Two-Dimensional Corrugated Porous Carbon‑, Nitrogen-Framework/Metal Heterojunction for Efficient Multielectron Transfer Processes with Controlled Kinetics

The
material choice for efficient electrocatalysts is limited because
it is necessary to be highly active as well as highly stable. One
direction to solve this issue is to understand elementary steps of
electrode processes and build an unconventional strategy for a conversion
of inert and, therefore, stable materials into efficient catalysts.
Herein, we propose a simple concept for obtaining catalysts from inert
and hence stable materials by forming their heterojunctions, namely,
covering inert Au with corrugated carbon–nitrogen-based two-dimensional
porous frameworks. It shows more than 10 times better activity for
the hydrogen evolution reaction than for the pure Au surface, and
it also demonstrates the high catalytic activity for the oxygen reduction
reaction (ORR) via an effective four-electron reduction
mechanism, which is different from the usual two-electron reduction
typical for ORR on Au surfaces. This activity induced by formation
of a heterojunction was analyzed by a conjugation of computational
and experimental methods and found to originate from alternative efficient
reaction pathways that emerged by the corrugated porous framework
and the Au surface. This work provides not only the method for creating
active surface but also the knowledge on elementary steps of such
complicated multielectron transfer reactions, thereby leading to intriguing
strategies for developing energy conversion reactions based on materials
which had never been considered as catalysts before.