Yali Ma

Amino acids-incorporated nanoflowers with an intrinsic peroxidase-like activity.

Functional molecules synthesized by self-assembly between inorganic salts and amino acids have attracted much attention in recent years. A simple method is reported here for fabricating hybrid organic–inorganic nanoflowers using copper (II) ions as the inorganic component and natural amino acids as the organic component. The results indicate that the interactions between amino acid and copper ions cause the growth of the nanoflowers composed by C, N, Cu, P and O elements. The Cu ions and Cu(AA)n complexes containing Cu-O bond are present in the nanoflowers. The nanoflowers have flower-like porous structure dominated by the R groups of amino acids with high surface-to-volume ratios, which is beneficial for exerting its peroxidase-like activity depending on Fenton-like reaction mechanism with ABTS and Rhodamine B as the substrates. It is expected that the nanoflowers hold great promise as enzyme mimics for application in the field of biosensor, bioanalysis and biocatalysis.

Sprout-like Growth of Mesoporous Mo2C/NC Nanonetworks as Efficient Electrocatalyst for Hydrogen Evolution

Owing to their high surface areas, porous networks, nanosized walls, and unique electronic structure, mesoporous metal carbides with tailored nanoarchitectures are of particular interest for their prominent potential applications in various fields, including energy storage, fuel cells, and catalysis. Herein, we report a sprout‐like growth strategy for the preparation of a mesoporous β‐Mo2C nanonetwork embedded in a nitrogen‐rich carbon matrix. The nanoarchitecture can be tailored from a mesoporous Mo2C nanonetwork film into Mo2C nanoparticles embedded into the carbon layer. The as‐prepared β‐Mo2C material was demonstrated to drive a current density of 10 mA cm−2 at a low overpotential of 140 mV for the hydrogen evolution reaction (HER) in acidic conditions and to remain stable for at least 120 h. The excellent electrocatalytic performance may be from (1) mesoporous Mo2C frameworks offering numerous accessible active sites; (2) a carbon layer that protects the Mo2C from accumulation and favors electron transportation; and (3) shortened diffusion paths and ultrafine crystallinity that benefit its catalytic performance.

Core–shell structured hierarchically porous NiO microspheres with enhanced electrocatalytic activity for oxygen evolution reaction

The design and synthesis of efficient catalysts to substitute the currently effective and sturdy electrocatalysts composed of precious metal-based materials (e.g., IrO2 and RuO2) for the oxygen evolution reaction (OER) is still a huge challenge. In this regard, nickel-based OER catalysts with specific properties have drawn widespread attention. Herein, we prepared core–shell structured hierarchically mesoporous NiO microspheres through the thermal decomposition of Ni(OH)2 microspheres, which were synthesized through a one-pot hydrothermal method. The obtained NiO microspheres possess numerous mesopores, a high BET surface area, and 2D nanosheet-like shells, which largely promote mass/charge transportation and reduce ion transport pathways. By increasing the molar ratio of HMTA/Ni2+, the thickness of the outer nanosheet-like shell can be varied in the range of 0–35 nm. In particular, the NiO-300/r = 2 microspheres possess excellent properties for OER (overpotential of 360 mV to reach 10 mV cm−2), compared with previously-reported Ni-based materials. Furthermore, improved activity with an overpotential of 340 mV was reached by introducing Co.

Mesoporous Metal Oxide Encapsulated Gold Nanocatalysts: Enhanced Activity for Catalyst Application to Solvent-Free Aerobic Oxidation of Hydrocarbons

Here, we present a series of experimental studies to encapsulate ultrasmall gold nanoparticles into mesoporous metal oxide via an in situ self-assembly method. Notably, the 2.0Au@mZnO catalyst (∼2.0 nm gold nanoparticles loading on mesoporous ZnO nanospheres) shows excellent catalytic activity for indane oxidation (120 °C, conversion 88.5%) and affords much high turnover frequencies (9521 h-1). The catalytic activity of these gold-based catalysts was found to be correlated with the size of gold nanoparticles and the types of metal oxide supports. With a decrease in gold nanoparticle size, the catalytic conversion efficiency of indane oxidation increased. In addition, such catalysts possessed high thermal and chemical stability and could be reused more than 10 times without a remarkable loss of catalytic activity.

A general synthesis of abundant metal nanoparticles functionalized mesoporous graphitized carbon

The abundant transition metal and carbon sources allow imaginative combinations to design porous functional metal–carbon composites for wide applications. However, cumbersome and restricted methods seriously limit the development of mesoporous metal–carbon composites. In this study, a general coordination–polymerization method is reported to construct metal–gallic acid resin, and mesoporous carbon with highly dispersed metal nanoparticles and high metal nanoparticle concentration up to 20 wt%. The metal element composited with polymer and carbon can be various transition metals containing Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. Furthermore, the general strategy can be expanded to the fabrication of N doped bimetallic catalyst FeCo–MCN-900, which shows comparable electrocatalytic activity and higher stability compared to commercial Pt/C.