RESUMO
Surface engineering offers opportunities for the design and synthesis of Pt-based alloyed electrocatalysts with high mass activity and resistance to CO poisoning, which is of great significance for methanol electrooxidation. Surface curvature regulation may endow electrocatalysts with enhanced atomic utilization and abundance of unsaturated atoms; however, a reliable synthetic route for controlled construction of tailorable curved surface is still lacking. Here, a colloidal-chemical method to synthesize two types of PtCu branched-structured electrocatalysts, where the concave curvature can be customized is reported. These studies show that, among various synthesis parameters, the concentration of CuCl2 ·2H2 O precursor is the key factor in manipulating the reaction kinetics and determining the concave surface curvature. Significantly, PtCu branched nanocrystals with long and sharp arms (PtCu BNCs-L), featuring a high concave surface curvature, exhibit remarkable activity and stability toward MOR, which is mainly attributed to advanced features of a highly concave surface and the synergistically bifunctional effect from introduced oxophilic Cu metal. In situ Raman spectroscopy and CO stripping test demonstrates weakened CO adsorption and accelerated CO removal on PtCu BNCs-L. This work highlights the importance of surface curvature, opening up an appealing route for the design and synthesis of advanced electrocatalysts with well-defined surface configurations.
RESUMO
Dual-confined porous Si@c-ZIF@carbon nanofibers (Si@c-ZIF@CNFs) are fabricated that possess excellent antioxidant capacity, high surface area and abundant pores, which enhances conductivity, relieves volume expansion and facilitates electrolyte penetration during cycling. When evaluated as self-supporting anodes for lithium-ion batteries, the Si@c-ZIF@CNFs exhibit excellent cycling and rate performance.
