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Canonic‐Like HER Activity of Cr 1– x Mo x B 2 Solid Solution: Overpowering Pt/C at High Current Density
Author(s) -
Park Hyounmyung,
Lee Eunsoo,
Lei Ming,
Joo Hyunkeun,
Coh Sinisa,
Fokwa Boniface P. T.
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202000855
Subject(s) - overpotential , materials science , solid solution , transition metal , metal , lattice constant , electrochemistry , lattice (music) , hydrogen , crystallography , analytical chemistry (journal) , catalysis , thermodynamics , chemistry , physics , metallurgy , electrode , biochemistry , quantum mechanics , chromatography , diffraction , acoustics , optics
Abundant transition metal borides are emerging as substitute electrochemical hydrogen evolution reaction (HER) catalysts for noble metals. Herein, an unusual canonic‐like behavior of the c lattice parameter in the AlB 2 ‐type solid solution Cr 1– x Mo x B 2 ( x = 0, 0.25, 0.4, 0.5, 0.6, 0.75, 1) and its direct correlation to the HER activity in 0.5 M H 2 SO 4 solution are reported. The activity increases with increasing x , reaching its maximum at x = 0.6 before decreasing again. At high current densities, Cr 0.4 Mo 0.6 B 2 outperforms Pt/C, as it needs 180 mV less overpotential to drive an 800 mA cm −2 current density. Cr 0.4 Mo 0.6 B 2 has excellent long‐term stability and durability showing no significant activity loss after 5000 cycles and 25 h of operation in acid. First‐principles calculations have correctly reproduced the nonlinear dependence of the c lattice parameter and have shown that the mixed metal/B layers, such as (110), promote hydrogen evolution more efficiently for x = 0.6, supporting the experimental results.