Platinum-based catalysts have been considered the most effective electrocatalysts for the hydrogen evolution reaction in water splitting. However, platinum utilization in these electrocatalysts is extremely low, as the active sites are only located on the surface of the catalyst particles. Downsizing catalyst nanoparticles to single atoms is highly desirable to maximize their efficiency by utilizing nearly all platinum atoms. Here we report on a practical synthesis method to produce isolated single platinum atoms and clusters using the atomic layer deposition technique. The single platinum atom catalysts are investigated for the hydrogen evolution reaction, where they exhibit significantly enhanced catalytic activity (up to 37 times) and high stability in comparison with the state-of-the-art commercial platinum/carbon catalysts. The X-ray absorption fine structure and density functional theory analyses indicate that the partially unoccupied density of states of the platinum atoms' 5d orbitals on the nitrogen-doped graphene are responsible for the excellent performance.

Platinum nanoparticles

Carbon fibers

10.1038/ncomms13638

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Citations (1,784)

A high-energy sulfur cathode in carbonate electrolyte by eliminating polysulfides via solid-phase lithium-sulfur transformation

Nature Communications (2018)

Xia Li Mohammad Norouzi Banis Andrew Lushington Xiaofei Yang Qian Sun

Abstract Carbonate-based electrolytes demonstrate safe and stable electrochemical performance in lithium-sulfur batteries. However, only a few types of sulfur cathodes with low loadings can be employed and the underlying electrochemical mechanism of lithium-sulfur batteries with carbonate-based electrolytes is not well understood. Here, we employ in operando X-ray absorption near edge spectroscopy to shed light on a solid-phase lithium-sulfur reaction mechanism in carbonate electrolyte systems in which sulfur directly transfers to Li 2 S without the formation of linear polysulfides. Based on this, we demonstrate the cyclability of conventional cyclo-S 8 based sulfur cathodes in carbonate-based electrolyte across a wide temperature range, from −20 °C to 55 °C. Remarkably, the developed sulfur cathode architecture has high sulfur content (>65 wt%) with an areal loading of 4.0 mg cm −2 . This research demonstrates promising performance of lithium-sulfur pouch cells in a carbonate-based electrolyte, indicating potential application in the future.

Lithium carbonate

10.1038/s41467-018-06877-9

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Citations (215)

Atomic layer deposited Pt-Ru dual-metal dimers and identifying their active sites for hydrogen evolution reaction

Nature Communications (2019)

Lei Zhang Rutong Si Hanshuo Liu Ning Chen Qi Wang

Single atom catalysts exhibit particularly high catalytic activities in contrast to regular nanomaterial-based catalysts. Until recently, research has been mostly focused on single atom catalysts, and it remains a great challenge to synthesize bimetallic dimer structures. Herein, we successfully prepare high-quality one-to-one A-B bimetallic dimer structures (Pt-Ru dimers) through an atomic layer deposition (ALD) process. The Pt-Ru dimers show much higher hydrogen evolution activity (more than 50 times) and excellent stability compared to commercial Pt/C catalysts. X-ray absorption spectroscopy indicates that the Pt-Ru dimers structure model contains one Pt-Ru bonding configuration. First principle calculations reveal that the Pt-Ru dimer generates a synergy effect by modulating the electronic structure, which results in the enhanced hydrogen evolution activity. This work paves the way for the rational design of bimetallic dimers with good activity and stability, which have a great potential to be applied in various catalytic reactions.

Bimetallic strip

Nanomaterials

10.1038/s41467-019-12887-y

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Citations (469)

Unravelling the Chemistry and Microstructure Evolution of a Cathodic Interface in Sulfide-Based All-Solid-State Li-Ion Batteries

ACS Energy Letters (2019)

Xia Li Zhouhong Ren Mohammad Norouzi Banis Sixu Deng Yang Zhao

All-solid-state lithium-ion batteries (SSLIBs) are promising candidates to meet the requirement of electric vehicles due to the intrinsic safety characteristics and high theoretical energy density. A stable cathodic interface is critical for maximizing the performance of SSLIBs. In this study, operando X-ray absorption near-edge spectroscopy (XANES) combined with transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) is employed to investigate the interfacial behavior between the Ni-rich layered cathodes and sulfide solid-state electrolyte. The study demonstrates a metastable intermediate state of sulfide electrolyte at high voltage and parasitic reactions with cathodes during the charge/discharge process, which leads to the surface structural reconstruction of Ni-rich cathodes. Constructing a uniform interlayer by atomic layer deposition (ALD) is also employed in this study to further investigate the cathodic interface stability. These results provide new insight into the cathodic interface reaction mechanism and highlight the importance of advanced operando characterizations for SSLIBs.

XANES

10.1021/acsenergylett.9b01676

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Citations (204)

Manipulation of an ionic and electronic conductive interface for highly-stable high-voltage cathodes

Nano Energy (2019)

Sixu Deng Biqiong Wang Yifei Yuan Xia Li Qian Sun

10.1016/j.nanoen.2019.103988

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Citations (51)

Trimetallic Pt–Pd–Ni octahedral nanocages with subnanometer thick-wall towards high oxygen reduction reaction

Nano Energy (2019)