Ge Yiyao, Huang Zhiqi, Ling Chongyi, Chen Bo, Liu Guigao, Zhou Ming, Liu Jiawei, Zhang Xiao, Cheng Hongfei, Liu Guanghua, Du Yonghua, Sun Cheng-Jun, Tan Chaoliang, Huang Jingtao, Yin Pengfei, Fan Zhanxi, Chen Ye, Yang Nailiang, Zhang Hua
Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People's Republic of China.
Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
J Am Chem Soc. 2020 Nov 4;142(44):18971-18980. doi: 10.1021/jacs.0c09461. Epub 2020 Oct 21.
Heterostructured, including heterophase, noble-metal nanomaterials have attracted much interest due to their promising applications in diverse fields. However, great challenges still remain in the rational synthesis of well-defined noble-metal heterophase nanostructures. Herein, we report the preparation of Pd nanoparticles with an unconventional hexagonal close-packed (2H type) phase, referred to as 2H-Pd nanoparticles, via a controlled phase transformation of amorphous Pd nanoparticles. Impressively, by using the 2H-Pd nanoparticles as seeds, Au nanomaterials with different crystal phases epitaxially grow on the specific exposed facets of the 2H-Pd, i.e., face-centered cubic () Au (-Au) on the (002) facets of 2H-Pd while 2H-Au on the other exposed facets, to achieve well-defined -2H- heterophase Pd@Au core-shell nanorods. Moreover, through such unique facet-directed crystal-phase-selective epitaxial growth, a series of unconventional -2H- heterophase core-shell nanostructures, including Pd@Ag, Pd@Pt, Pd@PtNi, and Pd@PtCo, have also been prepared. Impressively, the -2H- heterophase Pd@Au nanorods show excellent performance toward the electrochemical carbon dioxide reduction reaction (CORR) for production of carbon monoxide with Faradaic efficiencies of over 90% in an exceptionally wide applied potential window from -0.9 to -0.4 V (versus the reversible hydrogen electrode), which is among the best reported CORR catalysts in H-type electrochemical cells.
包括异相、贵金属在内的异质结构纳米材料因其在不同领域的广阔应用前景而备受关注。然而，在合理合成结构明确的贵金属异相纳米结构方面仍存在巨大挑战。在此，我们报道了通过非晶态钯纳米颗粒的可控相变制备具有非常规六方密堆积（2H型）相的钯纳米颗粒，即2H-Pd纳米颗粒。令人印象深刻的是，以2H-Pd纳米颗粒为晶种，不同晶相的金纳米材料在2H-Pd的特定暴露面上外延生长，即在2H-Pd的(002)面上生长面心立方（）金（-Au），而在其他暴露面上生长2H-Au，从而实现结构明确的-2H-异相Pd@Au核壳纳米棒。此外，通过这种独特的面定向晶相选择性外延生长，还制备了一系列非常规的-2H-异相核壳纳米结构，包括Pd@Ag、Pd@Pt、Pd@PtNi和Pd@PtCo。令人印象深刻的是，-2H-异相Pd@Au纳米棒在电化学二氧化碳还原反应（CORR）中表现出优异的性能，在-0.9至-0.4 V（相对于可逆氢电极）的极宽应用电位窗口内，一氧化碳的法拉第效率超过90%，这是H型电化学池中报道的最佳CORR催化剂之一。
