CoMoO₃ Nanoplate/Reduced Graphene Oxide Composites Decorated with Ag Nanoparticles for Electrocatalytic Water Oxidation

Abstract

Electrochemical water decomposition is a clean energy-conversion method to convert electric energy into high-purity H2, wherein the sluggish kinetic process of oxygen evolution reaction (OER) extremely restricts the reaction kinetics of water decomposition. Focusing on this problem, we develop a flowery CoMoO3 nanoplate/reduced graphene oxide (rGO) nanoplate hybrid structure decorated with Ag nanoparticles (CoMoO3/rGO@Ag) to ameliorate the catalytic performance of OER. The reduced graphene oxide (rGO) wrapped outside can optimize electronic transmission and retain the structural integrity of internal flowery CoMoO3 nanoplates. Moreover, abundant ultrafine Ag nanoparticles are chosen as the auxiliary phase to cooperate with CoMoO3 and rGO phases, and such hybrid structure generates abundant heterostructure interfaces, which can offer more active sites and significantly enhance the reaction activity of the catalyst. After the incorporation of rGO and the adjustment of the Ag content, the optimized CoMoO3/rGO@Ag catalyst displays electrochemically synergistic enhancement toward OER, which shows a remarkably low overpotential (209 mV at 10 mA cm–2) and good cyclic endurance. These results effectively expound the rapid reaction kinetics and great stability of such heterostructure electrocatalyst toward water oxidation.

Enhanced Thermally Conductive and Microwave Absorbing Properties of Polymethyl Methacrylate/Ni@GNP Nanocomposites

“…The GNP with bare edges of Ni@GNP showed a lamellar structure under TEM, indicating that the graphitization degree of GNP was very low, and the thickness was sufficiently thin. 22 As shown in Figure 3b, the size of Ni nanoparticles on the GNP surface can be observed via TEM, with the nanoparticles' average diameter located in the range of 70−80 nm. The nano-Ni particles were helpful to form abundant hierarchical heterostructure interfaces between Ni and GNP, providing more opportunities for electromagnetic waves to interact with GNP.…”

“…It can be seen that Ni nanoparticles existed on the surface of GNP, indicative of the adhesion between them since Ni nanoparticles were still fixed on the surface of the GNP Ni@GNP nanohybrid in ethanol solution after strong ultrasound treatment before TEM observations. The GNP with bare edges of Ni@GNP showed a lamellar structure under TEM, indicating that the graphitization degree of GNP was very low, and the thickness was sufficiently thin . As shown in Figure b, the size of Ni nanoparticles on the GNP surface can be observed via TEM, with the nanoparticles’ average diameter located in the range of 70–80 nm.…”

DNA Origami-Templated Bimetallic Core–Shell Nanostructures for Enhanced Oxygen Evolution Reaction

“…However, large-scale hydrogen synthesis from electrochemical water splitting remains a concern due to the kinetically sluggish anodic oxygen evolution reaction (OER). − Cathodic hydrogen evolution reaction (HER) is a two-electron-transfer reaction while OER is a complicated four-electron–proton coupled reaction, and so higher overpotential is needed for OER than HER to overcome the kinetic energy barrier. Conventional electrocatalysts based on noble-metal oxides such as IrO 2 and RuO 2 are considered benchmark catalysts for OER exhibiting high activity in both acidic and alkaline electrolytes, but these materials are less abundant and suffer from poor sustainability. − Other transition metal-based nanostructures have also been reported for extensive use in electrocatalysis for OER due to their low cost and good stability. − …”

Optical Study of Few‐Layer Graphene Treated by Oxygen Plasma

“…[ 13 ] Fu Hua Gao et al synthesized fluorinated graphene oxide quantum dots (GOQDs) by the photochemical method and adjusted the band gap of GOQD by fluorination to make the PL blueshift. [ 14 ] For the study of luminescence of graphene‐like materials, a large amount of work has focused on GO and RGOQD, [ 15,16 ] while there is less research on chemical vapor deposition (CVD)‐graphene luminescence and a lack of systematization. Especially in recent years, with the rising production of CVD and the expanding research and applications of CVD graphene, it is of particular importance to study the optical properties of CVDFLG.…”