Publications by authors named "Huajie Ze"

3 Publications

  • Page 1 of 1

Molecular Insight of the Critical Role of Ni in Pt-Based Nanocatalysts for Improving the Oxygen Reduction Reaction Probed Using an SERS Borrowing Strategy.

J Am Chem Soc 2021 Jan 15;143(3):1318-1322. Epub 2021 Jan 15.

College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, College of Materials, iChEM, Xiamen University, Xiamen 361005, China.

PtNi alloy catalysts have excellent catalytic activity and are considered some of the most promising electrocatalysts capable of replacing pure Pt for the oxygen reduction reaction (ORR). For PtNi alloys, Ni-doping can improve performance by changing the electronic and structural properties of the catalyst surface and its interaction with reaction intermediates. However, to date there is no direct spectral evidence detecting or identifying the effect of Ni on the ORR in PtNi alloy catalysts. Herein, we introduce a surface-enhanced Raman spectroscopic (SERS) "borrowing" strategy for investigating ORR processes catalyzed by [email protected] nanoparticles (NPs). The bond vibration of adsorbed peroxide intermediate species (*OOH) was obtained, and the effect of Ni on the interaction between surface Pt and *OOH was studied by varying the Ni content in the alloy. The frequency of the *OOH spectral band has an obvious red-shift with increasing Ni content. Combined with density functional theory (DFT) calculations, we show that Ni-doping can optimize *OOH surface binding on the Pt surface, achieving more efficient electron transfer, thus improving the ORR rate. Notably, these results evidence the SERS borrowing strategy as an effective technique for observations of catalytic processes.
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http://dx.doi.org/10.1021/jacs.0c12755DOI Listing
January 2021

Spectroscopic Verification of Adsorbed Hydroxy Intermediates in the Bifunctional Mechanism of the Hydrogen Oxidation Reaction.

Angew Chem Int Ed Engl 2021 Mar 29;60(11):5708-5711. Epub 2021 Jan 29.

State Key Laboratory of Physical Chemistry of Solid Surfaces,iChEM, College of Chemistry and Chemical Engineering, College of Energy, Xiamen University, Xiamen, 361005, China.

Elucidating hydrogen oxidation reaction (HOR) mechanisms in alkaline conditions is vital for understanding and improving the efficiency of anion-exchange-membrane fuel cells. However, uncertainty remains around the alkaline HOR mechanism owing to a lack of direct in situ evidence of intermediates. In this study, in situ electrochemical surface-enhanced Raman spectroscopy (SERS) and DFT were used to study HOR processes on PtNi alloy and Pt surfaces, respectively. Spectroscopic evidence indicates that adsorbed hydroxy species (OH ) were directly involved in HOR processes in alkaline conditions on the PtNi alloy surface. However, OH species were not observed on the Pt surface during the HOR. We show that Ni doping promoted hydroxy adsorption on the platinum-alloy catalytic surface, improving the HOR activity. DFT calculations also suggest that the free energy was decreased by hydroxy adsorption. Consequently, tuning OH adsorption by designing bifunctional catalysts is an efficient method for promoting HOR activity.
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http://dx.doi.org/10.1002/anie.202015571DOI Listing
March 2021

High-Efficiency Boiling Heat Transfer Interfaces Composed of Electroplated Copper Nanocone Cores and Low-Thermal-Conductivity Nickel Nanocone Coverings.

ACS Appl Mater Interfaces 2020 Sep 19;12(35):39902-39909. Epub 2020 Aug 19.

Functional Materials and Interfaces Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Science, Suzhou 215123, P. R. China.

We demonstrate that copper-based super-thin high-efficiency boiling heat transfer (BHT) interfaces can be obtained via electroplating hierarchical nickel nanocone coverings on the surface of copper nanocone cores. By regulating surface morphologies, wettability, and mass and heat transfer properties of hierarchical structures, we reveal the regulation rules of their performance. Based on this, we obtain the optimized BHT interfaces with a thickness of only 6.4 μm, which shows 228% enhancement in the maximal heat transfer coefficient, 71% enhancement in the critical heat flux, and 68% decrease in the superheat for the onset of nucleate boiling, as compared to the flat copper surface. Our studies clearly indicate that, although the in situ growth of nickel nanocones can unavoidably increase the interface thermal resistance of hierarchical structures, its optimization can still enhance BHT performance. This may be ascribed to the coupling of several interface effects such as more heat transfer area, more nucleation sites, smaller bubble departure sizes, and stronger liquid supply ability caused by hierarchical structures. Our work opens up a new avenue for the development of copper-based super-thin high-efficiency BHT interfaces, which would help enhance the efficiency of energy utilization and heat dissipation of various thermal devices.
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http://dx.doi.org/10.1021/acsami.0c10761DOI Listing
September 2020
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