Recent Advances in Graphitic Carbon Nitride Based Electro-Catalysts for CO2 Reduction Reactions.

The electrocatalytic carbon dioxide reduction reaction is an effective means of combating the greenhouse effect caused by massive carbon dioxide emissions. Carbon nitride in the graphitic phase (g-C3N4) has excellent chemical stability and unique structural properties that allow it to be widely used in energy and materials fields. However, due to its relatively low electrical conductivity, to date, little effort has been made to summarize the application of g-C3N4 in the electrocatalytic reduction of CO2. This review focuses on the synthesis and functionalization of g-C3N4 and the recent advances of its application as a catalyst and a catalyst support in the electrocatalytic reduction of CO2. The modification of g-C3N4-based catalysts for enhanced CO2 reduction is critically reviewed. In addition, opportunities for future research on g-C3N4-based catalysts for electrocatalytic CO2 reduction are discussed.

Computational screening of effective g-C3N4 based single atom electrocatalysts for the selective conversion of CO2.

Two-dimensional (2D) material-based single-atom catalysts (SACs) have demonstrated their potential in electrochemical reduction reactions but exploring suitable 2D material-based SACs for the CO2 reduction reaction (CO2RR) by experiments is still a formidable task. In this study, theoretical screening of transition metal (TM)-doped graphitic carbon nitride (g-C3N4) materials as catalysts for the CO2RR was systematically performed based on density functional theory (DFT) calculations. An indicator for the selective formation of one carbon (C1) products was developed to screen catalysts that are active and selective in the CO2RR. The results indicated that Ti- and Ag-g-C3N4 demonstrate excellent catalytic activity and selectivity for the formation of CO and HCOOH, with limiting potentials of -0.330 and -0.096 V, respectively, while Cr-g-C3N4 exhibits the highest catalytic activity for yielding CH3OH and CH4 (-0.355 and -0.420 V, respectively), but none of the screened catalysts have been identified as ideal candidates for the selective production of CH3OH and CH4. Furthermore, Bader charge analysis suggested that excessive electron transfer from TM leads to stronger adsorption of intermediates and high limiting potentials, which subsequently result in lower catalytic activity. This work provides theoretical insights into the effective screening of active and selective 2D material-based SACs which has the potential to significantly reduce the time and resources required for the discovery of novel electrocatalysts for the controlled formation of various products.

Adsorptive removal of organic dyes via porous materials for wastewater treatment in recent decades: A review on species, mechanisms and perspectives.

Organic dyes, a type of high toxic and carcinogenic chemicals that present severe threats to human and aquatic life, are the most commonly seen organic pollutants in wastewater of industries such as textile, rubber, cosmetic industry etc. Various techniques for the removal of dyes are compared in this review. Adsorption has proven to be a facile and promising approach for the removal of dyes in wastewater. This work focuses on the latest development of various porous materials for the adsorption of organic dyes. The characteristics, functionalization and modification of different porous materials are also presented. Furthermore, adsorption behaviors and mechanism of these adsorbents in the adsorption of organic dyes are critically reviewed. Finally, challenges and opportunities for future research in the development of novel materials for the highly efficient removal of dyes are proposed.