Park Hyounmyung, Lee Eunsoo, Lei Ming, Joo Hyunkeun, Coh Sinisa, Fokwa Boniface P T
Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA, 92521, USA.
Department of Chemistry, University of California, Riverside, Riverside, CA, 92521, USA.
Adv Mater. 2020 Jul;32(28):e2000855. doi: 10.1002/adma.202000855. Epub 2020 Jun 3.
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 -type solid solution Cr Mo B (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 SO solution are reported. The activity increases with increasing x, reaching its maximum at x = 0.6 before decreasing again. At high current densities, Cr Mo B outperforms Pt/C, as it needs 180 mV less overpotential to drive an 800 mA cm current density. Cr Mo B 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.
大量的过渡金属硼化物正成为贵金属的替代电化学析氢反应（HER）催化剂。在此，报道了AlB型固溶体CrₓMo₁₋ₓB（x = 0、0.25、0.4、0.5、0.6、0.75、1）中c晶格参数的一种不寻常的类规范行为及其与0.5 M H₂SO₄溶液中HER活性的直接相关性。活性随x的增加而增加，在x = 0.6时达到最大值，然后再次下降。在高电流密度下，Cr₀.₆Mo₀.₄B优于Pt/C，因为它在驱动800 mA cm⁻²电流密度时所需的过电位比Pt/C少180 mV。Cr₀.₆Mo₀.₄B具有出色的长期稳定性和耐久性，在酸性条件下运行5000次循环和25小时后没有明显的活性损失。第一性原理计算正确地再现了c晶格参数的非线性依赖性，并表明混合金属/B层，如（110），对于x = 0.6能更有效地促进析氢，这支持了实验结果。
