Emerging Two-Dimensional Carbonaceous Materials for Electrocatalytic Energy Conversions: Rational Design of Active Structures through High-Temperature Chemistry

Abstract

Electrochemical energy conversion and storage technologies involving controlled catalysis provide a sustainable way to handle the intermittency of renewable energy sources, as well as to produce green chemicals/fuels in an ecofriendly manner. Core to such technology is the development of efficient electrocatalysts with high activity, selectivity, long-term stability, and low costs. Here, two-dimensional (2D) carbonaceous materials have emerged as promising contenders for advancing the chemistry in electrocatalysis. We review the emerging 2D carbonaceous materials for electrocatalysis, focusing primarily on the fine engineering of active structures through thermal condensation, where the design, fabrication, and mechanism investigations over different types of active moieties are summarized. Interestingly, all the recipes creating two-dimensionality on the carbon products also give specific electrocatalytic functionality, where the special mechanisms favoring 2D growth and their consequences on materials functionality are analyzed. Particularly, the structure–activity relationship between specific heteroatoms/defects and catalytic performance within 2D metal-free electrocatalysts is highlighted. Further, major challenges and opportunities for the practical implementation of 2D carbonaceous materials in electrocatalysis are summarized with the purpose to give future material design guidelines for attaining desirable catalytic structures.

Vacancy-Enhanced Sb–N4 Sites for the Oxygen Reduction Reaction and Zn–Air Battery

“…As shown in the electron paramagnetic resonance (EPR) pattern in Figure S16, a weak g = 1.983 signal corresponding to carbon vacancies can be observed in N–C. This indicates that a small number of carbon vacancies exist in N–C, which arise from the removal of N atoms from the N-doped carbon substrate during the high-temperature pyrolysis. , Moreover, a sharper peak can be detected in Sb SA –N–C than in N–C (Figure c), demonstrating more carbon vacancies in Sb SA –N–C . This is caused by the evaporation of species including Sb during high-temperature pyrolysis.…”