催化学报

催化学报 ›› 2020, Vol. 41 ›› Issue (1): 114-121.DOI: 10.1016/S1872-2067(19)63459-5

• 光催化产氢 • 上一篇    下一篇

化学镀法制备CoP量子点修饰g-C3N4用于光催化产氢

戚克振a,b, 吕文秀a, Iltaf Khanc, 刘书源d,e   

  1. a 沈阳师范大学化学化工学院能源与环境催化研究所, 辽宁沈阳 110034;
    b 福州大学化学学院能源与环境光催化国家重点实验室, 光催化研究所, 福建福州 350116;
    c 黑龙江大学化学化工与材料学院功能无机材料化学教育部重点实验室, 黑龙江哈尔滨 150080;
    d 沈阳医学院基础医学院药理学教研室, 辽宁沈阳 110034;
    e 哈尔滨师范大学物理与电子工程学院光电带隙材料省部共建教育部重点实验室, 黑龙江哈尔滨 150025
  • 收稿日期:2019-07-05 修回日期:2019-07-23 出版日期:2020-01-18 发布日期:2019-10-22
  • 通讯作者: 刘书源
  • 基金资助:
    国家自然科学基金（51602207）；辽宁省高等学校创新人才支持计划（LR2017074）；福州大学能源与环境光催化国家重点实验室开放课题（SKLPEE-KF201810）；辽宁省教育厅科学研究项目（LQN201712）；辽宁省博士科研启动基金（20170520011），沈阳市创新人才计划项目（RC180211）.

Photocatalytic H2 generation via CoP quantum-dot-modified g-C3N4 synthesized by electroless plating

Kezhen Qia,b, Wenxiu Lva, Iltaf Khanc, Shu-yuan Liud,e   

  1. a Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, Liaoning, China;
    b Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350116, Fujian, China;
    c Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Harbin 158308, Heilongjiang, China;
    d Department of Pharmacology, Shenyang Medical College, Shenyang 110034, Liaoning, China;
    e Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, College of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang, China
  • Received:2019-07-05 Revised:2019-07-23 Online:2020-01-18 Published:2019-10-22
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (51602207), the Doctoral Scientific Research Foundation of Liaoning Province (20170520011), the Program for Liaoning Excellent Talents in Universities (LR2017074), the Open Project Program of the State Key Laboratory of Photocatalysis on Energy and Environment (SKLPEE-201810), Fuzhou University, the Scientific Research Project of the Educational Department of Liaoning Province (LQN201712), and Shenyang Excellent Talents in Universities (RC180211).

PDF

629

摘要： 光催化分解水制氢被认为是解决当前能源危机和环境污染问题的重要途径之一.在众多光催化剂中，石墨相氮化碳（g-C3N4）因其具有高的热稳定性、高的化学稳定性、合适的能带位置以及成本低廉等优点，受到光催化领域研究者的广泛关注，成为研究热点.然而，由于g-C3N4的禁带宽度较大（Eg=2.7eV），导致其对可见光的响应较差，而且光生电子-空穴对在其中易于复合，从而导致其光催化产氢活性较低.已有研究表明，助催化剂可以有效地促进催化剂中光生载流子的分离和传输，从而提高光催化剂的光催化活性和氢气的产生速率.目前使用最广泛的助催化剂多为贵金属（Au，Ag，Pt和Pd等），然而贵金属储量低、成本高，极大地限制了其实际应用.因而，开发适用于光催化水分解制氢的非贵金属助催化剂成为该领域的研究热点.其中，用非贵金属助催化剂修饰g-C3N4制备高效光催化剂分解水制氢技术引起了人们极大的兴趣.
过渡金属磷化物（FeP，CoP，CuP，NiP等）是一种有效的光催化辅助催化剂.然而，这些金属磷化物的合成通常使用有毒的有机磷化合物和白磷或涉高温煅烧.特别是在传统水热法制备金属磷化物过程中会释放大量氢气，导致容器内压力过高，造成较大的安全问题.据报道，在这些磷化物中，磷化钴由于其合适的能带结构和较高的导电性，作为光催化分解水助催化剂受到了广泛关注.然而，截至目前，关于磷化钴作为助催化剂用于光催化的实用技术报道很少，特别是在温和条件下制备磷化钴修饰的g-C3N4复合光催化剂的研究还有待进行.
本文研究了以CoP作为助催化剂来改进g-C3N4（制备g-C3N4/CoP），并用于光催化水裂解制氢气.复合光催化剂g-C3N4/CoP经由两步反应合成.第一步采用尿素热分解法制备g-C3N4，第二步通过化学镀法将CoP修饰在g-C3N4表面.采用XRD，TEM，UV-DRS和XPS等手段表征了g-C3N4/CoP光催剂的性质.结果表明，CoP以量子点（QDs）形式均匀分布在g-C3N4表面，显著提高了g-C3N4的光催化活性.不同CoP负载量的样品中，g-C3N4/CoP-4%表现出优异的光催化活性，H2生成速率为936μmol g-1h-1，甚至高于4% Pt负载的g-C3N4（H2的生成速率仅为665μmol g-1 h-1）.从紫外可见光谱上看，g-C3N4在451nm达到吸收波长上限，但与CoP复合后，g-C3N4/CoP-4%的吸收波长上限延展到497nm.此外，光致发光和光电流测试结果证实，将CoP量子点负载到g-C3N4上不仅可以降低光生电荷-空穴对的复合，而且可以改善光生e--h+对的转移，从而提高光催化剂的产氢性能.这项工作为开发高效的非贵金属助催化剂修饰g-C3N4的技术提供了一个可行策略，所制材料在光催化制氢领域显示出潜在的应用前景.

关键词: 光催化, CoP, 量子点, 化学镀, 产氢, g-C3N4

Abstract: Photocatalytic water splitting is a promising method for hydrogen production. Numerous efficient photocatalysts have been synthesized and utilized. However, photocatalysts without a noble metal as the co-catalyst have been rarely reported. Herein, a CoP co-catalyst-modified graphitic-C3N4 (g-C3N4/CoP) is investigated for photocatalytic water splitting to produce H2. The g-C3N4/CoP composite is synthesized in two steps. The first step is related to thermal decomposition, and the second step involves an electroless plating technique. The photocatalytic activity for hydrogen evolution reactions of g-C3N4 is distinctly increased by loading the appropriate amount of CoP quantum dots (QDs). Among the as-synthesized samples, the optimized one (g-C3N4/CoP-4%) shows exceptional photocatalytic activity as compared with pristine g-C3N4, generating H2 at a rate of 936 μ mol g-1 h-1, even higher than that of g-C3N4 with 4 wt% Pt (665 μmol g-1 h-1). The UV-visible and optical absorption behavior confirms that g-C3N4 has an absorption edge at 451 nm, but after being composited with CoP, g-C3N4/CoP-4% has an absorption edge at 497 nm. Furthermore, photoluminescence and photocurrent measurements confirm that loading CoP QDs to pristine g-C3N4 not only enhances the charge separation, but also improves the transfer of photogenerated e--h+ pairs, thus improving the photocatalytic performance of the catalyst to generate H2. This work demonstrates a feasible strategy for the synthesis of highly efficient metal phosphide-loaded g-C3N4 for hydrogen generation.

Key words: Photocatalysis, CoP quantum dots, Electroless plating, H2 generation, g-C3N4