Synergistic effect between undercoordinated platinum atoms and defective nickel hydroxide on enhanced hydrogen evolution reaction in alkaline solution

• Published in: Nano energy 2018-06, Vol.48, p.590-599
• Main Authors: Wang, Yao, Zhuo, Hongying, Zhang, Xin, Dai, Xiaoping, Yu, Kuomiao, Luan, Chenglong, Yu, Lei, Xiao, Yun, Li, Jun, Wang, Meiling, Gao, Fei
• Format: Article
• Language: English
• Subjects: Defective nickel hydroxide nanosheets; Density functional theory calculations; Platinum-manganese/nickel hydroxide catalyst; Undercoordinated Pt atoms; Water dissociation
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2018.03.080

Improving the hydrogen evolution reaction (HER) performance of Pt based catalysts in alkaline environment is of key importance in various industrial processes and remains a challenge so far. Given the lower energy barriers of water dissociation upon the undercoordinated Pt and oxophilic species, engineering Pt based catalysts possessed the high density of surface atomic steps, ledges, and kinks with Ni(OH)2 are an effective way to endow Pt with high catalytic HER activity. Based on density functional theory (DFT) models, we demonstrated that the energy barrier of water dissociation process could be significantly reduced by the synergistic effect of undercoordinated Pt atoms and defective Ni(OH)2. This hypothesis has been further validated by experimental results that concave nanocube (CNC) Pt-Mn particles exposed by high indexed facets (HIFs) supported on the Ni(OH)2 nanosheets exhibited 6.88 times specific current density (4.80 times mass current density) higher than nanocube Pt-Mn particles mainly exposing non-defective surface. Moreover, the in situ electrochemical etching experiments suggested that the enhanced HER performance was attributed to the synergistic effect of Ni(OH)2 and Pt, rather than the increase of active sites for Pt via calculating the electrochemical surface area (ECSA) values. Thus, this work provides an insight for rational design of Pt based nanocomposite with enhanced catalytic properties for alkaline HER under the guidance of computational modeling. The synergistic effect between undercoordinated Pt atoms and defective Ni(OH)2 nanosheets has an benefit on water dissociation in alkaline solution, in which the specific current density (mass current density) of concave cube (CNC) Pt-Mn/Ni(OH)2 for HER is 6.88 (4.80) times higher than that of nanocube Pt-Mn catalyst. [Display omitted] •The undercoordinated Pt atoms has a benefit on higher HER performance, resulting from lower energy barrier for water dissociation.•The HER performance in basic solution can be further enhanced at the interface of undercoordinated Pt atoms and defective Ni(OH)2 by reducing water dissociation barrier.•Introduction of moderate Ni(OH)2 nanosheets can inspire the activity of Pt on HER.