterogeneous catalysis of air pollutants has been witnessed, which is improved by harvesting visible light, layered/defective structures, functional groups, suitable/adjustable band positions, and existing Lewis basic sites. PCN-based photocatalytic air purification can reduce the negative impacts of the emission of air pollutants and convert the undesirable and harmful materials into value-added or nontoxic, or low-toxic chemicals. However, based on previous reports, the systematic summary and analysis of PCN-based photocatalysts in the catalytic elimination of air pollutants have not been reported. The research progress of functional PCN-based composite materials as photocatalysts for the removal of air pollutants is reviewed here. The working mechanisms of each enhancement modification are elucidated and discussed on structures (nanostructure, molecular structue, and composite) regarding their effects on light-absorption/utilization, reactant adsorption, intermediate/product desorption, charge kinetics, and reactive oxygen species production. Perspectives related to further challenges and directions as well as design strategies of PCN-based photocatalysts in the heterogeneous catalysis of air pollutants are also provided.

Functional Carbon Nitride Materials in Photo‐Fenton‐Like Catalysis for Environmental Remediation

“…[34] Moreover, CN shows remarkable chemical stability in organic solvents and under acidic/basic conditions, rendering it a robust photocatalyst. [35] Up till now, functional carbon nitride has been employed in wide solar-driven applications, such as air purification, [36,37] energy conversion [38][39][40] and storage. [41,42] For examples, CN nanosheets were used for efficient photocatalytic NO removal [36] and perovskite solar cells.…”

Porous and Few-Layer Carbon Nitride Nanosheets via Surface Steam Etching for Enhanced Photodegradation Activity

“…Developing low-cost and highly efficient photocatalysts has drawn worldwide attention because of their huge potential in environmental and energy applications. − Since the pioneering work reported in 2009 on photocatalytic hydrogen evolution over polymeric carbon nitride (PCN) by Wang et al, PCN has been considered to kick-start a new era for photocatalysts because of its metal-free, earth-abundant, visible-light response, easy design, high chemical stability, and suitable band edges for photocatalytic water splitting, carbon dioxide (CO 2 ) reduction, pollutant degradation, and other photocatalytic reactions. − Nonetheless, the pristine bulk PCN catalyst exhibits low catalytic activity because of its marginal visible absorption, inherently high exciton binding energy, and poor specific surface area; therefore, this constrains their widespread application to a certain degree. , To this end, a wide variety of tactics, including enhancing crystallinity, − constructing porous and few-layer nanosheets, − heteroatom doping, , surface modification, − heterostructure construction, , and copolymerization, − have been effectively invoked to optimize their molecular structure, electronic structure, and texture to boost their photocatalytic and electronic performances. Among them, constructing porous and few-layer PCN nanosheets may represent a valid strategy to achieve promising photocatalysts.…”

Free-standing film based on dissolution and homogeneous compounding of carbon nitride for photocatalytic sterilization

“…[7,8] The metal-free composition and photo-responsive specialty to visible light of p-CN can avoid secondary pollution, [9] caused by leaching metal ions and high energy consumption initiated by UV light source. [10][11][12] However, most applications of p-CN are in powder state [13,14] or fixed on solid substrates. [15,16] It is difficult so far to carry out the combination of p-CN with supplementary functional materials at molecular level, as the strong interlayer hydrogen bond and Van der Waals forces make it challenging to dissolve or disperse in common solvents.…”