第一作者：Yuanyuan Zhou

通讯作者：Zidong Wei

通讯单位：Chongqing University

研究内容：

一个高效的HOR催化剂必须在一个相对较高的电位范围内保持无氧的金属表面。这一要求自动排除了钌，因为它在氢吸附/解吸电位区域容易被氧化。本文报告了部分限域在超薄TiO₂晶体(Ru@TiO₂)晶格中的Ru簇，它可以有效地催化HOR达到0.9V_RHE的电位，并且在酸性和碱性条件下其质量活性都高于PtRu催化剂。此外，这种Ru@TiO₂催化剂的HOR活性不受1000ppm CO 杂质的影响。即使在10vol% 的高CO含量下，Ru@TiO₂仍能选择性地催化HOR。受限的Ru簇沿着TiO₂的晶格生长，并形成大量的Ru-Ti键。这种原子连接的共晶提供了有效的电子转移从富电子TiO₂到Ru金属，导致在HOR过程中CO吸附动力学缓慢。

要点一：

这篇文章报道了一个不同寻常的发现，Ru簇被部分限域在超薄的TiO₂晶体的晶格中后，可以在高达0.9V（vsRHE）的电位下表现出特别高的HOR活性和高达10vol% CO 的杰出的耐受性。

要点二：

对Ru簇限域到TiO2中具有优异的HOR活性和高的抗氧化能力以及显著的对CO的耐受性的机理做出了严谨细致的分析。Ru簇和TiO₂的原子链接使富含电子的TiO₂（负半导体）到金属Ru的有效电子转移，结果，晶格限域的Ru簇的价带充满了TiO₂脱氧产生的多余电子，导致CO吸附受阻并具有和块状金属钌类似的抗氧化能力。

要点三：

这一发现表明，纳米粒子的表面亲氧性和电子结构可以通过半导体中的晶格限制进行有效修饰，并为设计具有独特性质的催化剂提供了一种替代概念，可用于催化领域及其他领域。

Fig.1 | X-ray diffraction. XRD patterns of  TiO₂ and Ru@TiO₂ before and after annealing.

Fig.2 | Electron microscopy of  TiO₂ and Ru@TiO₂.a, Lattice evolution during production of lattice-confined Ru@TiO₂:lattice open, lattice closed, lattice confined.b–e, TEM (b,c) and HRTEM (d,e) images of TiO₂ before annealing, showing the urchin-like TiO₂ spheres assembled with amorphous TiO₂ nanobelts.The red dashed lines mark open-lattice defects (e). f–i, TEM (f,g)and HRTEM (h,i) images of  Ru@TiO₂ after annealing; the morphology of theurchin-like sphere was maintained and Ru NPs were evenly distributed along the TiO₂ nanobelts. j, STEM images with EDX spectroscopy of urchin-likeRu@ TiO₂ nanospheres. k, HAADF images with EDX spectroscopy of Ru@TiO₂nanobelts. The element distribution of Ru (blue), Ti (red) and O(green) confirmed the uniform composition.

Fig.3 | HRTEM and HAADF-STEM of Ru@TiO₂.a, HRTEM images of Ru@TiO₂.b, Enlarged view of the interface between Ru and TiO₂.c–f, Selected-areaFFTpatterns of Ru (c) and TiO₂(e), and inverse FFT patterns of Ru (d) and TiO₂(f). Red and green circles show the selected area electrondiffraction(SAED) pattern of Ru and TiO₂,respectively. The grey dashed lines (b,d,f) show the newly formedareas of crystal stucture at the interface between Ru andTiO₂.g–k, HAADF-STEM images of Ru clusters confined in the TiO₂nanobelt cystal. h and i show the Ru confined in TiO₂(004), and j and k show theRuconfined in TiO₂(101). The coloured circles represent the Ti–Ru connections at theinterface with similar angles, where blue, red and grey represent Ru,Ti and O, respectively.

Fig.4 | The catalytic performance for HOR. a,b, Polarization curves ofRu@TiO₂,PtRu/Ccom and Ru/C catalysts (all of the three catalysts with apreciousmetalloading of 25_{μgpreciousmetal}cm⁻²)in H₂-saturated0.1 M KOH (a) and 0.1 M HClO₄(b) solutions at a scan rate of 10 mV s⁻¹and rotation speed of 1,600 r.p.m. c, Precious metal mass activities (MA) at 20 mV were recordedat room temperature in H₂-saturated0.1 M KOH solution and 0.1 M HClO₄solutionfor Ru@TiO₂,PtRu/C_com and Ru/C catalysts. Error bars correspond to the standard deviation of three independent measurements.

Fig.5 | The catalytic performance for HOR in the presence of CO. a,b, Polarization curves of Ru@TiO₂ and PtRu/Ccom in H₂/1,000ppm CO-saturated 0.1M KOH (a) and 0.1 M HClO₄(b) solutions at a scan rate of 10 mV s⁻¹ and a rotation speed of 1,600 r.p.m. c,d, Polarization curves ofRu@TiO₂,PtRu/CcomandRu/C in 0.1 M KOH (c) and 0.1 M HClO₄ solutions (d) (H₂:CO= 10:1 vol/vol) at a scan rate of 10 mV s⁻¹and a rotation speed of 1,600 r.p.m. e, Relativecurrent–time chronoamperometry response of Ru@TiO₂,PtRu/Ccom and Pt/Ccom in H₂/1,000ppm CO-saturated 0.1 M KOH solution at 0.1 V versus RHE

Fig.6 | XPS and EXAFS spectra of the produced catalysts. a–c, XPSspectra of the Ru 3d (a), Ti 2p (b) and O 1s (c) binding energy ofRu@TiO₂,Ru/C andTiO₂.d, Ru K-edge X-ray absorption near-edge structure spectra of Ru@TiO₂and Ru/C obtained using Ru powder and commercial RuO₂as references.e,Fourier-transformed (FT) k3-weighted χ(k)-function of the EXAFSspectra for the Ru K-edge. f, Relation between the Ru K-edgeabsorption energy (E0) and valence states for Ru@TiO₂,Ru/C and reference materials. g, Wavelet transforms for thek3-weighted EXAFS signals.

Fig.7 | Steady stability testing of the catalysts for the HOR. a,b,Relative current–time chronoamperometry response of Ru@TiO₂ and Ru/C in anH₂-saturated 0.1 M KOH solution at 0.1 V versus RHE operated on an RDE (a) and aGDE (b). The loading for a is 25 μgRu cm⁻².

参考文献

Yuanyuan Zhou, Zhenyang Xie, Jinxia Jiang, Jian Wang, Xiaoyun Song, Qian He,Wei Ding and Zidong Wei.Lattice-confined Ru clusters with high CO toleranceand activity for the hydrogen oxidation reaction. NatCatal 3, 454–462 (2020). https://doi.org/10.1038/s41929-020-0446-9