Search

In this study, a facile one-step method via pyrolysis was used to prepare nitrogen self-doped metal free catalysts derived from inexpensive biomass-chitin for an electrochemical CO2 reduction reaction (CO2RR). The microstructure, surface area, defect and N type in the catalysts were analyzed by BET, Raman, XPS, SEM and TEM. The sustainable chitin-based electrocatalyst prepared under optimized conditions has a surface area of 1972 m2/g and can convert CO2 into CO with FECO of ~90% at a potential of −0.59 V (vs. RHE). This good CO2RR performance results from plentiful active sites due to a high surface area, rich ultra-micropores that are beneficial to CO2 adsorption, abundant mesopores for CO2 transport improvement, a high content of pyridinic and graphitic nitrogen that is favorable for a CO2 reduction reaction and a low interfacial charge transfer resistance leading to a rapid electron transfer rate from the catalyst to CO2. This study shows the feasibility of N self-doped biomass-derived catalysts for CO2RR with the potential for large-scale industrial applications. [ABSTRACT FROM AUTHOR]

Environmentally friendly ammonia production is important for addressing the carbon emissions and substantial energy consumption that are currently associated with the chemical industry. In recent decades, many achievements are made in this area; however, low production yield, poor selectivity, and unsatisfactory Faradaic efficiency hinder large‐scale applications. 2D, metal‐free electrocatalysts stand out from other candidates because of their physical, electronic, and chemical properties. In this study, recent developments of 2D‐based electrochemical materials for converting dinitrogen into ammonia in ambient conditions are systematically reviewed. First, recent unique progress and challenges on novel 2D electrocatalysts for the nitrogen reduction reaction are summarized. Then, various synthetic strategies for electrochemical materials and the influence of these methods have on the intrinsic material performance are highlighted. Last, by comparing current engineering strategies, electrochemical tests, and computational calculations, the opportunities, critical issues, and scientific challenges for 2D nanomaterials as stable, efficient catalysts, are analyzed. On the basis of this comparison, technology solutions are provided and rational principles for future studies are proposed. [ABSTRACT FROM AUTHOR]

Electrochemical oxygen reduction for producing clean hydrogen peroxide (H2O2) is a promising alternative approach to the industrial anthraquinone method. At present, the most pressing challenge is the development of oxygen reduction electrocatalysts with sufficient activity, stability, and 2e− pathway selectivity. Here, the electrocatalytic properties of a series of graphitic carbon nitride (g‐C3N4) catalysts with different concentrations of nitrogen species (CNC and N(C)3) are explored for H2O2 production. Electrochemical studies show that the selectivity of g‐C3N4 for hydrogen peroxide generation in alkaline electrolytes reaches ≈90%. To explain the observed results, the structure, composition, and physical and chemical properties of g‐C3N4 catalysts synthesized from different precursors are compared with their electrocatalytic performance. This research contributes to the discovery and design of a high‐performance nitrogen‐doped carbon catalysts for the production of hydrogen peroxide. [ABSTRACT FROM AUTHOR]

Designing reactions in aqueous media has been one of the major challenges in modern organic synthesis, especially to avoid the use of large amounts of organic solvents whose disposal is a matter of grave concern from an environmental perspective. The oxidation of alcohols and amines is an essential and important step in the synthesis of many valuable products including polymers and pharmaceuticals. In recent times, there has been a surge in the use of water as a solvent in many organic reactions. This review focuses specifically on the oxidation reactions of alcohols and amines carried out in water media using transition metal catalysts, metal‐free catalysts and photocatalysts. [ABSTRACT FROM AUTHOR]