Zhijun Wang,Jingjing Wu,Limin Liu,Wenchi Wu,Yinfeng Wang,Haigen Huang,Fei Deng,Xuexia Liu
Currently, platinum (Pt)/carbon support composite materials have tremendous application prospects in the hydrogen evolution reaction (HER). However, one of the primary challenges for boosting their performance is designing a substrate with the desired microstructure. Herein, the intact hollow carbon spheres (HCSs) were prepared via template method. Based on the morphology variation of the as-prepared HCSs-x, we conjectured that the polydopamine (PDA) core was generated first and then slowly grew into a complete overburden (SiO2@PDA). Afterward, Pt atomic clusters were anchored on the outer shells of HCSs-4 to construct composite electrocatalysts (Pty/HCSs-4) by a chemical reduction method. Due to the low charge-transfer resistance, the HCSs have a large electrochemical surface area and provide a continuous electron transport pathway, boosting the atom utilization efficiency during hydrogen production and release. The synthesized Pt2.5/HCSs-4 electrocatalysts exhibit excellent HER activity in acidic media, which can be ascribed to the compositional modulation and delicate structural design. Specifically, when the overpotential is 10 A g–1, the overpotential can achieve 92 mV. This work opens a new route to fabricate Pt-based electrocatalysts and brings a new understanding of the formation mechanism of HCSs.
The application of layered molybdenum disulfide (MoS 2 ) in catalytic hydrogen production has attracted great interest, while their catalytic properties are limited by poor electron conductivity and a few catalytically active sites. In this work, we demonstrated a highly active electrocatalyst for large-scale hydrogen production, consisting of two-dimensional (2D) Pt-MoS 2 nanosheets along one-dimensional (1D) cobalt nanoparticle integrated carbon hollow nanofibers (Co@CHNF). The as-prepared Pt-MoS 2 -Co@CHNF had a large specific surface area (44.5 m 2 g −1 ). X-ray photoelectron spectrometer (XPS) and spherical aberration corrected transmission electron microscope (AC-STEM) demonstrated that Pt atomic clusters (Pt ACs) were doped on MoS 2 nanosheets by thermodynamically induced spontaneous interfacial redox between MoS 2 and H₂PtCl₆. The Pt-MoS 2 -Co@CHNF based catalysts exhibited an overpotential as low as 91 mV for 10 mA cm −2 and 258 mV for 200 mA cm −2 in 1 M KOH electrolyte, and there is no significant floating for catalytic active with 14 h continuous operation, which demonstrates its excellent long-term operation durability, significantly superior to the previously reported state-of-the-art Co-based or Mo-based catalysts. In particular, the self-supporting binder-free Pt-MoS 2 -Co@CHNF catalyst-based electrode showed an ultra-high current density of 500 mA cm −2 at a low overpotential of 301 mV, without any decrease after 24 h operation at 500 mA cm −2 in 1 M KOH seawater electrolyte, representing a great potential for large-scale seawater hydrogen production.
Junwei Liang,Yuxiang Liu,Rongzheng Liu,Sufan Zheng,Zhichun Si,Duan Weng,Feiyu Kang
Preparing stable highly dispersed Pt based electrocatalyst is promising to reduce material expense of H 2 product via electrocatalytic water splitting. However, it is still a great challenge to obtain stable single atomic Pt catalysts which can be applied in acidic electrolyte. In the present work, we synthesized Pt atomic clusters on carbon quantum dots (CQDs) grafting multiwall carbon nanotube (CNT) (Pt content: 1 wt.%) catalysts and then loading the catalysts on carbon cloth (Pt content: 0.01 mg▪cm –2 ) for activity test. The overpotential of 29 mV versus RHE was obtained over 1%Pt/CQDs/CNT catalysts at the current density of 10 mA▪cm –2 , and the Tafel slope of 22 mV decade –1 was obtained, too. Especially, the catalysts showed significant stability in hydrogen evolution reactions (HER) in acidic solution, of which the overpotential was still smaller than that of 20%Pt/C after 10,000 CV cycles. CQDs provided coordinating sites for dispersing Pt atomic clusters and improved the H + concentration in adjacent area around the Pt clusters. This method provides a general strategy to design the highly efficient electrocatalysts with ultra-low precious metals for H 2 evolution in acidic electrolyte.
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