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In situ phase transformation on nickel-based selenides for enhanced hydrogen evolution reaction in alkaline medium

DOI: 10.1021/acsenergylett.0c01385 DOI Help

Authors: Lingling Zhai (Hong Kong Polytechnic University) , Tsz Woon Benedict Lo (The Hong Kong Polytechnic University) , Zheng-Long Xu (The Hong Kong Polytechnic University) , Jonathan Potter (Diamond Light Source) , Jiaying Mo (University of Oxford) , Xuyun Guo (The Hong Kong Polytechnic University) , Chiu Chung Tang (Diamond Light Source) , Shik Chi Edman Tsang (University of Oxford) , Shu Ping Lau (The Hong Kong Polytechnic University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Energy Letters

State: Published (Approved)
Published: July 2020
Diamond Proposal Number(s): 23230

Abstract: Identification of the active species in electrocatalysts toward hydrogen evolution reaction (HER) is of great significance for the development of the catalytic industry; however, it is still the subject of considerable controversy. Herein, we applied operando synchrotron X-ray powder diffraction (SXRD) in the NiSe2 electrocatalyst system, and an in situ phase transformation from cubic NiSe2 to hexagonal NiSe was revealed. The NiSe phase showed an enhanced catalytic activity. Operando Raman spectroscopy verified the decomposition of NiSe2 during HER. Theoretical calculations suggested that the charge transfers from the Se site to Ni site during this evolution process, leading to an increased conductivity and a shifting up of d-band center, which is attributed to the enhanced activity. The generated NiSe phase acts as the “real” active species. Our work unravels the underlying phase transition of the electrocatalyst on reductive conditions in alkaline medium and highlights the significance of identifying the intrinsic active sites under realistic reaction conditions.

Journal Keywords: Catalysts; Physical and chemical processes; Evolution reactions; Transmission electron microscopy; Phase transitions

Subject Areas: Chemistry, Energy

Instruments: I11-High Resolution Powder Diffraction

Added On: 13/07/2020 09:14

Discipline Tags:

Earth Sciences & Environment Sustainable Energy Systems Energy Climate Change Physical Chemistry Catalysis Chemistry

Technical Tags:

Diffraction X-ray Powder Diffraction