Abstract
Exploring a novel approach for the synthesis of oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) catalysts with inexpensive and high-activity is desirable. Herein, we report a bubble templating method to synthesize the graphene-like mesoporous carbon sheets with point defects as ORR/HER bifunctional electrocatalysts. The typical product shows excellent ORR performance including the positive onset potential (740 mV) and high diffusion-limiting current density (4.07 mA cm−2). Along with small Tafel slopes, the overpotential is determined to be about −453 and −378 mV at 10 mA cm−2 in both alkaline and acidic media, which suggests a good candidate for HER reaction as well. The superior catalytic activities are derived from the abundant point defects on the mesoporous carbon sheets surface, especially the existence of pyridinic and pyrrolic nitrogen species. This study may be an alternative route to prepare the novel functional materials for the applications of ORR and HER.
Highlights
Developing renewable and green clean energy technologies in response to the increasingly serious energy crisis and environmental problem has attracted great attention of the scientific community [1,2,3].The low catalysis efficiency of oxygen reduction and hydrogen evolution is the key bottleneck for the new energy conversion technologies in terms of proton exchange membrane fuel cell (PEMFC)and hydrogen production [4,5,6]
Graphene-like mesoporous carbon sheets as metal-free electrocatalysts have been broadly employed in the electrocatalytic oxygen reduction reaction (ORR)/hydrogen evolution reaction (HER) process [10]
We report the design and construction of graphene-like mesoporous carbon sheets through a new approach assisted by a CO2 -bubble templating approach
Summary
Developing renewable and green clean energy technologies in response to the increasingly serious energy crisis and environmental problem has attracted great attention of the scientific community [1,2,3].The low catalysis efficiency of oxygen reduction and hydrogen evolution is the key bottleneck for the new energy conversion technologies in terms of proton exchange membrane fuel cell (PEMFC)and hydrogen production [4,5,6]. The low catalysis efficiency of oxygen reduction and hydrogen evolution is the key bottleneck for the new energy conversion technologies in terms of proton exchange membrane fuel cell (PEMFC). To accelerate the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) kinetics, the introduction of platinum into catalyst is an effective means. Exploring a facile and low-cost synthetic process is of great significance to construct the highly-effective and resource-abundant electrocatalyst to replace the precious platinum-based materials. Catalytic reactions occur on the surface of catalysts, and catalytic activity is largely dependent upon the surface conditions, such as area and defects. Increasing the surface area can improve the physical collision rate and generating surface defects can enhance the chemical interaction between the reactants and the surface of catalysts. Graphene-like mesoporous carbon sheets as metal-free electrocatalysts have been broadly employed in the electrocatalytic ORR/HER process [10]
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