Fumaric Acid Assistant Band Structure Tunable Nitrogen Defective g-C₃N₄ Fabrication for Enhanced Photocatalytic Hydrogen Evolution

Abstract

Tuning the structural defects of graphite carbon nitride (g-C3N4) is an effective strategy to modify its band structure and promote charge separation, but it is still limited by complex and harsh preparation processes. Herein, g-C3N4 with nitrogen defects were fabricated by one-pot thermal polymerization of urea and fumaric acid. The N–(C)3 site, being the active site for photocatalytic hydrogen evolution, reached at a rate of 94.1 μmol·h–1, which was approximately 2.64 times that of the original g-C3N4. Nitrogen defective g-C3N4 had more electrons and stronger H2O molecule adsorption capacity, identified by systematic experiments and DFT calculations. The carboxyl group of fumaric acid reacted with amino group of urea to prevent self-polymerization process of urea and induce nitrogen defects. The changed band structures promoted the absorption of visible light, effective separation of charge, and increased hydrogen evolution driving force. This work will provide a simple and green approach to prepare nitrogen defective g-C3N4 with tunable band structures.

Cd1–xZnxS Nanorod Solid Solutions with Sulfur Vacancies as Effective Electron Traps for Highly Efficient Photocatalytic Hydrogen Evolution

“…As an intrinsic defect in a semiconductor crystal, vacancies can function as an electron trap to prevent the recombination of photogenerated electron–hole pairs or become a center for electron–hole recombination, which depends on the energy level of the vacancies. Previous reports have showed that the appropriate introduction of vacancies into photocatalytic materials including TiO 2 with O vacancies and g-C 3 N 4 with N or C vacancies could significantly improve the photocatalytic activities. − Crystalline CdS exhibits n-type semiconductor characteristics because of its intrinsic S vacancies, while Cd 1– x Zn x S solid solution has been proven to be a stronger n-type semiconductor as compared to CdS . More recently, several studies have demonstrated that the presence of the surface defects such as S vacancies in the Cd 1– x Zn x S solid solution is beneficial for the photocatalytic H 2 evolution. , Nevertheless, the nature of physical chemistry for the role of the S vacancies in effectively capturing photogenerated electrons to promote the efficient separation of photogenerated electron–hole pairs is still less understood.…”

Structure modulation of g-C3N4in TiO2{001}/g-C3N4hetero-structures for boosting photocatalytic hydrogen evolution

“… 58 The introduced –OH group could increase the surface hydrophilicity of the fabricated TCN heterostructures, which is helpful for enhancing the photocatalytic activity of H 2 evolution. 47 …”

H2+CO2 Synergistic Plasma Positioning Carboxyl Defects in g-C3N4 with Engineered Electronic Structure and Active Sites for Efficient Photocatalytic H2 Evolution

“…Based on the above experimental results, we believe that the plasma modification strategy proposed in this paper can effectively control the defect structure and electronic structure of g-C3N4 material to promote its photocatalytic activity. Although the introduction of appropriate carboxyl groups is beneficial to the g-C3N4 polymer semiconductor, the preparation methods are limited long-term [10,38]. The non-thermal microwave Based on the above experimental results, we believe that the plasma modification strategy proposed in this paper can effectively control the defect structure and electronic structure of g-C 3 N 4 material to promote its photocatalytic activity.…”

“…The non-thermal microwave Based on the above experimental results, we believe that the plasma modification strategy proposed in this paper can effectively control the defect structure and electronic structure of g-C 3 N 4 material to promote its photocatalytic activity. Although the introduction of appropriate carboxyl groups is beneficial to the g-C 3 N 4 polymer semiconductor, the preparation methods are limited long-term [10,38]. The non-thermal microwave plasma method developed here is able to process samples at the kilogram level within minutes in the laboratory stage [39,40], and thus is promising in the rational design and low-cost, scaled-up preparation of structure precisely modulated materials for industrial application.…”