氮化碳中氮缺陷和氰基官能化对增强其 CO2 光还原活性的协同作用,Sustainable Energy & Fuels

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氮化碳中氮缺陷和氰基官能化对增强其 CO2 光还原活性的协同作用
Sustainable Energy & Fuels ( IF 5.0 ) Pub Date : 2023-02-11 , DOI: 10.1039/d2se01751b
Shreya Singh ₁ , Pankaj Tiwari ₁ , Guguloth Venkanna ₁ , Kamal K. Pant ₁ , Pratim Biswas _{2,

3}

Affiliation

太阳能驱动的 CO ₂转化以生产有价值的燃料是一种新兴方法，它有可能以可持续和环保的方式使我们摆脱对快速消耗的化石燃料的依赖。氮化碳 (CN) 是一种不含金属的光催化剂，由于其高稳定性和低成本而很有前途，但存在低阳光吸收和光生电子空穴对快速复合的问题。_{在这项研究中，我们提出了一种使用 NaBH 4}还原处理将氰基官能化和 N 空位引入 CN 的简便方法，以克服这些挑战。使用 XRD、FTIR 和 XPS 的结构分析证实了氰基 (–C [三键，长度为 m-dash]

N) CN 框架中吡啶氮的基团和缺陷。CN 中功能化和缺陷的程度，以及因此其光学、电子和光催化性能，受还原过程的温度和流动条件控制。_{得到的最好的材料显示出对 CH 4 的}产物选择性提高了 2.6 倍，生成速率达到 165.7 μmol g _cat^-1 h ^-1。使用 UV-DRS、VB-XPS、EIS 和 DFT 计算分析了最佳的 NaBH ₄还原处理导致带隙降低、电子表面浓度增加、CO _{2还原的热力学驱动力增加以及电荷复合减少。}过度的C [三键，长度为 m-dash]

然而，N 和 N 缺陷被证明会极大地影响电子迁移率、电荷分离和光活性。我们的研究结果为引入 C [三键，长度为 m-dash]

N 基团和 N 缺陷以设计用于光催化应用的高效 CN 提供了最佳条件。

"点击查看英文标题和摘要"

The cooperative role of nitrogen defects and cyano-group functionalization in carbon nitride towards enhancing its CO2 photoreduction activity

Solar-driven CO₂ conversion to produce valuable fuels is an emerging approach that has the potential to shift our reliance away from rapidly depleting fossil fuels in a sustainable and environmentally friendly way. Carbon nitride (CN), a metal-free photocatalyst, is promising due to its high stability and low cost but suffers from low sunlight absorption and fast recombination of photo-generated electron–hole pairs. In this study, we present a facile approach to introduce cyano-functionalization and N vacancies into CN using NaBH₄ reduction treatment to overcome these challenges. Structural analyses using XRD, FTIR and XPS confirmed the incorporation of cyano (–C [triple bond, length as m-dash]

N) groups and deficiencies of pyridinic nitrogen in the CN framework. The extent of functionalization and defects in CN, and consequently its optical, electron and photocatalytic properties are governed by the temperature and flow conditions for the reduction process. The best resulting material showed a 2.6-fold enhancement of product selectivity towards CH₄ with the generation rates reaching 165.7 μmol g_cat⁻¹ h⁻¹. The optimal NaBH₄ reduction treatment results in a lower bandgap, enhanced surface concentration of electrons, higher thermodynamic driving force of CO₂ reduction and reduced charge recombination, analysed using UV-DRS, VB-XPS, EIS and DFT calculations. The excessive C [triple bond, length as m-dash]

N and N-defects, however, are shown to greatly affect the electron mobility, charge separation and photoactivity. Our findings provide optimal conditions to introduce C [triple bond, length as m-dash]

N groups and N-defects to design highly efficient CN for photocatalytic applications.

更新日期：2023-02-11

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