To improve the light harvesting ability and photogenerated carriers separation, N-doped KNb3O8 supported graphitic carbon nitride (g-C3N4) was prepared by a facile calcination method using nitrogen-rich precursor of melamine for the first time. The electric structure of KNb3O8 layers was well regulated by N doping to achieve visible light response. Simultaneously, the formed g-C3N4 was combined with N-doped KNb3O8 to gain heterojunction structure. The separation, transfer and recombination processes of photogenerated charge carriers were investigated by transient photocurrent, electrochemical impedance spectra (EIS) and photoluminescence (PL) measurement. The photocatalytic performances were evaluated by H2 generation and RhB degradation under visible light irradiation. The sample of N-doped KNb3O8/g-C3N4 (KNCN) exhibited the high photocatalytic performance for H2 generation and RhB degradation, which is mainly attributed to the synergistic effects of the extended light harvesting ability and effective charge transportation/separation rate by N-doping and heterojunction formation, respectively. A possible mechanism for the photocatalytic degradation of RhB was proposed. A composite photocatalyst of N-doped KNb3O8 supported g-C3N4 exhibited the significant enhancement on photocatalytic performance for both H2 generation and RhB degradation, which is mainly attributed to the synergistic effects of the extended light harvesting ability and effective charge transportation/separation rate by N-doping and heterojunction formation, respectively.

中文翻译：

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构建 N 掺杂 KNb3O8/g-C3N4 复合材料以在可见光照射下高效光催化 H2 生成和降解

为了提高光捕获能力和光生载流子分离，首次使用三聚氰胺的富氮前驱体通过简便的煅烧方法制备了 N 掺杂的 KNb3O8 负载的石墨碳氮化物 (g-C3N4)。KNb3O8 层的电结构通过 N 掺杂得到很好的调节以实现可见光响应。同时，形成的 g-C3N4 与 N 掺杂的 KNb3O8 结合以获得异质结结构。通过瞬态光电流、电化学阻抗谱（EIS）和光致发光（PL）测量研究了光生载流子的分离、转移和复合过程。通过在可见光照射下产生H2和降解RhB来评估光催化性能。N掺杂的KNb3O8/g-C3N4（KNCN）样品对H2生成和RhB降解表现出很高的光催化性能，这主要归因于N-扩展的光收集能力和有效电荷传输/分离率的协同作用。分别为掺杂和异质结形成。提出了光催化降解 RhB 的可能机制。N掺杂的KNb3O8负载g-C3N4的复合光催化剂对H2生成和RhB降解的光催化性能均表现出显着增强，这主要归因于N扩展的光收集能力和有效电荷传输/分离率的协同效应- 掺杂和异质结形成，分别。这主要归因于分别通过 N 掺杂和异质结形成扩展的光捕获能力和有效电荷传输/分离率的协同效应。提出了光催化降解 RhB 的可能机制。N掺杂的KNb3O8负载g-C3N4的复合光催化剂对H2生成和RhB降解的光催化性能均表现出显着增强，这主要归因于N扩展的光收集能力和有效电荷传输/分离率的协同效应- 掺杂和异质结形成，分别。这主要归因于分别通过 N 掺杂和异质结形成扩展的光捕获能力和有效电荷传输/分离率的协同效应。提出了光催化降解 RhB 的可能机制。N掺杂的KNb3O8负载g-C3N4的复合光催化剂对H2生成和RhB降解的光催化性能均表现出显着增强，这主要归因于N扩展的光收集能力和有效电荷传输/分离率的协同效应- 掺杂和异质结形成，分别。提出了光催化降解 RhB 的可能机制。N掺杂的KNb3O8负载g-C3N4的复合光催化剂对H2生成和RhB降解的光催化性能均表现出显着增强，这主要归因于N扩展的光收集能力和有效电荷传输/分离率的协同效应- 掺杂和异质结形成，分别。提出了光催化降解 RhB 的可能机制。N掺杂的KNb3O8负载g-C3N4的复合光催化剂对H2生成和RhB降解的光催化性能均表现出显着增强，这主要归因于N扩展的光收集能力和有效电荷传输/分离率的协同效应- 掺杂和异质结形成，分别。