A research team led by Professor Bo Song from the Center for Composite Materials and Structure at the Harbin Institute of Technology (HIT), in collaboration with Professor Song Jin's group at the University of Wisconsin–Madison, has made significant progress in understanding the mechanisms of electrocatalytic water splitting.
The team pioneered the use of hydrogen isotope labeling combined with electrochemical analysis to precisely reveal the microscopic kinetics of proton transfer during water splitting. Their study, "Isotope-dependent Tafel analysis probes proton transfer kinetics during electrocatalytic water splitting", was recently published online in Nature Chemistry.
Hydrogen is widely regarded as a key energy carrier for achieving carbon neutrality, but the low efficiency of hydrogen production through water electrolysis remains a bottleneck. For decades, scientists have struggled to directly probe proton transfer at the electrode–solution interface.
By replacing hydrogen (H) with its stable isotope deuterium (D), the researchers utilized changes in vibrational energy and catalytic performance to track proton transfer barriers. They integrated isotope effects into a new isotope-dependent Tafel analysis model, enabling accurate identification of whether proton transfer is the rate-determining step.
This method overcomes the limitations of conventional kinetic isotope effect analysis and was validated on six hydrogen evolution catalysts and 21 oxygen evolution catalysts, demonstrating broad applicability. The results provide a new theoretical tool and evaluation standard for designing next-generation, high-efficiency electrolyzers.
HIT serves as the paper's first and corresponding institution. Professor Bo Song, Professor Song Jin, and Researcher Hongyuan Sheng of Fudan University are co-corresponding authors. Jinzhen Huang, a PhD graduate from HIT, is the first author.
The research was supported by the National Natural Science Foundation of China, the Ministry of Education's frontier science center program, Heilongjiang province's "Leading Goose" project, and HIT's Zhengzhou Research Institute.