Nanocomposite heterojunctions as sunlight-driven photocatalysts for hydrogen production from water splitting

Abstract

Hydrogen production via photocatalytic water splitting using sunlight has enormous potential in solving the worldwide energy and environmental crisis. The key challenge in this process is to develop efficient photocatalysts which must satisfy several criteria such as high chemical and photochemical stability, effective charge separation and strong sunlight absorption. The combination of different semiconductors to create composite materials offers a promising way to achieve efficient photocatalysts because doing so can improve the charge separation, light absorption and stability of the photocatalysts. In this review article, we summarized the most recent studies on semiconductor composites for hydrogen production under visible light irradiation. After a general introduction about the photocatalysis phenomenon, typical heterojunctions of widely studied heterogeneous semiconductors, including titanium dioxide, cadmium sulfide and graphitic carbon nitride are discussed in detail.

Hydrogen Generation through Solar Photocatalytic Processes: A Review of the Configuration and the Properties of Effective Metal-Based Semiconductor Nanomaterials

“…In this respect, some of the most relevant results collected in the literature review are reported in Table 2. At present, the most effective photocatalysts for photoreforming under visible light irradiation are CdS-based materials [125]. …”

Bi-Phasic photocatalytic particles prepared by sequential layer depositions for water cleaning and purification

“…[44,45] Most literature reports for the synthesis of heterojunctions describe products in the shape of core-shells, thin films, microscopic beads grafted with nano-particles, or related. [4, 12,46] Heterojunctions are beneficial for water cleaning as there is a need to maximise charge separation in order to ensure the longest carrier lifetime. This will then favour the delivery of both the electrons and the holes to the catalyst surface where they will perform the target redox degradation reactions.…”

“…[8, 12] Many synthesis pathways are feasible but the sol-gel combined with an annealing step has been utilised initially to show bi-phasic materials of TiO 2 . A simple dip-coating procedure has led to controlled thickness layers of different phases of titanium dioxide.…”

“…However a breakthrough in photocatalyst efficiency is needed for industrial up-scaling. Many versatile approaches have been investigated and have been the subject of recent extensive reviews: [4][5][6][7][8][9][10][11][12][13] metallic and non-metallic (co-)doping, [13][14][15][16][17][18][19][20] solidsolutions, [21,22] and the inclusion of surface plasmon resonance of precious metals, [23][24][25][26][27] dye-sensitizing with organic complexes, [28,29] Z-schemes, [30][31][32][33][34] metallic/semi-conductors (SC) or SC/SC heterojunctions (with or without an Ohmic layer), [35,36] UV-blue up-conversion sensitization [37] have all been considered.…”

Hybrid systems based on metal oxide and nanocarbons: electronic properties and applications for photocatalysis

“…[Miranda et al 2014] Moreover, a very common explanation is the possible charge transfer process, considering the hybrid as semiconductor/metal junctions between planar electrodes. Reza Gholipour et al 2015] In this 2.1 Nanocarbon-based hybrids context, it is of interest to distinguish between hybrid and composites and also, give evidences of hybridisation that can probe the charge transfer process. The main distinction between both is the interfacial contact formed between components.…”