Controlled synthesis of mesoporous carbon with ultra-high N‐doping structure from polymer precursor for efficient electrocatalysis of oxygen reduction

Fe3O4 nanoparticles entrapped in the inner surfaces of N-doped carbon microtubes with enhanced biomimetic activity

Tubular structured composites have attracted great interest in catalysis research owing to their void-confinement effects. In this work, we synthesized a pair of hollow N-doped carbon microtubes (NCMTs) with Fe3O4 nanoparticles (NPs) encapsulated inside NCMTs (Fe3O4@NCMTs) and supported outside NCMTs (NCMTs@Fe3O4) while keeping other structural features the same. The impact of structural effects on the catalytic activities was investigated by comparing a pair of hollow-structured nanocomposites. It was found that the Fe3O4@NCMTs possessed a higher peroxidase-like activity when compared with NCMTs@Fe3O4, demonstrating structural superiority of Fe3O4@NCMTs. Based on the excellent peroxidase-like catalytic activity and stability of Fe3O4@NCMTs, an ultra-sensitive colorimetric method was developed for the detection of H2O2 and GSH with detection limits of 0.15 μM and 0.49 μM, respectively, which has potential application value in biological sciences and biotechnology.

Controlled assembly of cobalt embedded N-doped graphene nanosheets (Co@NGr) by pyrolysis of a mixed ligand Co(ii) MOF as a sacrificial template for high-performance electrocatalysts

The development of high-efficiency and durable bifunctional electrocatalysts is an important and challenging topic in the area of energy storage/conversion. Herein, we prepared metallic cobalt nanoparticle decorated N-doped graphitic sheets (Co@NGr) by adopting facile pyrolysis of a mixed ligand cobalt-based MOF (CoMOF-2) as a sacrificial template displaying good OER and HER activity. The catalytic material harvested at three different pyrolytic temperatures was characterized by various analytical methods such as PXRD, SEM, TEM, Raman, and XPS analyses. The catalytic activity of the obtained hybrid composite materials towards oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) was studied. Co@NGr-900 was found to be an efficient bifunctional electrocatalyst and 10 mA cm⁻² current density was afforded at an overpotential of 390 mV for OER and 340 mV for HER respectively. This study provides insight for the development of cost-effective nonprecious element-based electrocatalysts for water splitting which has relevance in energy storage and conversion. Catalytic performance is governed by the synergistic compositional effect of metallic cobalt/nitrogen-doping in the graphitic carbon increasing the electrical conductivity/active sites of the composite material.

Synthesis, characterization and application of monodispersed cobalt embedded nitrogen-doped graphene derived from a cobalt-based mixed ligand MOF by pyrolysis as a bifunctional electrocatalyst for water splitting have been investigated.

Light-induced synthesis of platinum/titania nanocapsules as an efficient, photosensitive and stable electrocatalyst

Novel Pt/TiO₂ nanocapsules (NCs) having sizes of 40–100 nm and walls of 6–17 nm were successfully synthesized.