Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Heterostructures of MXenes and N-doped graphene as highly active
  bifunctional electrocatalysts   MXenes with versatile chemistry and superior electrical conductivity are
prevalent candidate materials for energy storage and catalysts. Inspired by
recent experiments of hybridizing MXenes with carbon materials, here we
theoretically design a series of heterostructures of N-doped graphene supported
by MXene monolayers as bifunctional electrocatalysts for the oxygen reduction
reaction (ORR) and hydrogen evolution reaction (HER). Our first-principles
calculations show that the graphitic sheet on V2C and Mo2C MXenes are highly
active with an ORR overpotential down to 0.36 V and reaction free energies for
the HER approaching zero, both with low kinetic barriers. Such outstanding
catalytic activities originate from the electronic coupling between the
graphitic sheet and the MXene, and can be correlated with the pz band center of
surface carbon atoms and the work function of the heterostructures. Our
findings screen a novel form of highly active electrocatalysts by taking
advantage of the fast charge transfer kinetics and strong interfacial coupling
of MXenes, and illuminate a universal mechanism for modulating the catalytic
properties of two-dimensional hybrid materials.

30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org