Foreword
Oxygen Reduction Reaction (ORR) refers to the reduction reaction of oxygen. It
includes two-electron reaction and four-electron reaction. Two-electron reaction is
to reduce oxygen to H 2 0 2 , and four-electron reaction is to reduce oxygen to H 2 0.
Oxygen reduction is a very important reaction in the chemical field, such as energy
conversion and storage of new energy materials (including fuel cells, supercapacitors,
lithium secondary batteries, metal-air cells), and corrosion of industrial materials
such as steel.
Obviously, when we study oxygen reduction, we also involve the reaction mechanism of materials. Taking fuel cells and other electrochemical processes as examples,
oxygen reduction reaction is one of the key steps, and it mainly relies on precious
metal catalyst at present (such as Platinum). With the deepening of research, various
non-Pt (non-precious metal) catalysts have shown good electrocatalytic activity,
such as carbon materials doped with nitrogen. However, there is little research on
the working mechanism of this kind of carbon-based catalyst at present, and the
relationship between the arrangement of carbon atoms and nitrogen atoms and the
catalytic activity is still a mystery, which hinders people from further developing
higher performance catalysts that can replace precious metals. Recently, researchers
at the University of Tsukuba in Japan published an article in the American Journal of
Science (Active Sites of Nitrogen-Doped Carbon Materials for Oxygen Regeneration
Reaction Clarifying Using Model Catalysts. Science, 2016, 351: 361–365), which
clearly stated that the catalytic structure of nitrogen-doped carbon materials was
introduced, and the working mechanism of the reaction was put forward. In order to
solve this mystery, the team used graphite (highly oriented pyrolytic graphite) model
catalyst with definite hexagenics and controllable nitrogen atom doping to simulate
potential competition sites and analyze the reaction process. Among them, pyridine
nitrogen mainly appears at the edge of materials. By patterning the village bottom
to change the number of edges, the team was able to control the existence of pyridine nitrogen and test how it affects the catalytic performance. The results showed
that the catalytic sites were related to pyridine nitrogen. Carbon dioxide adsorption
experiments further showed that pyridine nitrogen created Lewis base sites. Further
analysis shows that the oxygen reduction sites of nitrogen-doped carbon materials are
v
Oxygen Reduction Reaction (ORR) refers to the reduction reaction of oxygen. It
includes two-electron reaction and four-electron reaction. Two-electron reaction is
to reduce oxygen to H 2 0 2 , and four-electron reaction is to reduce oxygen to H 2 0.
Oxygen reduction is a very important reaction in the chemical field, such as energy
conversion and storage of new energy materials (including fuel cells, supercapacitors,
lithium secondary batteries, metal-air cells), and corrosion of industrial materials
such as steel.
Obviously, when we study oxygen reduction, we also involve the reaction mechanism of materials. Taking fuel cells and other electrochemical processes as examples,
oxygen reduction reaction is one of the key steps, and it mainly relies on precious
metal catalyst at present (such as Platinum). With the deepening of research, various
non-Pt (non-precious metal) catalysts have shown good electrocatalytic activity,
such as carbon materials doped with nitrogen. However, there is little research on
the working mechanism of this kind of carbon-based catalyst at present, and the
relationship between the arrangement of carbon atoms and nitrogen atoms and the
catalytic activity is still a mystery, which hinders people from further developing
higher performance catalysts that can replace precious metals. Recently, researchers
at the University of Tsukuba in Japan published an article in the American Journal of
Science (Active Sites of Nitrogen-Doped Carbon Materials for Oxygen Regeneration
Reaction Clarifying Using Model Catalysts. Science, 2016, 351: 361–365), which
clearly stated that the catalytic structure of nitrogen-doped carbon materials was
introduced, and the working mechanism of the reaction was put forward. In order to
solve this mystery, the team used graphite (highly oriented pyrolytic graphite) model
catalyst with definite hexagenics and controllable nitrogen atom doping to simulate
potential competition sites and analyze the reaction process. Among them, pyridine
nitrogen mainly appears at the edge of materials. By patterning the village bottom
to change the number of edges, the team was able to control the existence of pyridine nitrogen and test how it affects the catalytic performance. The results showed
that the catalytic sites were related to pyridine nitrogen. Carbon dioxide adsorption
experiments further showed that pyridine nitrogen created Lewis base sites. Further
analysis shows that the oxygen reduction sites of nitrogen-doped carbon materials are
v