物理化学学报 >> 2023, Vol. 39 >> Issue (6): 2212009.doi: 10.3866/PKU.WHXB202212009

所属专题： S型光催化剂

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S-型MnCo2S4/g-C3N4异质结光催化产氢性能研究

孙涛(), 李晨曦, 鲍钰鹏, 樊君, 刘恩周()   

  • 收稿日期:2022-12-04 录用日期:2023-01-03 发布日期:2023-01-06
  • 通讯作者: 孙涛,刘恩周 E-mail:chemstst@nwu.edu.cn;liuenzhou@nwu.edu.cn
  • 作者简介:第一联系人：

    † These authors contributed equally to this paper.

S-Scheme MnCo2S4/g-C3N4 Heterojunction Photocatalyst for H2 Production

Tao Sun(), Chenxi Li, Yupeng Bao, Jun Fan, Enzhou Liu()   

  • Received:2022-12-04 Accepted:2023-01-03 Published:2023-01-06
  • Contact: Tao Sun, Enzhou Liu E-mail:chemstst@nwu.edu.cn;liuenzhou@nwu.edu.cn

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摘要：

本文通过简单的水热法和热解法分别得到MnCo2S4和g-C3N4催化剂，之后采用溶剂蒸发法将MnCo2S4和g-C3N4纳米片结合构建获得无贵金属的S-型MnCo2S4/g-C3N4异质结。研究结果表明，优化后的复合材料具有良好的光催化产氢活性，其产氢速率最高可到2979 μmol∙g−1·h−1，分别为g-C3N4 (113 μmol∙g−1·h−1)和MnCo2S4 (341 μmol∙g−1·h−1)的26.4和8.7倍。这主要归因于形成的S-型异质结具有比单体更低的反应阻抗，更高的光电流和高效的电子-空穴分离能力，以及低的析氢过电势。本研究为开发稳定、高效的非贵金属产氢异质结催化剂提供了实验基础。

关键词: MnCo2S4, g-C3N4, S-型异质结, 光催化分解水

Abstract:

The increased global demand for energy and the enhanced deterioration of the environment are the two urgent challenges of the 21st century on the way to sustainable development for human society. Currently, green and renewable energy conversion technology has received much attention as a substitute for limited and non-renewable fossil fuels. Hydrogen energy is advantageous because of its high energy capacity (142 MJ·kg−1) and its production by green conversion technology, consisting of H2 reacting with O2 to generate H2O. It can establish a clean and sustainable hydrogen economic system, as well as reduce the utilization of fossil fuels and carbon dioxide emissions. Water splitting technology is an efficient approach to acquire the featured H2 energy of the green reaction (2H2O → 2H2 + O2) through electrocatalytic and photocatalytic reactions. Photocatalysis technology, with the advantage of huge solar energy utilization, has been widely regarded as a promising method for the realization of this chemical synthesis. Among photocatalysis technologies, photocatalytic H2 production from water is considered a promising approach to obtain H2 energy due to its environmentally friendly energy conversion. However, the effectiveness of acquiring H2 energy through photocatalytic water splitting is intimately related with photocatalysts. In general, photocatalysts still face the big challenge of their low solar energy utilization efficiency, which restricts the large-scale application of photocatalytic technology to obtain H2 energy. Thus, developing highly efficient photocatalysts for H2 production is critical in promoting this technology moving forward, and obtaining renewable energy. Herein, we successfully construct the S-scheme MnCo2S4/g-C3N4 heterojunction through an expedient physical mixing process at a low temperature, which can be separately obtained via the pyrolysis process and hydrothermal method. The H2 production rate of MnCo2S4/g-C3N4 heterojunction can achieve up to 2979 µmol·g−1·h−1, which is 26.4 and 8.7 times higher than those of g-C3N4 (113 µmol·g−1·h−1) and MnCo2S4 (341 µmol·g−1·h−1), respectively, and presents a superior stability in three continuous cycles during H2 production tests. The high H2 production of MnCo2S4/g-C3N4 heterojunction is mainly ascribed to the following three reasons: i) The light absorption region of the heterojunction is extended to visible light. ii) MnCo2S4/g-C3N4 possesses low impedance during the reaction, high photocurrent density, and more exposed sites in solution. iii) The efficient reservation of active electron-hole pairs greatly enhances the ratio of electrons reacting with H* species to generate H2 over MnCo2S4/g-C3N4 heterojunction. This work provides an efficient approach to constructing advanced g-C3N4-based photocatalysts through hybridization with metal sulfides to form S-scheme heterojunctions.

Key words: MnCo2S4, Carbon nitride, S-scheme heterojunction, Photocatalytic H2 production from water splitting