Ordered carbonaceous frameworks: a new class of carbon materials with molecular-level design

Ordered carbonaceous frameworks (OCFs) are a new class of carbon materials with a three-dimensional ordered structure synthesized by simple carbonization of metalloporphyrin crystals with polymerizable moieties. Carbonization via solid-state polymerization results in the formation of graphene-based ordered frameworks in which regularly aligned single-atomic metals are embedded. These unique structural features afford molecular-level designability like organic-based frameworks together with high electrical conductivity, thermal/chemical stability, and mechanical flexibility, towards a variety of applications including electrocatalysis and force-driven phase transition. This feature article summarizes the synthetic strategies and characteristics of OCFs in comparison with conventional organic-based frameworks and porous carbons, to discuss the potential applications and further development of the OCF family.

Hybrid phase 1T/2H-MoS2 with controllable 1T concentration and its promoted hydrogen evolution reaction

MoS2 has been investigated as a low-cost alternative to Pt in the electrochemical hydrogen evolution reaction. One of the promising methods to further activate MoS2 is phase engineering. MoS2 generally exhibits two kinds of crystalline phases: hexagonal 2H phase and octahedral 1T phase. 1T-MoS2 exhibits much better chemical/physical properties than natural semiconductor 2H-MoS2. However, 1T-MoS2 is metastable and its synthesis is still a challenge. Hybrid 1T/2H-MoS2 has been synthesized under relatively mild conditions, but controlling the 1T/2H ratio is still an issue which has not been discussed in detail. In this study, the synthesis methods of hybrid phase 1T/2H-MoS2 with controllable 1T concentration are investigated. The electrochemical hydrogen evolution reaction is then evaluated for 1T/2H-MoS2 with different 1T concentrations by performing both experiments and theoretical calculations.

Construction of Hybrid MoS2 Phase Coupled with SiC Heterojunctions with Promoted Photocatalytic Activity for 4-Nitrophenol Degradation

Phase engineering has been recognized as a promising method for boosting the catalytic activity of molybdenum sulfide (MoS₂) in the field of electrocatalysts and photocatalysts. The metallic 1T-MoS₂ exhibits much higher catalytic activity than natural semiconducting 2H-MoS₂ but suffers from harsh synthetic conditions and metastable physical/chemical properties. The hybrid 1T/2H phase MoS₂ shows higher catalytic activity than the 2H-MoS₂ and exhibits better stability than the 1T-MoS₂, which is more favorable than the 2H-MoS₂ in the photocatalytic reactions. In this study, we report a hydrothermal synthesis of the hybrid 1T/2H-MoS₂ phase coupled with SiC as a heterojunction photocatalyst for 4-nitrophenol (4-NP) degradation. SiC acts as a counterpart of the heterojunction structure and a morphology modifier, which dramatically promotes the reaction rate and visible light responsibility, providing new candidates and strategies in photocatalysis.