Xiao Gu

Strengthened Synergistic Effect of Metallic MxPy (M = Co, Ni, and Cu) and Carbon Layer via Peapod-Like Architecture for Both Hydrogen and Oxygen Evolution Reactions

The smooth electric transmission is crucial for the high-efficient electrocatalysis. Herein, a series of peapod-like metallic Mx Py /C (M = Co, Ni, and Cu) composites is developed as bifunctional catalysts toward hydrogen and oxygen evolution reactions. For the first time, the metallic property of Cu3 P is confirmed through the theoretical calculation. The in-depth composition, structural and catalytic mechanism analysis of Mx Py /C discloses that the comparable activity and considerable durability of these catalysts mainly result from the strengthened synergistic effect between metallic Mx Py and carbon layer based on the unique peapod-like architecture. Especially, the atomic contact between Mx Py and carbon not only provides an open channel for electronic transmission but also ensures the integrity of peapod-like structure. Furthermore, the high electric conductivity of the inner metallic Mx Py and the outer carbon layer endows the Mx Py /C catalyst with rapid charge migration during the electrocatalytic pathway. These findings shed light on the origin of high catalytic activity of Mx Py /C and open a path for purposefully rationally synthesizing superior electrocatalysts.

Ganoderma‐Like MoS 2 /NiS 2 with Single Platinum Atoms Doping as an Efficient and Stable Hydrogen Evolution Reaction Catalyst

Herein, a unique ganoderma-like MoS2 /NiS2 hetero-nanostructure with isolated Pt atoms anchored is reported. This novel ganoderma-like heterostructure can not only efficiently disperse and confine the few-layer MoS2 nanosheets to fully expose the edge sites of MoS2 , and provide more opportunity to capture the Pt atoms, but also tune the electronic structure to modify the catalytic activity. Because of the favorable dispersibility and exposed large specific surface area, single Pt atoms can be easily anchored on MoS2 nanosheets with ultrahigh loading of 1.8 at% (the highest is 1.3 at% to date). Owing to the ganoderma-like structure and platinum atoms doping, this catalyst shows Pt-like catalytic activity for the hydrogen evolution reaction with an ultralow overpotential of 34 mV and excellent durability of only 2% increase in overpotential for 72 h under the constant current density of 10 mA cm-2 .

Selectively anchoring Pt single atoms at hetero-interfaces of γ-Al2O3/NiS to promote the hydrogen evolution reaction

Single-atom doping plays a vital role in catalysis by maximally taking advantage of atom efficiency. Herein, we report for the first time a new concept of selective single-atom doping with high loading via the crystal-lattice mismatch of a multicomponent hetero-nanostructure. Hetero-nanostructures, with exceptional properties, bring numerous vacancy defects or voids in the hetero-interfaces between the two different components, which can trap more atoms. In this work, single Pt atoms with an ultrahigh loading density of 2.8 wt% are selectively anchored on NiS in a three-dimensional flower-like NiS@Al2O3 heterostructure. This novel strategy can be expanded to a series of transition metal sulfide (TMS, NiS2, CoS2, and MnS) composites with large crystal-lattice mismatch. Pt atom doping remarkably enhances the catalytic performance. The Pt/NiS@Al2O3 exhibits an extremely high catalytic activity in the hydrogen evolution reaction, with a low overpotential of 34 mV and an excellent stability with a 2% increase in overpotential following 120 h under a constant density of 10 mA cm−2.

Thickness-tunable core–shell Co@Pt nanoparticles encapsulated in sandwich-like carbon sheets as an enhanced electrocatalyst for the oxygen reduction reaction

Despite enthusiastic research for platinum-based catalysts in past decades, these catalysts still lack long-term durability for the oxygen reduction reaction due to etching of the nonprecious metal in acidic electrolytes. Herein, we report a facile method for compounding two-dimensional sandwich-like Co/C samples with a series of different thicknesses of Pt layers, based on a seed-mediated growth method in chloroplatinic acid solution. There is only a 12.7% specific activity loss after 40 000 potential cycles. The sample exhibits super-high durability activity compared with other CoPt alloy catalysts under the same test conditions, benefiting from a great carbon layer maskant and Pt shell protection. According to density functional theory calculations, the nonprecious metal core has an indispensable role in adjusting the surface Pt atom and enhancing the activity for the oxygen reduction reaction. Our studies represent a robust method to design a core–shell structure with an ultralow content of Pt and improve the oxygen reduction reaction activity by tuning the nanoparticle architecture.