Potential-driven surface active structure rearrangement over FeP@NC towards efficient electrocatalytic hydrogen evolution. Issue 15 (27th March 2019)

• Record Type: Journal Article
• Authors: Tang, Fumin; Su, Hui; Zhao, Xu; Zhang, Hui; Hu, Fengchun; Yao, Peng; Liu, Qinghua; Cheng, Weiren
• Is Part Of: Physical chemistry chemical physics. Volume 21:Issue 15(2019)
• Page Start: 7918
• Page End: 7923
• Publication Date: 2019-03-27
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c9cp00375d
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Understanding the variation of active structure during the hydrogen evolution reaction (HER) process is of great importance for aiding in the design of optimized electrocatalysts. Abstract : Understanding the variation of active structure during the hydrogen evolution reaction (HER) process is of great importance for aiding in the design of optimized electrocatalysts. Herein, we present a composite material of FeP nanoparticles coated by N-doped carbon (FeP@NC) as an efficient HER electrocatalyst, synthesized by a pyrolysis and equivalent-volume impregnation method. The as-prepared FeP@NC catalyst can accelerate the HER at a small overpotential of 135 mV with a current density of 10 mA cm −2 in acidic medium and also shows a robust long-term stability with a minor decay of about 10% of the initial current density after 15 h. Using in situ X-ray absorption spectroscopy (XAS), a potential-dependent surface rearrangement of a surface pentahedral Fe structure into an octahedral Fe moiety via surface hydroxylation is clearly observed during the HER process, resulting in a much higher electrocatalytic activity. The theoretical calculations further unveil that the rearrangement of the surface FeP5 (OH) octahedral structure could effectively trigger the adjacent P atoms to act as favorable proton acceptor sites towards improving the reaction kinetics of the Volmer step for efficient electrochemical hydrogen evolution.