We have demonstrated the facile synthesis and photoelectrocatalytic activity of vertically aligned sandwich nanostructures consisting of carbon nanotube–PB nanocoating core–shell nanowires with CdS nanoparticles being sandwiched at their interface.
The as-prepared sandwich nanostructure of PB/CdS/CNT performed
much better in the photoelectrochemical reduction of
H2O2 than the commercial Pt/C in terms of current density, overpotential,
and cost-effectiveness. We attributed this superb performance
to the essential synergic effect rooting in the judicious
choice of materials and their assembly into well-defined sandwich
nanostructures (e.g., PB/CdS/CNT), wherein electron–hole pairs
separated in CdS upon photo radiation, the electrons flowed into
PB due to its relatively low Fermi level, and PB electrochemically
catalyzed the reduction of H2O2 via an ECE mechanism. The alignment
structure of PB/CdS/CNT additionally contributed to the
kinetics of the electrode reaction by expediting the mass diffusion
and electron shuttle, and affording a high surface area accessible to
chemical and electrochemical reactions. Our findings illuminated a
new avenue to devising cathodes for the fuel cells, the biofuel cell,
and the semi-fuel cells that use H2O2 as an alternative oxidizer to
oxygen for improved performance with friendly design at low cost.