催化学报

催化学报 ›› 2019, Vol. 40 ›› Issue (2): 160-167.DOI: 10.1016/S1872-2067(19)63283-3

• 论文 • 上一篇    下一篇

非贵金属助催化剂Ni3N修饰g-C3N4用于可见光催化产氢的研究

葛建华a,b, 刘玉洁a, 江道传b, 张磊b, 杜平武b   

  1. a 安徽理工大学地球与环境学院, 安徽淮南 232001;
    b 中国科学技术大学化学与材料科学学院材料科学与工程系, 中国科学院能量转换材料重点实验室, 能源材料化学协同创新中心, 安徽合肥 230026
  • 收稿日期:2018-10-09 修回日期:2018-12-14 出版日期:2019-02-28 发布日期:2019-01-11
  • 通讯作者: 葛建华, 杜平武
  • 基金资助:

    国家重点研发计划（2017YFA0402800）；国家自然科学基金（51772285，21473171，51878004）；安徽自然科学基金（1808085ME139）；中央高校基本业务费.

Integrating non-precious-metal cocatalyst Ni3N with g-C3N4 for enhanced photocatalytic H2 production in water under visible-light irradiation

Jianhua Gea,b, Yujie Liua, Daochuan Jiangb, Lei Zhangb, Pingwu Dub   

  1. a School of Earth and Environment, Anhui University of Science & Technology, Huainan 232001, Anhui, China;
    b CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, Collaborative Innovation Center of Chemistry for Energy Materials(iChEM), University of Science and Technology of China(USTC), Hefei 230026, Anhui, China
  • Received:2018-10-09 Revised:2018-12-14 Online:2019-02-28 Published:2019-01-11
  • Contact: S1872-2067(19)63283-3
  • Supported by:

    This work was financially supported by the National Key Research and Development Program of China (2017YFA0402800), the National Natural Science Foundation of China (51772285, 21473170, 51878004), the Natural Science Fund of of Anhui Province(1808085ME139), and the Fundamental Research Funds for the Central Universities.

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摘要：

近年来，利用太阳光光解水制氢被认为是解决当前能源短缺和环境污染问题的重要途径之一.众所周知，助催化剂可以有效的降低光催化产氢反应的活化能，提供产氢反应的活性位点，有效的促进催化剂中光生载流子的传输与分离，从而提高光催化剂产氢体系的反应活性和稳定性.然而，鉴于贵金属助催化剂（Pt，Au和Pd等）储量低、成本高，极大地制约了其应用.因而，开发出适用于光催化水分解制氢的非贵金属助催化剂尤为重要.
石墨相氮化碳（g-C3N4）因其具有热稳定性、化学稳定性高以及制备成本低廉等优点，成为光催化领域研究的热点.然而，由于g-C3N4的禁带宽度（Eg=2.7eV）较宽，致使其对可见光的响应能力较弱，并且在光催化反应过程中其光生电子-空穴对易复合，从而导致其光催化产氢活性较低.因此，如何开发出含非贵金属助催化剂的g-C3N4高效、稳定的太阳光催化分解水制氢体系引起了人们极大的关注.
本文通过水热法-高温氨化法首次将非贵金属Ni3N作为助催化剂来修饰g-C3N4，增强其可见光光催化性能（λ >420nm）.采用XRD、SEM、EDS、Mapping、UV-Vis、XPS和TEM等手段对Ni3N/g-C3N4光催化体系进行了表征.结果表明，Ni3N纳米颗粒成功的负载到g-C3N4表面且没有改变g-C3N4的层状结构.此外，采用荧光光谱分析（PL）、阻抗测试（EIS）和光电流谱进行表征，结果显示，Ni3N纳米颗粒可有效促进催化剂中光生载流子的传输与分离，抑制电子-空穴对的复合.同时，将功率为300W且装有紫外滤光片（λ > 420nm）的氙灯作为可见光光源进行光催化产氢实验结果表明，引入了一定量的Ni3N可以极大提高g-C3N4的光催化活性，其中，Ni3N/g-C3N4#3的产氢量为~305.4μmol·h-1·g-1，大约是单体g-C3N4的3倍.此外，在450nm单色光照射下，Ni3N/g-C3N4光催化产氢体系的量子效率能达到~0.45%，表明Ni3N/g-C3N4具有将入射电子转化为氢气的能力.循环产氢实验表明，Ni3N/g-C3N4在光催化产氢过程中有着较好的产氢活性和稳定性.最后，阐述了Ni3N/g-C3N4体系的光催化产氢反应机理.本文采用的原料价格低廉，性能优异，制备简单，所制材料在光催化制氢领域展现出重要前景.

关键词: 光催化, Ni3N, 助催化剂, 产氢, g-C3N4

Abstract:

Photocatalytic H2 production via water splitting in a noble-metal-free photocatalytic system has attracted much attention in recent years. In this study, noble-metal-free Ni3N was used as an active cocatalyst to enhance the activity of g-C3N4 for photocatalytic H2 production under visible-light irradiation (λ > 420 nm). The characterization results indicated that Ni3N nanoparticles were successfully loaded onto the g-C3N4, which accelerated the separation and transfer of photogenerated electrons and resulted in enhanced photocatalytic H2 evolution under visible-light irradiation. The hydrogen evolution rate reached~305.4 μmol h-1 g-1, which is about three times higher than that of pristine g-C3N4, and the apparent quantum yield (AQY) was~0.45% at λ=420. Furthermore, the Ni3N/g-C3N4 photocatalyst showed no obvious decrease in the hydrogen production rate, even after five cycles under visible-light irradiation. Finally, a possible photocatalytic hydrogen evolution mechanism for the Ni3N/g-C3N4 system is proposed.

Key words: Photocatalysis, Ni3N, Cocatalyst, Hydrogen evolution, g-C3N4