Recently, the research group of Professor Chen Qianjin, a member of the intelligent health management team led by Professor Yi Tao at the College of Chemistry and Chemical Engineering, has made a significant breakthrough in the field of single-particle electrocatalysis. This work was recently published in the internationally renowned journal ACS Nano under the title "Spin-Polarization Tailored Oxygen Evolution of Chiral Gold Nanocrystals Probed by Single-Particle Electrochemistry."
The oxygen evolution reaction (OER) is a critical step in energy conversion technologies such as water electrolysis, yet its sluggish kinetics are primarily constrained by the complex four-electron transfer process and the singlet-triplet spin transition. The chiral-induced spin selectivity (CISS) effect, which enables spin polarization of electrons, holds promise for lowering the reaction energy barrier; however, how chiral morphology quantitatively influences catalytic activity remains unclear. In this work, D-type, L-type, and achiral gold nanocrystals (D Au I/II/III, L Au III, and Rac Au III) with precisely tunable helical degrees were first synthesized using chiral cysteine as a morphology-directing agent, and their morphological uniformity and size consistency were confirmed by scanning electron microscopy. Subsequently, their chiral optical activity and spin polarization were characterized by circular dichroism spectroscopy and magnetic-force-assisted atomic force microscopy (mc AFM), with spin polarization values reaching -70.6% and 68.9% for D Au III and L Au III, respectively. On this basis, single-particle OER currents were measured on individual nanocrystals using scanning electrochemical cell microscopy (SECCM).
Single-particle measurements revealed that the average OER currents of chiral D- and L-Au III (approximately 59 and 57 pA, respectively) were about 70% higher than that of achiral Rac Au III (approximately 34 pA). Moreover, the activity increased progressively with the helical degree from D Au I to D Au III, and one-way analysis of variance (ANOVA) confirmed that the activity differences were highly statistically significant (p < 0.001). More importantly, after normalization by particle surface area, the current densities of the three D-type particles exhibited a linear positive correlation with their respective spin polarization values, directly confirming that the CISS effect is the intrinsic origin of the catalytic enhancement. Macroscopic measurements validated the same trend; however, the single-particle approach circumvented aggregation and mass-transport limitations and revealed the inter-particle activity heterogeneity. This work establishes, for the first time at the single-particle level, a quantitative structure-activity relationship linking chiral morphology, spin polarization, and catalytic activity, thereby providing a new design strategy for developing efficient spin-selective electrocatalysts.
This work was supported by the National Natural Science Foundation of China. Zhou Huaxu, a Ph.D. candidate (Class of 2022) from the College of Chemistry and Chemical Engineering, is the first author of the paper. Professor Chen Qianjin is the corresponding author. Donghua University is the primary affiliation. The collaborators are Dr. Fang Yuxi and Dr. Zhang Wanning from Shanghai Jiao Tong University.
Original link to this article: 10.1021/acsnano.6c05258
Homepage of the research group：https://www.x-mol.com/groups/qianjinchen2105
