Thermal migration towards constructing W-W dual-sites for boosted alkaline hydrogen evolution reaction

Zhigang Chen,Shan Cong,Rui Gao,Xian-Zi Dong ,Ge Song,Chunyin Zhu ,Jingyuan Ma,Jian Chen,Hao Li,Xingxing Gan,Lu Wang,Ning Yang ,Zhigang Zhao,Dan Luo,Zhi-Yun Li ,Zhongmiao Gong,Ding Ding,Yishen Xu ,Wei Wei,Yi Cui

doi:10.1038/s41467-022-28413-6

Abstract

Tungsten carbides, featured by their Pt-like electronic structure, have long been advocated as potential replacements for the benchmark Pt-group catalysts in hydrogen evolution reaction. However, tungsten-carbide catalysts usually exhibit poor alkaline HER performance because of the sluggish hydrogen desorption behavior and possible corrosion problem of tungsten atoms by the produced hydroxyl intermediates. Herein, we report the synthesis of tungsten atomic clusters anchored on P-doped carbon materials via a thermal-migration strategy using tungsten single atoms as the parent material, which is evidenced to have the most favorable Pt-like electronic structure by in-situ variable-temperature near ambient pressure X-ray photoelectron spectroscopy measurements. Accordingly, tungsten atomic clusters show markedly enhanced alkaline HER activity with an ultralow overpotential of 53 mV at 10 mA/cm2 and a Tafel slope as low as 38 mV/dec. These findings may provide a feasible route towards the rational design of atomic-cluster catalysts with high alkaline hydrogen evolution activity.

Highlights

VII, III: W-C 4f7/2̹4f5/2 II, IV: W-C(O) 4f7/2̹4f5/2V, VI: W-O 4f7/2̹4f5/2 III I V IV II 500 ¥ 450 ¥ 400 ¥ InitialBinding energy
W-SAs anchored on the P-doped carbon material were obtained by pyrolyzing the W precursors at 700 °C for 2 h under an Ar atmosphere, followed by the alkaline leaching in a 6 M KOH solution for 3 days
In summary, by monitoring the evolution of the electronic structure of tungsten species from W-SAs to large-sized WC NPs using in situ variable-temperature near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) measurements, we confirmed that W-ACs with Pt-like electronic structure can be synthesized using W-SAs as the parent materials via a thermal migration strategy

Summary

Results

In the Raman spectra of W-SAs and W-ACs, only peaks at around 1341 and 1585 cm−1 are observed, which can be attributed to the characteristic D and G bands of the underlying carbon layer, respectively, whereas WC NPs show a broad band corresponding to the W-C stretching mode at around 800 cm−1 (Supplementary Fig. 3b)[10], implying that the atomically dispersed tungsten species aggregated into crystalline WC NPs after treatment at higher temperatures. The corresponding valence bands of the tungsten species were recorded to evaluate the Pt-like electronic structure obtained in the synthesized W-ACs. To facilitate comparison, the valence bands of single-crystalline Pt (111) and W foil were measured, and the valence bands of bare Ni foam and pristine P-doped carbon materials coated with Ni foam (C@Ni foam) were collected to eliminate any interference of the substrates (Supplementary Fig. 13). All tungsten species exhibit typically metallic feature with valence band profiles crossing the Fermi level, where a Ar etching

Background

V IV II

Discussion

Methods