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Updated: Jan 11, 2026
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Published on: July 27, 2022
Regulation of Rh Single-Atom Coordination for Enhanced Reverse Hydrogen Spillover and Efficient Electrochemical
Qian Zheng1, Hengyue Xu2, Yancai Yao1
1State Key Laboratory of Green Papermaking and Resource Recycling, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
None:
Reverse hydrogen spillover (RHS) from the surface oxygen of titanium oxide to single-atom catalytic centers enables efficient electrochemical hydrogenation via atomic hydrogen (H*) transfer, a process critically dependent on the coordination environment and electronic structure of the active site. In this study, we reveal that a four-oxygen-coordinated Rh single-atom electrode (Rh1O4) exhibits superior RHS capability during water electrolysis of titanium foam compared to its five- or three-coordinated counterparts (Rh1O5 or Rh1O3). The Rh-O coordination number directly modulates the relative position of the Rh d-band center to the Fermi level, thereby regulating H* adsorption on Rh and the RHS efficiency between titanium oxide's surface oxygen and the Rh single atom on the titanium foam electrode. Remarkably, the four-coordinated Rh1O4 configuration achieves an optimized hydrogen adsorption Gibbs free energy (ΔGH*) of +0.08 eV, approaching that of the coordinating oxygen atoms (-0.47 eV), which drastically reduces the RHS energy barrier to +0.55 eV, significantly lower than those of Rh1O5 and Rh1O3. This structural optimization translates to exceptional electrochemical hydrogenation performance, exemplified by a 4-chlorophenol degradation rate constant of 4.65 h-1, surpassing Rh1O5 (1.18 h-1) and Rh1O3 (0.16 h-1) by 4- and 29-folds, respectively. Our findings highlight the pivotal role of single-atom coordination engineering in tailoring atomic-level hydrogen transfer dynamics and provide a strategic framework for designing high-performance single-atom electrocatalysts for sustainable electrochemical hydrogenation applications.
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