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432 results on '"Zhang, Xianfa"'

45. A review of g‐C3N4‐based photocatalytic materials for photocatalytic CO2 reduction.

Author

Tang, Jing, Guo, Chuanyu, Wang, Tingting, Cheng, Xiaoli, Huo, Lihua, Zhang, Xianfa, Huang, Chaobo, Major, Zoltán, and Xu, Yingming

Subjects
CHEMICAL energy conversion, NONMETALLIC materials, PHOTOREDUCTION, CHEMICAL energy, SEMICONDUCTOR materials, NITRIDES
Abstract

Currently, the concentration of carbon dioxide (CO2) has exceeded 400 ppm in the atmosphere. Thus, there is an urgent need to explore CO2 reduction and utilization technologies. Photocatalytic technology can convert CO2 to valuable hydrocarbons (CH4, CH3OH, and C2H5OH, etc.), realizing the conversion of solar energy to chemical energy as well as solving the problems of fossil fuel shortage and global warming. Graphitic carbon nitride (g‐C3N4), as a two‐dimensional nonmetallic semiconductor material, shows great potential in the field of CO2 photoreduction due to its moderate bandgap, easy synthesis method, low cost, and visible light response properties. This review elaborates the research progress of g‐C3N4‐based photocatalysts for photocatalytic CO2 reduction. The modification strategies (e.g., morphology engineering, elemental doping, crystallinity modulation, cocatalyst modification, and constructing heterojunction) of g‐C3N4‐based photocatalysts for CO2 reduction application have been discussed in detail. Finally, the challenges and development prospects of g‐C3N4‐based photocatalytic materials for CO2 reduction are presented. [ABSTRACT FROM AUTHOR]

Published
2024
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46. Investigation of the correlation between molecular structures with high-temperature and salt resistance for acrylamides polymer in drilling fluid.

Author

Qu, Yuanzhi, Zhang, Wenchao, Ren, Han, Yuan, YueHui, Zhou, Xinyu, Yang, Gang, and Zhang, Xianfa

Subjects
DRILLING fluids, DRILLING muds, MOLECULAR structure, POLYMER clay, BENZENESULFONIC acid, POLYMERS
Abstract

Deep oil and gas are essential alternative resources for future energy sources, but the lack of high temperature and high salt resistance mechanisms and agents significantly limits their development. Copolymers of six commonly used high-temperature and salt resistance monomers and acrylamide with similar molecular weights were prepared to improve oil recovery in deep reservoirs. The effects of different functional groups on the high-temperature and salt resistance of polymers were revealed by the drilling fluid and elemental analysis, TOC test, Zeta potential, particle size, and other analytical methods. Experimental results indicate that the pyrrole ring groups, quaternary amine groups, long-chain sulfonate groups, and benzenesulfonic acid groups can effectively improve the high-temperature stability of polymers in an aqueous solution. Quaternary ammonium groups and pyrrole rings can enhance the polymer adsorption with clay under high temperatures and high salinity conditions due to charge attraction. However, these functional groups hinder the clay dispersion and reduce the stability of drilling fluids. Hydration groups, such as sulfonic and carboxylic acid groups, can better maintain the colloidal stability of drilling fluids under high temperatures and high salinity, and benzene sulfonic acid groups are the optimal hydration groups. After the polymer is adsorbed on the clay surface, the benzene sulfonic acid group assists in forming a thicker hydration film on the clay surface, effectively hindering the damage of high temperature and high salinity on the clay. The findings and observations of this study provide theoretical support for the development of high-temperature and salt resistance polymers for water-based drilling fluids of ultra-deep wells. [ABSTRACT FROM AUTHOR]

Published
2024
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