Search

Synthesizing and designing of the hydrogen evolution reaction (HER) electrode composed of earth-abundance elements is the current research topics. Among the many discovered catalysts, cobalt disulfide has outstanding performance for HER due to its catalytic activity cobalt sites. Here, phosphorus-doped cobalt disulfide (P doped CoS 2 ) samples are successfully synthesized via simple one-step hydrothermal method. By using them as the electrocatalysts, the most efficient electrode we obtained shows the excellent electrocatalytic activity, with low overpotential of 53 mV to achieve a 10 mA/cm 2 current density, a small Tafel slope of 57 mV/dec and a high stability after 10000 cycles. First-principle calculations results indicate that phosphorus dopants could improve the electrocatalytic activity of hydrogen evolution by lowing the free energy for atomic hydrogen adsorption ( Δ G H * ) at the Co sites. Moreover, the metallic P doped CoS 2 could promote electron transfer and offers faster HER kinetics, thereby leading to better HER activity. This finding demonstrates an effective way to synthesis nonmetal doped CoS 2 catalysts via one-step hydrothermal method and further improve the HER performance of CoS 2 under the guidance of theoretical calculations. [ABSTRACT FROM AUTHOR]

How to balance the active sites and conductivity for electrocatalysts in hydrogen evolution reaction (HER) is still a challenge. In this paper, we reported the enhanced catalytic activeties of metal-phase assisted 1T@2H-MoSe 2 nanosheets for hydrogen evolution. Combining with the structure analysis and electrochemical measurement results, we concluded that the incorporation of 1T metal phase into its 2H matrix could increase the electro conductivity of the catalysts and yield more active sites due to the atom-rearrangement in the phase transformation progress. An HER electrode with low onset potential of 20 mV and small Tafel slope of 41 mV/dec were obtained for 1T@2H-MoSe 2 nanosheets with the optimized active sites and conductivity. This work can broaden our horizons in the design of new highly efficient catalysts for hydrogen evolution. [ABSTRACT FROM AUTHOR]

[Display omitted] • A weak-strong coetching strategy is developed for metal–organic frameworks. • Hollow nanopompoms structure is obtained and can be maintained upon pyrolysis. • Pyrolyzed nanopompoms allow for efficient electron transfer applications. • Heterophases increase active sites and promotes electrocatalytic performance. • Nanopompoms catalyst has desirable bifunctional performance for Zn-air batteries. The rational structure and composition design of bifunctional electrocatalysts for oxygen evolution reactions (OER) and oxygen reduction reactions (ORR) is crucial for rechargeable metal–air batteries. Here, we report controlled structural transitions of metal–organic frameworks through a weak-strong competitive coordination strategy for high-performance electrocatalysts. Upon the introduction of potassium ferricyanide (PF) and/or phosphomolybdic acid (POM), cubic zeolitic-imidazole framework-67 (Cube-67) undergoes both chemical and macroscopic morphology changes, i.e., from nanocubes to hollow nanopompoms, where PF and POM act as the weak chelator (i.e., for finer structures) and the strong chelator (i.e., shape-directing agent), respectively. After calcination, the hierarchically structured nanopompoms display tunable and high-performance OER and ORR catalytic activities suitable for Zn–air batteries that display a long-term charge–discharge cycling stability. This work not only holds promise for clean-energy applications but provides a design principle for engineering advanced electrocatalysts by effectively tuning their structural and chemical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • A weak-strong coetching strategy is developed for metal–organic frameworks. • Hollow nanopompoms structure is obtained and can be maintained upon pyrolysis. • Pyrolyzed nanopompoms allow for efficient electron transfer applications. • Heterophases increase active sites and promotes electrocatalytic performance. • Nanopompoms catalyst has desirable bifunctional performance for Zn-air batteries. The rational structure and composition design of bifunctional electrocatalysts for oxygen evolution reactions (OER) and oxygen reduction reactions (ORR) is crucial for rechargeable metal–air batteries. Here, we report controlled structural transitions of metal–organic frameworks through a weak-strong competitive coordination strategy for high-performance electrocatalysts. Upon the introduction of potassium ferricyanide (PF) and/or phosphomolybdic acid (POM), cubic zeolitic-imidazole framework-67 (Cube-67) undergoes both chemical and macroscopic morphology changes, i.e., from nanocubes to hollow nanopompoms, where PF and POM act as the weak chelator (i.e., for finer structures) and the strong chelator (i.e., shape-directing agent), respectively. After calcination, the hierarchically structured nanopompoms display tunable and high-performance OER and ORR catalytic activities suitable for Zn–air batteries that display a long-term charge–discharge cycling stability. This work not only holds promise for clean-energy applications but provides a design principle for engineering advanced electrocatalysts by effectively tuning their structural and chemical properties. [ABSTRACT FROM AUTHOR]