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Energy shortage and global warming caused by the extensive use of fossil fuels are urgent problems to be solved at present. Photoreduction of CO2 is considered to be a feasible solution. The ternary composite catalyst g‐C3N4/Ti3C2/MoSe2 was synthesized by hydrothermal method, and its physical and chemical properties were studied by an array of characterization and tests. In addition, the photocatalytic performance of this series of catalysts under full spectrum irradiation was also tested. It is found that the CTM‐5 sample has the best photocatalytic activity, and the yields of CO and CH4 are 29.87 and 17.94 μmol g−1 h−1, respectively. This can be ascribed to the favorable optical absorption performance of the composite catalyst in the full spectrum and the establishment of S‐scheme charge transfer channel. The formation of heterojunctions can effectively promote charge transfer. The addition of Ti3C2 materials provides plentiful active sites for CO2 reaction, and its superior electrical conductivity is also favorable for the migration of photogenerated electrons. [ABSTRACT FROM AUTHOR]

Graphite carbon nitride (g‐C3N4), as a non‐metallic photocatalyst, possesses special band structure, excellent stability and unique surface properties, which has become a focus of attention for photocatalytic application. However, pure g‐C3N4 is subject to the limit of visible light response, small specific surface area and rapid recombination of photogenerated carriers, which leads to its low photocatalytic efficiency. Due to the unique electronic structure, various quantum dots (QDs) can be applied to modify g‐C3N4 to improve the photocatalytic activity. Thus, we highlight these QDs modified g‐C3N4‐based composites by emphasizing their synthesis, their physicochemical properties as well as their photocatalytic applications in CO2 reduction, hydrogen production and pollutants degradation in this review. At last, critical summaries and some perspectives on the challenges and directions in this research field are also presented. [ABSTRACT FROM AUTHOR]

In this study, a remarkable offset deactivation effect of K and P on MnEuOx SCR catalyst has been found. Experimental results showed that the NO conversion over K−P poisoned catalyst was close to 80 % at 250 °C. Several characterization techniques containing NH3‐TPD, XPS, H2‐TPR, XRD and in situ DRIFT were used to reveal the mechanism of the offset effect. The characterization of NH3‐TPD and H2‐TPR suggested that the introduction of P on MnEuOx‐K could improve its surface acidity and redox ability. Moreover, the content of chemisorbed oxygen and Mn4+ were markedly restored under the situation that the toxic elements were coexistent on catalyst surface. The strong interaction between K and P might be the major reason for the offset deactivation effect. More specifically, PO3− species were preferentially bonded with the surface potassium species and released MnO2 active sites poisoned by K. Therefore, the highly active MnO2 sites might be protected and the catalytic activity could be restored. [ABSTRACT FROM AUTHOR]

Considering the high charge recombination rate, low optical adsorption intensity and limited active sites greatly constrict the solar‐to‐chemical conversion efficiency of polymer carbon nitride. Herein, a facile approach is reported to produce defected polymeric carbon nitride (PCN) with abundant granular bulks with fractured boundaries by thermal reduction treatment in CO atmosphere. The photocatalytic hydrogen evolution over defected PCN exhibits a rate of 3281.2 μmol g−1 h−1, 3.5 times higher than the pristine, which is most possibly ascribed to the following factors. The unique defected and porous structure not only provides higher specific surface area, more exposed active edges, abundant charge separation sites, and active centers for hydrogen generation but also is beneficial to rapid mass and charge transfer, interior diffusing of incident light, and shortening carrier transport length, thus enhancing the optical adsorption and accelerating the photocatalytic reaction kinetics. Furthermore, the electron delocalization at carbon vacancies sites on one hand facilitates the separation rate of electron–hole pairs and prolonged the carrier lifetime; on the other hand, the electronic polarization caused by C atoms loss helps increasing the affinity between catalyst and substrate reactant. Moreover, the higher electron donor density and lower conduction band minimum (CBM) potential further enhance the reduction capacity for H2 evolution. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen evolution can effectively alleviate the troublesome global energy crisis by converting solar energy into the chemical energy of hydrogen. In order to realize efficient hydrogen generation, a variety of semiconductor materials have been extensively investigated, including TiO2, CdS, g‐C3N4, metal‐organic frameworks (MOFs), and others. In recent years, to achieve higher photocatalytic performance and reach the level of large‐scale industrial applications, photocatalysts decorated with transition metal phosphides (TMPs) have shone brightly because of their low cost, stable physical and chemical properties, and substitution for precious metals of TMPs. This Review highlights the preparation methods and properties associated with photocatalysis of TMPs. Moreover, the H2 generation efficiency of photocatalysts loaded with TMPs and the roles of TMPs in catalytic systems are also studied systematically. Apart from being co‐catalysts, several TMPs can also serve as host catalysts to boost the activity of photocatalytic composites. Finally, the development prospects and challenges of TMPs are put forward, which is valuable for future researchers to expand the application of TMPs in photocatalytic directions and to develop more active photocatalytic systems. [ABSTRACT FROM AUTHOR]

CeO-CuO catalysts were prepared by citric acid method at different calcination temperatures. The purpose of this study is to investigate the influence of calcination temperature on the catalytic activity of CeO2-CuO catalyst for the selective catalytic reduction of NO with NH3. As can be seen from the results, Ce-Cu(450) is of the best low temperature selective catalytic reduction (SCR) activity among the three catalysts, which may be resulted from its large surface area, good redox ability, strong NH3 adsorption capacity, and high concentration of Cu2+ and active oxygen species on the surface. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 385-389, 2014 [ABSTRACT FROM AUTHOR]

The absorption process of NO into KMnO4/(NH4)2CO3 solutions was studied in a stirred tank reactor. The experimental results showed that the reaction process was a fast pseudo-m reaction. The reaction between NO and aqueous solutions of KMnO4/(NH4)2CO3 was found to be first-order with respect to NO and with respect to KMnO4. The frequency factor and the average activation energy of this reaction were 2.3 × 109 m3/(mol s) and 36.77 kJ/mol, respectively. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 564-568, 2013 [ABSTRACT FROM AUTHOR]

Absorption experiments of NO2 from simulated flue gas into aqueous (NH4)2SO3 solution were performed in a stirred tank reactor under atmosphere pressure. As can be seen from the experimental results, the absorption rate of NO2 into (NH4)2SO3 solution increases as the (NH4)2SO3 concentration increases from 0.01 to 0.06 mol/L. As the concentration of (NH4)2SO3 solution exceeds 0.06 mol/L, the absorption process becomes gas-film controlled. And the absorption rate increases with increasing NO2 inlet concentration but decreases with increasing reaction temperature. Compared with Na2SO3 solution, (NH4)2SO3 solution has higher NO2 absorption rate. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 465-469, 2013 [ABSTRACT FROM AUTHOR]