第一作者：Yuanyuan Zhou
通訊作者：Zidong Wei
通訊單位：Chongqing University
研究內(nèi)容：
一個高效的HOR催化劑必須在一個相對較高的電位范圍內(nèi)保持無氧的金屬表面。這一要求自動排除了釕，因為它在氫吸附/解吸電位區(qū)域容易被氧化。本文報告了部分限域在超薄TiO2晶體(Ru@TiO2)晶格中的Ru簇，它可以有效地催化HOR達(dá)到0.9VRHE的電位，并且在酸性和堿性條件下其質(zhì)量活性都高于PtRu催化劑。此外，這種Ru@TiO2催化劑的HOR活性不受1000ppm CO 雜質(zhì)的影響。即使在10vol% 的高CO含量下，Ru@TiO2仍能選擇性地催化HOR。受限的Ru簇沿著TiO2的晶格生長，并形成大量的Ru-Ti鍵。這種原子連接的共晶提供了有效的電子轉(zhuǎn)移從富電子TiO2到Ru金屬，導(dǎo)致在HOR過程中CO吸附動力學(xué)緩慢。
要點(diǎn)一：
這篇文章報道了一個不同尋常的發(fā)現(xiàn)，Ru簇被部分限域在超薄的TiO2晶體的晶格中后，可以在高達(dá)0.9V（vsRHE）的電位下表現(xiàn)出特別高的HOR活性和高達(dá)10vol% CO 的杰出的耐受性。
要點(diǎn)二：
對Ru簇限域到TiO2中具有優(yōu)異的HOR活性和高的抗氧化能力以及顯著的對CO的耐受性的機(jī)理做出了嚴(yán)謹(jǐn)細(xì)致的分析。Ru簇和TiO2的原子鏈接使富含電子的TiO2（負(fù)半導(dǎo)體）到金屬Ru的有效電子轉(zhuǎn)移，結(jié)果，晶格限域的Ru簇的價帶充滿了TiO2脫氧產(chǎn)生的多余電子，導(dǎo)致CO吸附受阻并具有和塊狀金屬釕類似的抗氧化能力。
要點(diǎn)三：
這一發(fā)現(xiàn)表明，納米粒子的表面親氧性和電子結(jié)構(gòu)可以通過半導(dǎo)體中的晶格限制進(jìn)行有效修飾，并為設(shè)計具有獨(dú)特性質(zhì)的催化劑提供了一種替代概念，可用于催化領(lǐng)域及其他領(lǐng)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 25μgpreciousmetalcm?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/Ccom 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.
參考文獻(xiàn)
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
