1 3
Topics in Current Chemistry (2019) 377:27
Following heterogeneous systems based on CdS, Xu et al. [91] reported multicore–shell CdS@ZIF-8 structures prepared by a two-step method. In the synthetic
protocol used in that study, polyvinylpyrrolidone (PVP) was used to stabilize the
nanoparticles of CdS and ZIF-8 shells with controlled thickness (from 13.6 to
102 nm) were formed on the surface of CdS. The photocatalytic performance evidenced the superiority of the core–shell structure compared to bare CdS nanoparticles. It was observed that core–shell structures showed better selectivity towards the
production of H 2 via the FA dehydrogenation reaction.
Zhang et al. [92] reported the preparation of composite aluminium-substituted
mesoporous silica (Al-HMS) molecular sieves coupled with CdS (CdS/Al-HMS).
The addition of Ru enhanced the photocatalytic activity as a consequence of the separation of photogenerated charge-carrier. Among the samples investigated, 0.07Ru/
CdS/Al-HMS exhibited the highest H 2 evolution activity (3.7 mL h
−1
).
Reisner et al. [93] investigated a CdS-based photocatalyst that efficiently converted FA into H 2 or CO by boosting the dehydrogenation or dehydration reaction,
respectively, by means of controlling selectivity of the reaction by using 3-mercaptopro-pionic acid (MPA) as a capping ligand (QD-MPA). Under visible-light irradiation, 52.1 mmol H 2 g
−1
cat h
−1
was generated with QD-MPA, which was enhanced
by the addition of Co (QD-MPA/CoCl 2 ; 116 mmol H 2 g
−1
cat h
−1
). However, 218 H 2
g
−1
cat h
−1
was achieved upon utilization of the full solar spectrum. Aside from the
effect of Co species in boosting catalytic performance, the latter study also proved
that selectivity of FA decomposition towards either H 2 or CO could be modified by
means of modifying the surface of CdS with ligands, such as [Me 3 O]BF 4 .
Piao et al. [94] reported on the use of ultrasmall cobalt phosphide nanoparticle (CoP) as efficient cocatalysts for photocatalytic dehydrogenation of FA, in
a study in which a CdS/CoP@RGO hybrid was evaluated. In order to obtain the
final catalysts, Co 3 O 4 @SiO 2 nanospheres were first prepared using a microemulsion method, and subsequently decorated by polyethyleneimine (PEI) and loaded
on graphene oxide (GO). After that, SiO 2 was removed to obtain Co 3 O 4 dispersed
on RGO, and the final CdS/CoP@RGO photocatalyst was prepared by phosphidation and loading CdS nanoparticles by ultrasonic treatment. The performance of
CoP was assessed by comparison with the counterpart noble-metal based catalysts
(CdS/Pt@RGO, CdS/Pd@RGO, CdS/Au@RGO, and CdS/Ru@RGO). The time of
flight (TOF) values were 196, 244, 106, 107, and 63 h
−1
, for CoP, Pt, Pd, Au, and
Ru, respectively, which evidenced the promising behavior of CoP as a cocatalyst for
the photocatalytic dehydrogenation of FA. Following with the non-noble-free photocatalysts, Khan et al. [95] reported a system based on Ni and Co loaded on CdS
nanorods (NRs), that were synthetized via controlled thermolysis of cadmium (II)
bis(dibutylcarbamodithioate) in ethylenediamine. Using this system, and due to the
redox potentials of Ni and Co in relation to the band positions of CdS NRs, electron
and holes were shuttled from CdS to Ni and CoCl 2 species, respectively, which led
to higher stability and photocatalytic performance. Evaluation of catalytic performance under visible-light irradiation revealed that H 2 production ability followed
the order CdS < Co/CdS < Ni/CdS < Co–Ni/CdS.
209
Reprinted from the journal
Topics in Current Chemistry (2019) 377:27
Following heterogeneous systems based on CdS, Xu et al. [91] reported multicore–shell CdS@ZIF-8 structures prepared by a two-step method. In the synthetic
protocol used in that study, polyvinylpyrrolidone (PVP) was used to stabilize the
nanoparticles of CdS and ZIF-8 shells with controlled thickness (from 13.6 to
102 nm) were formed on the surface of CdS. The photocatalytic performance evidenced the superiority of the core–shell structure compared to bare CdS nanoparticles. It was observed that core–shell structures showed better selectivity towards the
production of H 2 via the FA dehydrogenation reaction.
Zhang et al. [92] reported the preparation of composite aluminium-substituted
mesoporous silica (Al-HMS) molecular sieves coupled with CdS (CdS/Al-HMS).
The addition of Ru enhanced the photocatalytic activity as a consequence of the separation of photogenerated charge-carrier. Among the samples investigated, 0.07Ru/
CdS/Al-HMS exhibited the highest H 2 evolution activity (3.7 mL h
−1
).
Reisner et al. [93] investigated a CdS-based photocatalyst that efficiently converted FA into H 2 or CO by boosting the dehydrogenation or dehydration reaction,
respectively, by means of controlling selectivity of the reaction by using 3-mercaptopro-pionic acid (MPA) as a capping ligand (QD-MPA). Under visible-light irradiation, 52.1 mmol H 2 g
−1
cat h
−1
was generated with QD-MPA, which was enhanced
by the addition of Co (QD-MPA/CoCl 2 ; 116 mmol H 2 g
−1
cat h
−1
). However, 218 H 2
g
−1
cat h
−1
was achieved upon utilization of the full solar spectrum. Aside from the
effect of Co species in boosting catalytic performance, the latter study also proved
that selectivity of FA decomposition towards either H 2 or CO could be modified by
means of modifying the surface of CdS with ligands, such as [Me 3 O]BF 4 .
Piao et al. [94] reported on the use of ultrasmall cobalt phosphide nanoparticle (CoP) as efficient cocatalysts for photocatalytic dehydrogenation of FA, in
a study in which a CdS/CoP@RGO hybrid was evaluated. In order to obtain the
final catalysts, Co 3 O 4 @SiO 2 nanospheres were first prepared using a microemulsion method, and subsequently decorated by polyethyleneimine (PEI) and loaded
on graphene oxide (GO). After that, SiO 2 was removed to obtain Co 3 O 4 dispersed
on RGO, and the final CdS/CoP@RGO photocatalyst was prepared by phosphidation and loading CdS nanoparticles by ultrasonic treatment. The performance of
CoP was assessed by comparison with the counterpart noble-metal based catalysts
(CdS/Pt@RGO, CdS/Pd@RGO, CdS/Au@RGO, and CdS/Ru@RGO). The time of
flight (TOF) values were 196, 244, 106, 107, and 63 h
−1
, for CoP, Pt, Pd, Au, and
Ru, respectively, which evidenced the promising behavior of CoP as a cocatalyst for
the photocatalytic dehydrogenation of FA. Following with the non-noble-free photocatalysts, Khan et al. [95] reported a system based on Ni and Co loaded on CdS
nanorods (NRs), that were synthetized via controlled thermolysis of cadmium (II)
bis(dibutylcarbamodithioate) in ethylenediamine. Using this system, and due to the
redox potentials of Ni and Co in relation to the band positions of CdS NRs, electron
and holes were shuttled from CdS to Ni and CoCl 2 species, respectively, which led
to higher stability and photocatalytic performance. Evaluation of catalytic performance under visible-light irradiation revealed that H 2 production ability followed
the order CdS < Co/CdS < Ni/CdS < Co–Ni/CdS.
209
Reprinted from the journal