第一作者：澳大利亚国立大学 Zhehao Sun Shuwen Cheng
通讯作者：澳大利亚国立大学 殷宗友
DOI：https://doi.org/10.1002/adma.202406088
随着淡水资源的日益匮乏，光催化海水分解制氢得到了广泛的关注。在本研究中，引入了一种新型光催化剂，该催化剂由镀有N掺杂C的Cu核心组成，并以单Co原子装饰（Co-NC@Cu），用于从海水中太阳能制氢。该催化剂在不使用贵金属或牺牲剂的情况下，具有9080µmolg−1h−1的产氢效率，即4.78%的太阳能制氢效率，并且具有优异的长期稳定性，连续运行超过340 h。优异的性能归因于几个关键因素。首先，聚焦光诱导的光热效应增强了氧化还原反应能力，而盐离子使催化剂表面周围的电荷极化延长了载流子寿命。此外，Co─NC@Cu表现出优异的广光吸收，促进光激发电荷的产生。理论计算表明，Co─NC为活性位，在还原反应中表现出较低的能垒。此外，Cu纳米颗粒的局部表面等离子体共振（LSPR）形成的强表面电场进一步降低了氧化还原反应的能量壁垒，提高了海水分解活性。这项工作为将反应环境、广泛的太阳能吸收、LSPR和活性单原子整合到核壳光催化剂设计中，以实现高效和强大的太阳能驱动的海水分裂提供了有价值的见解。
Figure 1. Synthesis, composition and morphology of Co─NC@Cu. a) Schematic diagram of the synthesis process of Co─NC@Cu. b) XRD patterns of CuO, NC@Cu, Co─NC@Cu and the corresponding standard PDF cards. c) TEM images of Co─NC@Cu and d) zoomed-in image of a Cu NP edge. e) The HADDF-STEM and EDS element mapping of Co─NC@Cu for f) Cu, g) Co, h) N, and i) C. The AC HADDF-STEM local images of j) Co single atoms anchored N-doped carbon shell (i.e., Co─NC), and k) the core Cu.
Figure 2. a) The XANES and b) FT-EXAFS of Co K-edge for Co foil, CoPc and Co─NC@Cu. WT-EXAFS for c) Co foil, d) CoPc and e) Co─NC@Cu. f) XPS spectra for Co 2p. g) Raman spectra for Co─NC@Cu before and after 343 h reaction.
Figure 3. a) CL intensity maps integrated across different wavelength ranges from 400 to 900 nm. b) CL emission signal for Co─NC@Cu with the corresponding scanning electron microscopy (SEM) image. c) CL emission full/Sum spectrum (blue) and the spectra at the different sites indicated in b) with the corresponding colors. d) EELS spectra obtained from sites I, II, and III as indicated in the inset image. e) EELS mapping of Co─NC@Cu NPs at 2.0 ± 0.1, 2.3 ± 0.1, and 2.6 ± 0.1 eV, corresponding to the blue-shaded peak region in the EELS spectra in d).
Figure 4. a) Comparison of the H2 production rate from light-driven seawater splitting between Co─NC@Cu and its control samples. b) The H2 production rate and reaction temperature as dependent on the NaCl concentration. c) STH efficiency recorded every 2 h in the first 44 h reaction. d) Long-term stability tests up to 343 h.
Figure 5. a) The simulated E-field distribution of Co─NC@Cu under light irradiation at different wavelength ranges using FDTD simulations. b) The maximum E-field (EF) intensity versus. incident light wavelengths for Cu NPs with different size. c) The maximum E-field intensity versus. incident light wavelengths for Co─NC@Cu with c) 5 nm and d) 10 nm shell thickness. The E-field intensity of the incident light was set to 1 V/m, and the incident light intensity was set to 600 mW cm−2. Calculated Gibbs free energy of e) HER and f) OER on Co─NC@Cu, with E-field perturbation included if mentioned. Four transition state (TS) processes include TS1 as *H2O → *OH + *H, TS2 as *OH → *O + *H, TS3 as *O + *H2O → *OOH + *H, and TS4 as *OOH → *O2 + *H.
Atomic Dispersed Co on NC@Cu Core-Shells for Solar Seawater Splitting
https://doi.org/10.1002/adma.202406088
