2 research outputs found
Enhanced Electrochemical and Photocatalytic Performance of Core–Shell CuS@Carbon Quantum Dots@Carbon Hollow Nanospheres
A controlled
structural morphology, high specific surface area, large void space,
and excellent biocompatibility are typical favorable properties in
electrochemical energy storage and photocatalytic studies; however,
a complete understanding about this essential topic still remains
a great challenge. Herein, we have developed a new type of functionalized
carbon hollow-structured nanospheres based on core–shell copper
sulfide@carbon quantum dots (CQDs)@carbon hollow nanosphere (CHNS)
architecture. This CuS@CQDs@C HNS is accomplished by a simple, scalable, <i>in situ</i> single-step hydrothermal method to produce the material
that can be employed as an electrode for electrochemical energy storage
and photocatalytic applications. Impressively, the CuS@CQDs@C HNS
nanostructure delivers exceptional electrochemical energy storage
characteristics with high specific capacitance (618 F g<sup>–1</sup> at a current density of 1 A g<sup>–1</sup>) and an excellent
rate capability with an extraordinary capacitance (462 F g<sup>–1</sup> at current density of 20 A g<sup>–1</sup>) and long cycle
life (95% capacitance retention after 4000 cycles). Further, the proposed
photocatalyst exhibited superior photocatalytic activity under solar
light due to the efficient electron transfer, which was revealed by
photoluminescence studies. Such superior electrochemical and photocatalytic
performance can be ascribed to the mutual contribution of CuS, CQDs,
and CHNS and unique core–shell architecture. These results
exhibit that the core–shell CuS@CQDs@C HNS nanostructure is
one of the potential candidates for supercapacitors and photocatalytic
applications
Highly Active and Durable Core–Shell fct-PdFe@Pd Nanoparticles Encapsulated NG as an Efficient Catalyst for Oxygen Reduction Reaction
Development of highly
active and durable catalysts for oxygen reduction
reaction (ORR) alternative to Pt-based catalyst is an essential topic
of interest in the research community but a challenging task. Here,
we have developed a new type of face-centered tetragonal (fct) PdFe-alloy
nanoparticle-encapsulated Pd (fct-PdFe@Pd) anchored onto nitrogen-doped
graphene (NG). This core–shell fct-PdFe@Pd@NG hybrid is fabricated
by a facile and cost-effective technique. The effect of temperature
on the transformation of face-centered cubic (fcc) to fct structure
and their effect on ORR activity are systematically investigated.
The core–shell fct-PdFe@Pd@NG hybrid exerts high synergistic
interaction between fct-PdFe@Pd NPs and NG shell, beneficial to enhance
the catalytic ORR activity and excellent durability. Impressively,
core–shell fct-PdFe@Pd@NG hybrid exhibits an excellent catalytic
activity for ORR with an onset potential of ∼0.97 V and a half-wave
potential of ∼0.83 V versus relative hydrogen electrode, ultrahigh
current density, and decent durability after 10 000 potential
cycles, which is significantly higher than that of marketable Pt/C
catalyst. Furthermore, the core–shell fct-PdFe@Pd@NG hybrid
also shows excellent tolerance to methanol, unlike the commercial
Pt/C catalyst. Thus, these findings open a new protocol for fabricating
another core–shell hybrid by facile and cost-effective techniques,
emphasizing great prospect in next-generation energy conversion and
storage applications