Low-cost preparation of durable electrocatalysts is vital for energy storage and conversion. Here, we integrated two methods of synthesizing isolated iron atoms into a special carbon matrix as an advanced electrocatalyst. Atomic Fe isolation and graphene nanomeshes or curved carbon nanoshells were almost synthesized simultaneously. The hierarchical atomic Fe/carbon material with 0.53 atom % Fe exhibited superior oxygen reduction reaction (ORR) performance to Pt–C (20 wt % Pt) with 40 mV more positive onset potential, larger current density, and stronger methanol-tolerant capability. We demonstrated that the catalytic active sites were Fe isolation and coordinated with nitrogen in the porous curved carbon-graphene matrix. This strategy could be developed into a general approach to prepare atomic metal/carbon electrocatalysts.

Hetero-layered iron–nitrogen coordination between g-C3N4 and graphene nanomeshes was developed for superior electrocatalytic activity in the oxygen reduction reaction.

The high diffusion rate of sulfur with respect to metal oxide creates precursors that deviate from the stoichiometric ratio, leading to poor growth controllability and defects in the as-grown transition metal dichalcogenides (TMDCs). The introduction of a sulfur precursor with a high melting point is a hopeful strategy to solve these problems. Here, we first introduce sodium sulfate (Na 2 SO 4 ) as a sulfur precursor, which plays roles in tuning diffusion of source precursors and balancing their mass flux based on the temperatureconfined decomposition of Na 2 SO 4 . We deduced the specific growth process by characterizing the composition of intermediates; the results show that emissions of sulfur and metal sources were synchronously released and spanning the entire growth stage. This temperature-controlled source-feeding system reduced the diffusion gap between sulfur and metal, which promoted a faster kinetics for reactions. Moreover, this method has the wide applicability for producing other TMDCs.

It is challenging to realize a dual-ion mode of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for detecting small molecules. Herein, graphene coated by porous amorphous carbon with P−O surface group and codoped by phosphorus and nitrogen (O−P,N-C/G) was synthesized from an aerogel formed by phytic acid, polyaniline, and electrochemically exfoliated graphene. The carbon material synthesized has the feature of large surface area (583 m 2 /g), good electrical conductivity, strong UV absorption, heteroatom doping, and surface functional groups suitable for laser-induced desorption/ionization. It was employed as a novel matrix suitable for both positive-ion and negative-ion modes in MALDI-TOF MS for the analysis of various small molecules including amino acids, small peptides, saccharides, drugs, and environmental pollutants, significantly outperforming control materials and a traditional CHCA (α-cyano-4hydroxycinnamic acid) or 2,5-dihydroxybenzoic (DHB) matrix. Remarkably, the detection limit of the anticancer drugs (5fluorouracil and ellagic acid) reaches 50 pmol. In addition, nice MALDI-TOF MS images can be mapped to detect mixed amino acids corresponding to homogeneous distribution of ion intensity. The monosaccharides and disaccharides can be distinguished by using the new matrix. Last but not least, it can be used to quantitatively detect glucose in human serum and soft drinks (glucose/fructose, 203.1 mM) without adding standards.

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