posted on 2023-04-03, 12:37authored byNing Wang, Pengfei Ou, Rui Kai Miao, Yuxin Chang, Ziyun Wang, Sung-Fu Hung, Jehad Abed, Adnan Ozden, Hsuan-Yu Chen, Heng-Liang Wu, Jianan Erick Huang, Daojin Zhou, Weiyan Ni, Lizhou Fan, Yu Yan, Tao Peng, David Sinton, Yongchang Liu, Hongyan Liang, Edward H. Sargent
Acidic water electrolysis enables the production of hydrogen
for
use as a chemical and as a fuel. The acidic environment hinders water
electrolysis on non-noble catalysts, a result of the sluggish kinetics
associated with the adsorbate evolution mechanism, reliant as it is
on four concerted proton-electron transfer steps. Enabling a faster
mechanism with non-noble catalysts will help to further advance acidic
water electrolysis. Here, we report evidence that doping Ba cations
into a Co3O4 framework to form Co3–xBaxO4 promotes
the oxide path mechanism and simultaneously improves activity in acidic
electrolytes. Co3–xBaxO4 catalysts reported herein exhibit an
overpotential of 278 mV at 10 mA/cm2 in 0.5 M H2SO4 electrolyte and are stable over 110 h of continuous
water oxidation operation. We find that the incorporation of Ba cations
shortens the Co–Co distance and promotes OH adsorption, findings
we link to improved water oxidation in acidic electrolyte.