Zheng Hu’s group reports the correlation between heteroatom coordination and hydrogen evolution for single-site Pt on carbon-based nanocages in Angew.Chem.


Efficient, cost-effective, and stable electrocatalysts are crucial for the realization of hydrogen production via water electrolysis powered by renewable electricity. In recent years, carbon-supported platinum single-site catalysts (Pt SSCs) have shown remarkable performance in hydrogen evolution reaction (HER), but the intrinsic relationship between HER performance and the coordination structure of Pt SSC has not been systematically explored.

Recently, Prof. Zheng Hu's group constructed a series of Pt SSCs supported on hieratical carbon nanocages through the synergistic effect of micropore capture and heteroatom anchoring. The correlation between heteroatom coordination and the HER performance of Pt SSCs was systematically and deeply explored through a combination of experimental and theoretical study. From S coordination, P coordination, C coordination to N coordination, the Pt SSCs exhibited increasing HER activities, with overpotentials of 500, 97, 21, and 15 mV, respectively, at a current density of 10 mA cm-2 (Figure 1).

Figure 1. The morphologies and HER activities of Pt SSCs on hierarchical carbon-based nanocages.

The complete HER processes for this series of Pt SSCs were simulated by density functional theory. It was found that these Pt sites need to adsorb up to 5 H atoms before releasing hydrogen molecules/hydrogen evolution. The study also figured out that the reasonable descriptor for evaluating HER activity should be the adsorption energy of H atoms prior to hydrogen evolution, rather than the commonly used adsorption energy of the first H atom (Figure 2).

Figure 2. The multi-H-atom adsorption HER mechanism on four Pt SSCs.

Electronic structure analysis revealed that compared to P and S, N coordination significantly increases the density of states of the Pt 5d orbitals near the Fermi level, thereby facilitating electron transfer and proton capture during the HER process, leading to the highest HER activity (Figure 3).

Figure 3. Electronic structure simulation

The N-coordinated Pt SSC demonstrated excellent stability, with an increase of only 6.4 mV in overpotential at 50 mA cm-2 after a 10,000-cycle accelerated degradation test (ADT). Additionally, there was negligible drop in potential during a 24-hour chronopotentiometry measurements at a current density of 50 mA cm-2, indicating that the N-coordinated Pt single sites maintained kinetic stability throughout the multi-H-atom adsorption HER process (Figure 4). The progress of this study reveals the intrinsic correlation between the HER performance and the coordination structure of Pt SSCs, providing a significant guidance for the rational design of advanced Pt SSCs.

Figure 4. HER stabilities of four Pt SSCs and structural characterization after ADT.

The paper entitled “Correlation between Heteroatom Coordination and Hydrogen Evolution for Single-site Pt on Carbon-based Nanocages” was published in Angewandte Chemie International Edition on March 11th, 2024 (https://doi.org/10.1002/anie.202401304 DOI: 10.1002/anie.202401304). Prof. Zheng Hu, Prof. Qiang Wu and Prof. Lijun Yang are the corresponding authors. Ph.D. student Xueyi Cheng is the first author. This project was funded by the National Key Research and Development Program of China (No. 2021YFA1500900), the National Natural Science Foundation of China (Nos. 52071174, 21832003, and 21972061), the Natural Science Foundation of Jiangsu Province, Major Project (No. BK20212005), and the Foundation of Science and Technology of Suzhou (No. SYC2022102).