Chaoyi Yan

A New Member of Electrocatalysts Based on Nickel Metaphosphate Nanocrystals for Efficient Water Oxidation

High-performance electrocatalysts are desired for electrochemical energy conversion, especially in the field of water splitting. Here, a new member of phosphate electrocatalysts, nickel metaphosphate (Ni2 P4 O12 ) nanocrystals, is reported, exhibiting low overpotential of 270 mV to generate the current density of 10 mA cm-2 and a superior catalytic durability of 100 h. It is worth noting that Ni2 P4 O12 electrocatalyst has remarkable oxygen evolution performance operating in basic media. Further experimental and theoretical analyses demonstrate that N dopant boosts the catalytic performance of Ni2 P4 O12 due to optimizing the surface electronic structure for better charge transfer and decreasing the adsorption energy for the oxygenic intermediates.

High-Performance SERS Substrate Based on Hierarchical 3D Cu Nanocrystals with Efficient Morphology Control

Cu nanocrystals of various shapes are synthesized via a universal, eco-friendly, and facile colloidal method on Al substrates using hexadecylamine (HDA) as a capping agent and glucose as a reductant. By tuning the concentration of the capping agent, hierarchical 3D Cu nanocrystals show pronounced surface-enhanced Raman scattering (SERS) through the concentrated hot spots at the sharp tips and gaps due to the unique 3D structure and the resulting plasmonic couplings. Intriguingly, 3D sword-shaped Cu crystals have the highest enhancement factor (EF) because of their relatively uniform size distribution and alignment. This work opens new pathways for efficiently realizing morphology control for Cu nanocrystals as highly efficient SERS platforms.

Cytomembrane-Structure-Inspired Active Ni-N-O Interface for Enhanced Oxygen Evolution Reaction

Surface/interface design is one of the most significant and promising motivations to develop high-performance catalysts for electrolytic water splitting. Here, the nature of cytomembrane having the most effective and functional surface structure is mimicked to fabricate a new configuration of Ni-N-O porous interface nanoparticles (NiNO INPs) with strongly interacting nanointerface between the Ni3 N and NiO domains, for enhancing the electrocatalytic oxygen evolution reaction (OER) performance. The combination of transmission electron microscopy and electrochemical investigations, tracking the correlation between microstructure evolution and catalytic activity, demonstrate the strongly coupled nanointerface for an approximately sixfold improvement of electrolytic efficiency. Density functional theory simulates the electrocatalytic process with a maximum of 85% reduction of the energy barrier. Further investigations find that the real active site for the OER in the NiNO INPs is the strongly coupled Ni-N-O nanointerface, not the derived amorphous hydroxide, during the OER process. The determination of the correlation of constructed nanointerface with catalytic properties suggests a significant strategy toward the rational design of catalysts for efficient water electrocatalysis.