Sandwich-Like Co 3 O 4 /Graphene Nanocomposites as Anode Material for Lithium Ion Batteries

Deng

et al. 2021

ACS Appl. Nano Mater.

The reuse of waste biomass resources has recently become one of the most popular themes in the sustainable development of human society. To this end, waste scallion root was used as a biotemplate and carbon source to synthesize graphitic carbon-doped mesoporous Co3O4 nanocomposites (Co3O4/C) through a simple cobalt salt impregnation, carbonization, and low-temperature oxidation method. The effect of different carbon contents on the nanostructure and electrochemical performance is investigated. The hierarchical microtubes with a ribs-shaped inner wall in the product oxidized at 320 °C (Co3O4/C-2) are formed by the cross-linking of uniform small Co3O4 nanoparticles and 39.9% biomass-derived carbon. The Co3O4/C-2 nanocomposite has a large specific surface area of 360.2 m2·g–1, uniform mesopore size of 2.35 nm, and abundant oxygen vacancy defects. Such a unique nanostructure can exhibit a good pseudocapacitance behavior during the charge/discharge process, thereby effectively enhancing the lithium storage performance. The Co3O4/C-2 nanocomposite exhibits a high capacity and good rate capability. Even at 1.0 A g–1, it can still retain a capacity of 620 mA h g–1 after 1500 cycles. The superior capacity retention and long-cycling stability can be assigned to the synergistic effect of the unique nanostructure of the Co3O4/C-2 material (a uniform mesopore and large specific surface area), appropriate graphitic carbon doping, and pseudocapacitance contribution. Therefore, the reuse strategy of the waste scallion root biomass resource conforms to the concept of sustainable development and also provides a useful reference for the synthesis of other nanostructured anode materials with excellent performance.

Section: Introductionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Biomass-Derived Graphitic Carbon/Co₃O₄ Nanocomposites with Pseudocapacitance for Lithium Storage

Deng

et al. 2021

ACS Appl. Nano Mater.

“…00-074-1657). 55 The weak reflection at 62.54° is attributed to the (220) plane of cobalt( ii ) oxide; CoO (♦) (JCPDS card no. 43-1004).…”

Section: Resultsmentioning

confidence: 99%

Functionalised graphite felt anodes for enhanced power generation in membrane-less soil microbial fuel cells

et al. 2023

“…Also, no peaks associated with any impurities were observed. In Figure 3a, the as‐prepared catalyst was mostly present in Co 3 O 4 , where the peaks were assigned to a pure Co 3 O 4 phase [38–40] . The crystallite structure of the spent catalyst changed significantly with new diffraction peaks observed at 41, 47, and 76°2θ, corresponding to metallic Co (100), (101), (110), respectively, [41,42] while the peak at 44°2θ indicated the dominant Co 3 O 4 (404) phase.…”

Section: Resultsmentioning

confidence: 99%

“…In Figure 3a, the as-prepared catalyst was mostly present in Co 3 O 4 , where the peaks were assigned to a pure Co 3 O 4 phase. [38][39][40] The crystallite structure of the spent catalyst changed significantly with new diffraction peaks observed at 41, 47, and 76°2θ, corresponding to metallic Co (100), ( 101), (110), respectively, [41,42] while the peak at 44°2θ indicated the dominant Co 3 O 4 (404) phase. This confirms the change in the oxidation state of Co from higher one (Co 3 O 4 ) to lower one CoO x during the catalytic reaction under the reducing condition of RWGS and the applied polarization.…”

Section: Chemcatchem Correction)mentioning

confidence: 99%

Insight into Electrochemical Promotion of Cu/Co₃O₄ Catalysts for the Reverse Water Gas Shift Reaction

2023

In this study, Copper-modified Co 3 O 4 (Cu/Co 3 O 4 ) catalysts were investigated for the reverse water gas shift (RWGS) reaction at 200-400 °C under different CO 2 : H 2 ratios. It was found that the electrocatalytic performance of Co 3 O 4 was improved by loading 4 weight percent (wt.%) Cu nanoparticles (average size: 13 nm), which could be then used as an electrode in electrochemical promotion of catalysis (EPOC) studies. Under the applied voltages of + 2 V and À 1 V, the catalytic rates were suppressed and increased by about 40 % and 14 %, respectively. This was due to the changes in the active oxidation states of Cu and Co caused by O 2À migration under polarization, as confirmed by XPS, XRD, and cyclic voltammetry (CV). The study also revealed that the exchange current density (i 0 ) was counter-correlated with the open-circuit catalytic rate (r 0 ) and could serve as an informative tool for predicting the catalytic rate, which was demonstrated for the first time in the instance of RWGS reaction.