1. Introduction
In
recent decades, the excessive use of fossil fuels has led to a battery
of energy shortages and environmental pollution questions [1, 2].
Compared with traditional fossil
fuels, hydrogen is a clean and efficient energy carrier, since the
H2 evolution from water splitting is one of the more
promising methods with great promise to solve the problem [3, 4].
Noble metal
Pt
not only has excellent electron absorption ability, but also provides
abundant active sites, thus
Pt
has superior performance in terms of hydrogen production [5]. While
high cost and preciousness of Pt limit its large-scale application in
industry [6]. Hence, it is a challenging task to develop novel
photocatalyst with excellent activity and low-cost to replace noble
metals.
The various semiconductor photocatalysts have been extensively studied,
such as metallic sulfide (MoS2 [7], CdS [8], ZnS
[9], CdxZn1-xS [10, 11]),
metallic oxide (Co3O4 [12],
Cu2O [13]),
carbon-based materials (g-C3N4 [14])
and so on over the past decade.
Among
them, MnxCd1−xS solid was first reported
in 2010 [15], it has attracted widespread attention due to their
strong light absorption and adjustable energy band structures
[16, 17]. Peculiarly, it
overcomes the disadvantages of poor corrosion resistance and low
activity of CdS, and it has highly efficient H2production activity. However, pure
MnxCd1-xS still exhibits severe
recombination of photo-induced carriers that limited its activity in
photocatalytic reaction [18]. Thus, many effective strategies have
been presented to solve this problem, such as elemental doping [19],
constructing heterojunction [20],
morphological tailoring [21] and
so on. Thereinto, co-catalyst not only provide enough redox reaction
sites, but also reduce activation potentials and accelerate the transfer
of photo-generated electrons [22]. For example, Liu’s et al.
[23] utilised the CoP nanoparticles to modify
Mn0.2Cd0.8S nanowires and significantly
improved hydrogen production activity.
The mainly Ni-based co-catalysts were widely developed in the field of
photocatalytic hydrogen production [24, 25], including
Ni2P, NiSx and Ni(OH)2etc. As one of the Ni-based materials, NiSe2 collects
the advantages of high light absorption conversion ability, reduced band
gap and remarkable conductivity in terms of photoelectricity [26,
27]. Secondly, it has low cost and
yields more [28, 29]. Chen and co-workers
[30] used CdS and
NiSe2 to build a p-n heterojunction to improve hydrogen
production activity. However, NiSe2 has been widely
studied mostly in the field of eletrocatalysis, and there are few
reports on photocatalytic hydrogen
production. In addition to the
strategy of adding co-catalysts, by adjusting and controlling the
morphology, size and microstructure of nanomaterials, the composite
material giving rising to distinct optical and mechanical properties,
which is also a promising optimization method [31]. The hierarchical
three dimensional (3D) structures could availably inhibit the stacking
or aggregation of nanoparticles than two dimensional (2D) nanosheet
materials [32]. On the other hand, the surface of the 3D structure
can provide a large number of reaction sites and promote charge transfer
efficiency [31], which enhanced to the photocatalytic activity.
Inspired by aforementioned discussion,
in this work, we developed a facile
method to incorporate 0D Mn0.05Cd0.95S
into 3D NiSe2.
Through a series of detailed characterizations of the composition,
microstructure, BET surface areas and optical properties of
Mn0.05Cd0.95S/NiSe2composites, the effect of NiSe2 was researched on the
activity of material. In addition, we proposed a possible mechanism of
Mn0.05Cd0.95S/NiSe2composite based on the conclusions of photoelectrochemical measurements
and photoluminescence spectroscopy.