Molybdenum
disulfide (MoS2) attracts attention as a
highly efficient and low-cost photocatalyst for hydrogen production
but suffers from low conductance and high recombination rate of photogenerated
charge carriers. In this work, we investigate the MoS2 heterostructures
with graphene variants (GVs), including graphene, graphene oxide,
and their boron- and nitrogen-doped variants, by first-principles
calculations. A systematic comparison between graphene and graphene
oxide composites is performed, and the contrary effect of B and N
doping on interface function and hydrogen evolution is clarified.
We find that upon the formation of the interfaces, some amount of
electronic charge transfers from the GV side to the MoS2 layer, inducing the creation of an interface dipole and the reduction
of work function, which is more pronounced in the graphene oxide composites.
Moreover, our results reveal that N doping enhances the interface
functions by forming donor-type interface states, whereas B doping
reduces those functions by forming acceptor-type interface states.
However, the B-doped systems exhibit a lower Gibbs free energy difference
for hydrogen adsorption on the GV side than the N-doped systems, which
deserves much consideration in the design of new functional photocatalysts.