A Generic Conversion Strategy: From 2D Metal Carbides (M_xC_y) to M‐Self‐Doped Graphene toward High‐Efficiency Energy Applications

Abstract

This study first presents a subtle thermal‐chlorination strategy for a universal transformation of abundant 2D metal carbides (MxCy, e.g., Cr3C2, Mo2C, NbC, and VC) to 2D graphene and M‐self‐doped graphene (MG). The as‐obtained MG endows a transparent sheet architecture of one to four atomic layers. Simultaneously, MG with different M amounts is synthesized by tuning the chlorination parameters. Among them, the novel and representative Cr‐self‐doped graphene with optimal Cr amount (4.81 at%) demonstrates the outstanding electrochemical performance. It presents an energy density of 686 W h per kg electrode and a power density of more than 391 W per kg electrode as anode material of Li ion batteries, and four‐fold activity against the commercial iridium oxide electrode toward oxygen evolution reaction as well as a comparable oxygen reduction reaction performance to the commercial platinum catalyst. Moreover, this method is readily scalable to produce graphene and MG electrode materials on industrial levels.

Atomic and Electronic Reconstruction in Defective 0D Molybdenum Carbide Heterostructure for Regulating Lower‐Frequency Microwaves

“…[ 47,48 ] For the full scan spectrum (Figure S8, Supporting Information), obvious signals of Mo 3d, Mo 3p 1/2 , Mo 3p 3/2 , C 1s, and O 1s are presented in the Mo x C/C samples, while only C 1s is shown in the C sample. [ 49,50 ] High‐resolution Mo 3d spectrum (Figure 3e) can be mainly fitted into eight peaks, showing that Mo element has four states (2+, 3+, 4+, and 6+). For the three Mo x C/C samples, green peaks at about 229.3 and 232.4 eV match the Mo 4+ in MoO 2 , and the orange peaks at 233.0 and 236.1 eV refer to Mo 6+ in MoO 3 , which result from surface oxidation.…”

2D Dual‐Metal Zeolitic‐Imidazolate‐Framework‐(ZIF)‐Derived Bifunctional Air Electrodes with Ultrahigh Electrochemical Properties for Rechargeable Zinc–Air Batteries

“…It is interesting that nitrogen only coexist with cobalt across the tips of CNTs (Figure g; Figure S3, Supporting Information). Thus, abundant Co–N–C moieties as active sites are fully exposed on the surface of CNTs, which would be beneficial to the enhanced electrocatalytic properties.…”

Crystalline Co2V3O8@Amorphous Co−B Core‐Shell Nano‐Microsphere: Tunable Shell Layer Thickness, Faradaic Pseudocapacitive Mechanism, and Electrochemical Capacitor Applications

“…The distinctive peaks assigned to the B 1s, O 1s, Co 2p, and V 2p are evident from the full‐scale XPS spectra of Co 3 V 2 O 8 @Co−B‐2, indicating the existence of these elements in the Co 3 V 2 O 8 @Co−B‐2 nanocomposites. The strong diffraction peak emerging at 283.5 eV corresponds to C 1s [34–35] . Figure 2a‐II shows the magnified Co 2p peak of all samples.…”