催化学报 ›› 2025, Vol. 74: 341-351.DOI: 10.1016/S1872-2067(25)64745-0

• 论文 • 上一篇    下一篇

基于Sm2Ti2O5S2纳米片各向异性电荷迁移性质提升光催化分解水产氢活性

张自豪, 张家铭, 王海峰, 刘梦, 许垚, 刘铠玮, 张博杨, 史珂, 张继方*(), 马贵军*()   

  1. 上海科技大学物质科学与技术学院, 上海 201210
  • 收稿日期:2025-03-07 接受日期:2025-04-27 出版日期:2025-07-18 发布日期:2025-07-20
  • 通讯作者: *电子信箱: magj@shanghaitech.edu.cn (马贵军),zhangjf3@shanghaitech.edu.cn (张继方).
  • 基金资助:
    国家自然科学基金(21972092);上海市自然科学基金(24ZR1451400);上海市新星计划(扬帆专项);上海市新星计划(24YF2729000);上海科技大学启动经费;上海科技大学双一流建设基金

Facet-oriented surface modification for enhancing photocatalytic hydrogen production on Sm2Ti2O5S2 nanosheets

Zihao Zhang, Jiaming Zhang, Haifeng Wang, Meng Liu, Yao Xu, Kaiwei Liu, Boyang Zhang, Ke Shi, Jifang Zhang*(), Guijun Ma*()   

  1. School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
  • Received:2025-03-07 Accepted:2025-04-27 Online:2025-07-18 Published:2025-07-20
  • Contact: *E-mail: magj@shanghaitech.edu.cn (G. Ma), zhangjf3@shanghaitech.edu.cn (J. Zhang).
  • Supported by:
    National Natural Science Foundation of China(21972092);Shanghai Natural Science Foundation of China(24ZR1451400);Shanghai Rising-Star Program(Yangfan Special Project);Shanghai Rising-Star Program(24YF2729000);Starting Foundation of ShanghaiTech University;Double First-Class Initiative Fund of ShanghaiTech University

摘要:

可见光驱动的光催化全水分解技术可实现将太阳能转化为清洁燃料和化学品的目标, 近年来受到广泛关注. 然而, 光催化剂的性能常常受限于宽带隙、低电荷分离效率以及表面催化活性不足等问题. 钙钛矿型氧硫化物Sm2Ti2O5S2 (STOS)作为一种可见光响应光催化剂, 由于其2.1 eV的窄带隙以及适合水氧化还原的能带位置, 显示出良好的应用前景. 然而, STOS的催化性能仍然受到光生电子-空穴分离效率低和表面催化活性不足的制约. 为解决这些问题, 开发具有优异体相电荷分离效率和表面催化性能的光催化剂至关重要. 研究表明, 对于具有各向异性电荷传输特性的半导体材料, 将这一性质与表面助催化剂的选择性修饰相结合可有效提升光催化剂的反应性能.

本文报道了一种熔盐辅助固相反应合成高结晶度STOS纳米片的方法, 通过调控熔盐比例和合成温度, 还可对STOS纳米颗粒尺寸和形貌进行精确调控. 扫描电子显微镜表征结果表明, 光还原反应生成的贵金属单质(Pt, Rh, Au)主要富集在STOS纳米片的{101}晶面上, 而光氧化反应沉积的金属氧化物(PbO2, MnOx)主要位于{001}晶面, 表明STOS纳米片的{001}晶面主要积累空穴而{101}晶面则积累电子, 即STOS半导体具有各向异性电荷迁移特性. 光催化析氢反应表明, 基于STOS的电荷迁移特性, 在{101}晶面精准沉积贵金属产氢助催化剂, 不仅可显著提升析氢速率, 还大幅降低了助催化剂的使用量. 此外, 通过对比不同牺牲剂浓度下氢气析出反应的速控步骤, 揭示了STOS纳米片高效的光生电子-空穴分离特性. 基于STOS的各向异性电荷迁移特性, 可以定向在STOS纳米片{001}晶面上修饰IrO2作为氧化端助催化剂, 在{101}晶面原位光还原沉积Pt@Ir核壳结构纳米颗粒作为还原助催化剂, 在含有空穴牺牲试剂的溶液中, STOS在420 nm光照下的表观量子效率达到35.9%. 采用光辅助开尔文探针力显微镜表征不同晶面间光生电荷密度的差异, 进一步证实了STOS纳米片固有的各向异性电荷迁移特性, 并发现助催化剂的定向担载将不同晶面间表面光电压的差值提升至三倍, 显著增强了内建电场强度. 综上可见, 助催化剂的担载不仅有效提高了电荷分离效率, 并使得氧硫化物对析氢反应具有优异的光催化性能. 进一步利用高活性STOS作为析氢光催化剂, Mo:BiVO4作为析氧光催化剂, 并以[Co(bpy)3]2+/3+作为氧化-还原离子对, 成功构建了可见光驱动的Z-Scheme全水分解体系, 实现了0.175%的太阳能-氢气转换效率.

综上所述, 通过熔盐辅助合成技术和助催化剂晶面定向修饰工艺, 本研究成功提升了STOS光催化剂的电荷分离效率和表面催化活性. 通过进一步优化材料设计和助催化剂配置, STOS有望在太阳能转化和可持续能源开发领域发挥重要作用.

关键词: 氧硫化物, 光催化, 各向异性电荷迁移, 全水分解, 制氢

Abstract:

Oxysulfide semiconductors are promising photocatalysts for visible light-driven water splitting. For a widely studied narrow-bandgap Sm2Ti2O5S2 (STOS), limited bulk charge separation and slow surface reaction heavily restrict its photocatalytic performance. Here, well-crystallized STOS oxysulfide nanosheets, synthesized by a flux-assisted solid-state reaction, were proved to show prominent facet-oriented charge transport property, in which photogenerated electrons migrated to {101} planes and holes to {001} planes of each particle. Hydrogen evolution cocatalysts were therefore precisely positioned on the electron-rich facets to boost the water reduction reaction. In particular, in-situ formation of a Ptshell@Ircore core-shell structure on the electron-rich {101} facets and an IrO2 on the hole-accumulated {001} facets greatly assisted the sacrificial photocatalytic H2 production over STOS, resulting in an apparent quantum yield as high as 35.9% at 420 nm. By using the highly-active STOS as H2 evolution photocatalyst, a Mo:BiVO4 as oxygen evolution photocatalyst, and a [Co(bpy)3]2+/3+ as redox shuttle, a Z-Scheme overall water splitting system was constructed to achieve a solar-to-hydrogen conversion efficiency of 0.175%. This work not only elucidates the facet-dependent charge transfer mechanism on STOS but also proposes an ideal strategy for enhancing its photocatalytic performance.

Key words: Oxysulfide, Photocatalysis, Anisotropic charge transport, Overall water splitting, Hydrogen production